v9.1.2

changelog.md

@@ -1,5 +1,40 @@
 # Changelog
 
+## 2026-02-15 - 9.1.2 - fix(docs)
+document built-in concurrency control, rate limiting, and request deduplication in README
+
+- Added a new 'Concurrency Control & Rate Limiting' section to the README describing per-domain mutex, global concurrency cap, and sliding-window account rate limiting (defaults: 1 per domain, 5 global, 250 per 3 hours).
+- Documented new SmartAcme options in the interface: maxConcurrentIssuances, maxOrdersPerWindow, and orderWindowMs.
+- Added example code showing configuration of the limits and an example of request deduplication behavior (multiple subdomain requests resolving to a single ACME order).
+- Added an example subscription to certIssuanceEvents and updated the components table with TaskManager entry.
+- Change is documentation-only (README) — no code changes; safe patch release.
+
+## 2026-02-15 - 9.1.1 - fix(deps)
+bump @push.rocks/smarttime to ^4.2.3 and @push.rocks/taskbuffer to ^6.1.2
+
+- @push.rocks/smarttime: ^4.1.1 -> ^4.2.3
+- @push.rocks/taskbuffer: ^6.1.0 -> ^6.1.2
+- Only package.json dependency version updates; no code changes
+
+## 2026-02-15 - 9.1.0 - feat(smartacme)
+Integrate @push.rocks/taskbuffer TaskManager to coordinate ACME certificate issuance with per-domain mutex, global concurrency cap, and account-level rate limiting; refactor issuance flow into a single reusable cert-issuance task, expose issuance events, and update lifecycle to start/stop the TaskManager. Add configuration for concurrent issuances and sliding-window order limits, export taskbuffer types/plugins, and update tests and docs accordingly.
+
+- Added dependency @push.rocks/taskbuffer and re-exported ITaskEvent/ITaskMetadata in ts/index.ts; also imported/exported taskbuffer in ts/plugins.ts.
+- Replaced interestMap coordination with TaskManager + TaskConstraintGroup(s): 'cert-domain-mutex' (per-domain mutex, resultSharingMode: 'share-latest'), 'acme-global-concurrency' (global concurrency cap), and 'acme-account-rate-limit' (sliding-window rate limiter).
+- Introduced a single reusable Task named 'cert-issuance' and moved the ACME issuance flow into performCertificateIssuance(), splitting progress into named steps (prepare/authorize/finalize/store) and using notifyStep() for observable progress.
+- Exposed certIssuanceEvents via SmartAcme.certIssuanceEvents and wired TaskManager.start()/stop() into SmartAcme.start()/stop().
+- Added new ISmartAcmeOptions: maxConcurrentIssuances, maxOrdersPerWindow, orderWindowMs to control concurrency and rate limiting.
+- Updated tests to remove interestMap stubs and adapt to the taskbuffer-based flow; cleaned up client/retry stubbing in tests.
+- Updated readme.hints.md with guidance on concurrency, rate limiting, and taskbuffer integration.
+
+## 2026-02-15 - 9.0.1 - fix(acme-http-client)
+Destroy keep-alive HTTP agents and DNS client on shutdown to allow process exit; add destroy() on AcmeHttpClient and AcmeClient, wire agents into requests, and call client/smartdns destroy during SmartAcme.stop; documentation clarifications and expanded README (error handling, examples, default retry values).
+
+- ts/acme/acme.classes.http-client.ts: added per-protocol http/https agents (keepAlive: false), use agent for outgoing requests, and added destroy() to explicitly destroy agents and free sockets.
+- ts/acme/acme.classes.client.ts: added destroy() that forwards to the HTTP client to allow transport cleanup.
+- ts/smartacme.classes.smartacme.ts: SmartAcme.stop now calls client.destroy() and smartdns.destroy() (when present) to ensure child processes and sockets are terminated before exit; also ensures certmanager.close() is awaited.
+- readme.md: documentation improvements and clarifications (Let’s Encrypt spelling, added RFC 8555 compliance note, error handling / AcmeError usage examples, default retry parameter docs, UI/emoji improvements, and other wording/formatting updates).
+
 ## 2026-02-15 - 9.0.0 - BREAKING CHANGE(acme)
 Replace external acme-client with a built-in RFC8555-compliant ACME implementation and update public APIs accordingly
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@push.rocks/smartacme",
-  "version": "9.0.0",
+  "version": "9.1.2",
   "private": false,
   "description": "A TypeScript-based ACME client for LetsEncrypt certificate management with a focus on simplicity and power.",
   "main": "dist_ts/index.js",
@@ -48,8 +48,9 @@
     "@push.rocks/smartlog": "^3.1.10",
     "@push.rocks/smartnetwork": "^4.4.0",
     "@push.rocks/smartstring": "^4.1.0",
-    "@push.rocks/smarttime": "^4.1.1",
+    "@push.rocks/smarttime": "^4.2.3",
     "@push.rocks/smartunique": "^3.0.9",
+    "@push.rocks/taskbuffer": "^6.1.2",
     "@tsclass/tsclass": "^9.3.0"
   },
   "devDependencies": {

pnpm-lock.yaml

@@ -36,11 +36,14 @@ importers:
         specifier: ^4.1.0
         version: 4.1.0
       '@push.rocks/smarttime':
-        specifier: ^4.1.1
+        specifier: ^4.2.3
-        version: 4.1.1
+        version: 4.2.3
       '@push.rocks/smartunique':
         specifier: ^3.0.9
         version: 3.0.9
+      '@push.rocks/taskbuffer':
+        specifier: ^6.1.2
+        version: 6.1.2
       '@tsclass/tsclass':
         specifier: ^9.3.0
         version: 9.3.0
@@ -1012,8 +1015,8 @@ packages:
   '@push.rocks/smartstring@4.1.0':
     resolution: {integrity: sha512-Q4py/Nm3KTDhQ9EiC75yBtSTLR0KLMwhKM+8gGcutgKotZT6wJ3gncjmtD8LKFfNhb4lSaFMgPJgLrCHTOH6Iw==}
 
-  '@push.rocks/smarttime@4.1.1':
+  '@push.rocks/smarttime@4.2.3':
-    resolution: {integrity: sha512-Ha/3J/G+zfTl4ahpZgF6oUOZnUjpLhrBja0OQ2cloFxF9sKT8I1COaSqIfBGDtoK2Nly4UD4aTJ3JcJNOg/kgA==}
+    resolution: {integrity: sha512-8gMg8RUkrCG4p9NcEUZV7V6KpL24+jAMK02g7qyhfA6giz/JJWD0+8w8xjSR+G7qe16KVQ2y3RbvAL9TxmO36g==}
 
   '@push.rocks/smartunique@3.0.9':
     resolution: {integrity: sha512-q6DYQgT7/dqdWi9HusvtWCjdsFzLFXY9LTtaZV6IYNJt6teZOonoygxTdNt9XLn6niBSbLYrHSKvJNTRH/uK+g==}
@@ -1033,12 +1036,12 @@ packages:
   '@push.rocks/smartyaml@3.0.4':
     resolution: {integrity: sha512-1JRt+hnoc2zHw3AW+vXKlCdSVwqOmY/01fu+2HBviS0UDjoZCa+/rp6E3GaQb5lEEafKi8ENbffAfjXXp3N2xQ==}
 
-  '@push.rocks/taskbuffer@3.1.7':
-    resolution: {integrity: sha512-QktGVJPucqQmW/QNGnscf4FAigT1H7JWKFGFdRuDEaOHKFh9qN+PXG3QY7DtZ4jfXdGLxPN4yAufDuPSAJYFnw==}
-
   '@push.rocks/taskbuffer@3.5.0':
     resolution: {integrity: sha512-Y9WwIEIyp6oVFdj06j84tfrZIvjhbMb3DF52rYxlTeYLk3W7RPhSg1bGPCbtkXWeKdBrSe37V90BkOG7Qq8Pqg==}
 
+  '@push.rocks/taskbuffer@6.1.2':
+    resolution: {integrity: sha512-sdqKd8N/GidztQ1k3r8A86rLvD8Afyir5FjYCNJXDD9837JLoqzHaOKGltUSBsCGh2gjsZn6GydsY6HhXQgvZQ==}
+
   '@push.rocks/webrequest@3.0.37':
     resolution: {integrity: sha512-fLN7kP6GeHFxE4UH4r9C9pjcQb0QkJxHeAMwXvbOqB9hh0MFNKhtGU7GoaTn8SVRGRMPc9UqZVNwo6u5l8Wn0A==}
 
@@ -2290,6 +2293,10 @@ packages:
       typescript:
         optional: true
 
+  croner@10.0.1:
+    resolution: {integrity: sha512-ixNtAJndqh173VQ4KodSdJEI6nuioBWI0V1ITNKhZZsO0pEMoDxz539T4FTTbSZ/xIOSuDnzxLVRqBVSvPNE2g==}
+    engines: {node: '>=18.0'}
+
   croner@4.4.1:
     resolution: {integrity: sha512-aqVeeIPCf5/NZFlz4mN4MLEOs9xf4ODCmHQDs+577JFj8mK3RkKJz77h7+Rn94AijUqKdFNOUHM+v88d8p02UQ==}
 
@@ -2297,10 +2304,6 @@ packages:
     resolution: {integrity: sha512-9pSLe+tDJnmNak2JeMkz6ZmTCXP5p6vCxSd4kvDqrTJkqAP62j2uAEIZjf8cPDZIakStujqVzh5Y5MIWH3yYAw==}
     engines: {node: '>=6.0'}
 
-  croner@9.0.0:
-    resolution: {integrity: sha512-onMB0OkDjkXunhdW9htFjEhqrD54+M94i6ackoUkjHKbRnXdyEyKRelp4nJ1kAz32+s27jP1FsebpJCVl0BsvA==}
-    engines: {node: '>=18.0'}
-
   cross-spawn@7.0.6:
     resolution: {integrity: sha512-uV2QOWP2nWzsy2aMp8aRibhi9dlzF5Hgh5SHaB9OiTGEyDTiJJyx0uy51QXdyWbtAHNua4XJzUKca3OzKUd3vA==}
     engines: {node: '>= 8'}
@@ -2319,6 +2322,9 @@ packages:
   dayjs@1.11.13:
     resolution: {integrity: sha512-oaMBel6gjolK862uaPQOVTA7q3TZhuSvuMQAAglQDOWYO9A91IrAOUJEyKVlqJlHE0vq5p5UXxzdPfMH/x6xNg==}
 
+  dayjs@1.11.19:
+    resolution: {integrity: sha512-t5EcLVS6QPBNqM2z8fakk/NKel+Xzshgt8FFKAn+qwlD1pzZWxh0nVCrvFK7ZDb6XucZeF9z8C7CBWTRIVApAw==}
+
   debug@2.6.9:
     resolution: {integrity: sha512-bC7ElrdJaJnPbAP+1EotYvqZsb3ecl5wi6Bfi6BJTUcNowp6cvspg0jXznRTKDjm/E7AdgFBVeAPVMNcKGsHMA==}
     peerDependencies:
@@ -3584,8 +3590,8 @@ packages:
     resolution: {integrity: sha512-ASJqOugUF1bbzI35STMBUpZqdfYKlJugy6JBziGi2EE+AL5JPJGSzvpeVXojxrr0ViUYoToUjb5kjSEGf7Y83Q==}
     engines: {node: '>=14.16'}
 
-  pretty-ms@9.2.0:
+  pretty-ms@9.3.0:
-    resolution: {integrity: sha512-4yf0QO/sllf/1zbZWYnvWw3NxCQwLXKzIj0G849LSufP15BXKM0rbD2Z3wVnkMfjdn/CB0Dpp444gYAACdsplg==}
+    resolution: {integrity: sha512-gjVS5hOP+M3wMm5nmNOucbIrqudzs9v/57bWRHQWLYklXqoXKrVfYW2W9+glfGsqtPgpiz5WwyEEB+ksXIx3gQ==}
     engines: {node: '>=18'}
 
   progress@2.0.3:
@@ -4292,7 +4298,7 @@ snapshots:
       '@push.rocks/smartrx': 3.0.10
       '@push.rocks/smartsitemap': 2.0.4
       '@push.rocks/smartstream': 3.2.5
-      '@push.rocks/smarttime': 4.1.1
+      '@push.rocks/smarttime': 4.2.3
       '@push.rocks/taskbuffer': 3.5.0
       '@push.rocks/webrequest': 3.0.37
       '@push.rocks/webstore': 2.0.20
@@ -5533,8 +5539,11 @@ snapshots:
       '@push.rocks/smartpromise': 4.2.3
       typescript: 5.9.3
     transitivePeerDependencies:
+      - '@nuxt/kit'
       - aws-crt
+      - react
       - supports-color
+      - vue
 
   '@git.zone/tsbundle@2.8.3':
     dependencies:
@@ -5556,8 +5565,11 @@ snapshots:
       rolldown: 1.0.0-beta.52
       typescript: 5.9.3
     transitivePeerDependencies:
+      - '@nuxt/kit'
       - '@swc/helpers'
+      - react
       - supports-color
+      - vue
 
   '@git.zone/tspublish@1.11.0':
     dependencies:
@@ -5573,8 +5585,11 @@ snapshots:
       '@push.rocks/smartrequest': 5.0.1
       '@push.rocks/smartshell': 3.3.0
     transitivePeerDependencies:
+      - '@nuxt/kit'
       - aws-crt
+      - react
       - supports-color
+      - vue
 
   '@git.zone/tsrun@2.0.1':
     dependencies:
@@ -5605,7 +5620,7 @@ snapshots:
       '@push.rocks/smartrequest': 5.0.1
       '@push.rocks/smarts3': 3.0.3
       '@push.rocks/smartshell': 3.3.0
-      '@push.rocks/smarttime': 4.1.1
+      '@push.rocks/smarttime': 4.2.3
       '@types/ws': 8.18.1
       figures: 6.1.0
       ws: 8.19.0
@@ -5945,10 +5960,14 @@ snapshots:
       '@push.rocks/smartpromise': 4.2.3
       '@push.rocks/smartstring': 4.1.0
       '@push.rocks/smartunique': 3.0.9
-      '@push.rocks/taskbuffer': 3.1.7
+      '@push.rocks/taskbuffer': 3.5.0
       '@tsclass/tsclass': 4.4.4
     transitivePeerDependencies:
+      - '@nuxt/kit'
       - aws-crt
+      - react
+      - supports-color
+      - vue
 
   '@push.rocks/lik@6.2.2':
     dependencies:
@@ -5956,7 +5975,7 @@ snapshots:
       '@push.rocks/smartmatch': 2.0.0
       '@push.rocks/smartpromise': 4.2.3
       '@push.rocks/smartrx': 3.0.10
-      '@push.rocks/smarttime': 4.1.1
+      '@push.rocks/smarttime': 4.2.3
       '@types/minimatch': 5.1.2
       '@types/symbol-tree': 3.2.5
       symbol-tree: 3.2.4
@@ -5982,8 +6001,13 @@ snapshots:
       '@push.rocks/smartpath': 6.0.0
       '@push.rocks/smartpromise': 4.2.3
       '@push.rocks/smartrx': 3.0.10
-      '@push.rocks/taskbuffer': 3.1.7
+      '@push.rocks/taskbuffer': 3.5.0
       '@tsclass/tsclass': 9.3.0
+    transitivePeerDependencies:
+      - '@nuxt/kit'
+      - react
+      - supports-color
+      - vue
 
   '@push.rocks/qenv@6.1.3':
     dependencies:
@@ -6106,21 +6130,24 @@ snapshots:
       '@push.rocks/smartpromise': 4.2.3
       '@push.rocks/smartrx': 3.0.10
       '@push.rocks/smartstring': 4.1.0
-      '@push.rocks/smarttime': 4.1.1
+      '@push.rocks/smarttime': 4.2.3
       '@push.rocks/smartunique': 3.0.9
-      '@push.rocks/taskbuffer': 3.1.7
+      '@push.rocks/taskbuffer': 3.5.0
       '@tsclass/tsclass': 8.2.1
       mongodb: 6.16.0
     transitivePeerDependencies:
       - '@aws-sdk/credential-providers'
       - '@mongodb-js/zstd'
+      - '@nuxt/kit'
       - aws-crt
       - gcp-metadata
       - kerberos
       - mongodb-client-encryption
+      - react
       - snappy
       - socks
       - supports-color
+      - vue
 
   '@push.rocks/smartdata@7.0.15':
     dependencies:
@@ -6131,7 +6158,7 @@ snapshots:
       '@push.rocks/smartpromise': 4.2.3
       '@push.rocks/smartrx': 3.0.10
       '@push.rocks/smartstring': 4.1.0
-      '@push.rocks/smarttime': 4.1.1
+      '@push.rocks/smarttime': 4.2.3
       '@push.rocks/smartunique': 3.0.9
       '@push.rocks/taskbuffer': 3.5.0
       '@tsclass/tsclass': 9.3.0
@@ -6302,7 +6329,7 @@ snapshots:
       '@push.rocks/smartfile': 11.2.7
       '@push.rocks/smarthash': 3.2.6
       '@push.rocks/smartpromise': 4.2.3
-      '@push.rocks/smarttime': 4.1.1
+      '@push.rocks/smarttime': 4.2.3
       '@push.rocks/webrequest': 4.0.2
       '@tsclass/tsclass': 9.3.0
 
@@ -6347,13 +6374,16 @@ snapshots:
     transitivePeerDependencies:
       - '@aws-sdk/credential-providers'
       - '@mongodb-js/zstd'
+      - '@nuxt/kit'
       - aws-crt
       - gcp-metadata
       - kerberos
       - mongodb-client-encryption
+      - react
       - snappy
       - socks
       - supports-color
+      - vue
 
   '@push.rocks/smartnetwork@3.0.2':
     dependencies:
@@ -6385,12 +6415,15 @@ snapshots:
       '@push.rocks/smartpath': 6.0.0
       '@push.rocks/smartpromise': 4.2.3
       '@push.rocks/smartrequest': 4.4.2
-      '@push.rocks/smarttime': 4.1.1
+      '@push.rocks/smarttime': 4.2.3
       '@push.rocks/smartversion': 3.0.5
       package-json: 8.1.1
     transitivePeerDependencies:
+      - '@nuxt/kit'
       - aws-crt
+      - react
       - supports-color
+      - vue
 
   '@push.rocks/smartntml@2.0.8':
     dependencies:
@@ -6555,7 +6588,7 @@ snapshots:
       '@push.rocks/smartlog': 3.1.11
       '@push.rocks/smartpromise': 4.2.3
       '@push.rocks/smartrx': 3.0.10
-      '@push.rocks/smarttime': 4.1.1
+      '@push.rocks/smarttime': 4.2.3
       engine.io: 6.6.4
       socket.io: 4.8.1
       socket.io-client: 4.8.1
@@ -6605,16 +6638,16 @@ snapshots:
     dependencies:
       '@push.rocks/isounique': 1.0.5
 
-  '@push.rocks/smarttime@4.1.1':
+  '@push.rocks/smarttime@4.2.3':
     dependencies:
       '@push.rocks/lik': 6.2.2
       '@push.rocks/smartdelay': 3.0.5
       '@push.rocks/smartpromise': 4.2.3
-      croner: 9.0.0
+      croner: 10.0.1
       date-fns: 4.1.0
-      dayjs: 1.11.13
+      dayjs: 1.11.19
       is-nan: 1.3.2
-      pretty-ms: 9.2.0
+      pretty-ms: 9.3.0
 
   '@push.rocks/smartunique@3.0.9':
     dependencies:
@@ -6642,16 +6675,6 @@ snapshots:
     dependencies:
       yaml: 2.8.2
 
-  '@push.rocks/taskbuffer@3.1.7':
-    dependencies:
-      '@push.rocks/lik': 6.2.2
-      '@push.rocks/smartdelay': 3.0.5
-      '@push.rocks/smartlog': 3.1.11
-      '@push.rocks/smartpromise': 4.2.3
-      '@push.rocks/smartrx': 3.0.10
-      '@push.rocks/smarttime': 4.1.1
-      '@push.rocks/smartunique': 3.0.9
-
   '@push.rocks/taskbuffer@3.5.0':
     dependencies:
       '@design.estate/dees-element': 2.1.6
@@ -6660,7 +6683,23 @@ snapshots:
       '@push.rocks/smartlog': 3.1.11
       '@push.rocks/smartpromise': 4.2.3
       '@push.rocks/smartrx': 3.0.10
-      '@push.rocks/smarttime': 4.1.1
+      '@push.rocks/smarttime': 4.2.3
+      '@push.rocks/smartunique': 3.0.9
+    transitivePeerDependencies:
+      - '@nuxt/kit'
+      - react
+      - supports-color
+      - vue
+
+  '@push.rocks/taskbuffer@6.1.2':
+    dependencies:
+      '@design.estate/dees-element': 2.1.6
+      '@push.rocks/lik': 6.2.2
+      '@push.rocks/smartdelay': 3.0.5
+      '@push.rocks/smartlog': 3.1.11
+      '@push.rocks/smartpromise': 4.2.3
+      '@push.rocks/smartrx': 3.0.10
+      '@push.rocks/smarttime': 4.2.3
       '@push.rocks/smartunique': 3.0.9
     transitivePeerDependencies:
       - '@nuxt/kit'
@@ -8224,12 +8263,12 @@ snapshots:
     optionalDependencies:
       typescript: 5.9.3
 
+  croner@10.0.1: {}
+
   croner@4.4.1: {}
 
   croner@5.7.0: {}
 
-  croner@9.0.0: {}
-
   cross-spawn@7.0.6:
     dependencies:
       path-key: 3.1.1
@@ -8246,6 +8285,8 @@ snapshots:
 
   dayjs@1.11.13: {}
 
+  dayjs@1.11.19: {}
+
   debug@2.6.9:
     dependencies:
       ms: 2.0.0
@@ -9729,7 +9770,7 @@ snapshots:
     dependencies:
       parse-ms: 3.0.0
 
-  pretty-ms@9.2.0:
+  pretty-ms@9.3.0:
     dependencies:
       parse-ms: 4.0.0
 

readme.hints.md

@@ -28,6 +28,21 @@ Key files:
 
 Usage in `ts/plugins.ts`: `import * as acme from './acme/index.js'` (replaces `acme-client`)
 
+## Concurrency & Rate Limiting (taskbuffer integration)
+
+As of v9.1.0, `@push.rocks/lik.InterestMap` was replaced with `@push.rocks/taskbuffer.TaskManager` for coordinating concurrent certificate requests. This provides:
+
+- **Per-domain mutex** (`cert-domain-mutex`): Only one ACME issuance per TLD at a time, with `resultSharingMode: 'share-latest'` so queued callers get the same result without re-issuing.
+- **Global concurrency cap** (`acme-global-concurrency`): Limits total parallel ACME operations (default 5, configurable via `maxConcurrentIssuances`).
+- **Account-level rate limiting** (`acme-account-rate-limit`): Sliding-window rate limit (default 250 orders per 3 hours, configurable via `maxOrdersPerWindow`/`orderWindowMs`) to stay under Let's Encrypt limits.
+- **Step-based progress**: The cert issuance task uses `notifyStep()` for prepare/authorize/finalize/store phases, observable via `smartAcme.certIssuanceEvents`.
+
+Key implementation details:
+- A single reusable `Task` named `cert-issuance` handles all domains via `triggerTaskConstrained()` with different inputs.
+- The `shouldExecute` callback on the domain mutex checks the certmanager cache as a safety net.
+- `TaskManager.start()` is called in `SmartAcme.start()` and `TaskManager.stop()` in `SmartAcme.stop()`.
+- The "no cronjobs specified" log messages during tests come from taskbuffer's internal CronManager polling — harmless noise when no cron tasks are scheduled.
+
 ## Dependency Notes
 
 - `acme-client` was replaced with custom implementation in `ts/acme/` + `@peculiar/x509` for CSR generation

readme.md

@@ -1,6 +1,6 @@
 # @push.rocks/smartacme
 
-A TypeScript-based ACME client for LetsEncrypt certificate management with a focus on simplicity and power. 🔒
+A TypeScript-based ACME client for Let's Encrypt certificate management with a focus on simplicity and power. 🔒
 
 ## Issue Reporting and Security
 
@@ -16,9 +16,9 @@ Ensure your project uses TypeScript and ECMAScript Modules (ESM).
 
 ## Usage
 
-`@push.rocks/smartacme` automates the full ACME certificate lifecycle — obtaining, renewing, and storing SSL/TLS certificates from Let's Encrypt. It supports pluggable challenge handlers (DNS-01, HTTP-01) and pluggable certificate storage backends (MongoDB, in-memory, or your own).
+`@push.rocks/smartacme` automates the full ACME certificate lifecycle — obtaining, renewing, and storing SSL/TLS certificates from Let's Encrypt. It features a built-in RFC 8555-compliant ACME protocol implementation, pluggable challenge handlers (DNS-01, HTTP-01), pluggable certificate storage backends (MongoDB, in-memory, or your own), structured error handling with smart retry logic, and built-in concurrency control with rate limiting to keep you safely within Let's Encrypt limits.
 
-### Quick Start
+### 🚀 Quick Start
 
 ```typescript
 import { SmartAcme, certmanagers, handlers } from '@push.rocks/smartacme';
@@ -47,39 +47,44 @@ await smartAcme.start();
 
 // 4. Get a certificate
 const cert = await smartAcme.getCertificateForDomain('example.com');
-console.log(cert.publicKey);  // PEM certificate
+console.log(cert.publicKey);  // PEM certificate chain
 console.log(cert.privateKey); // PEM private key
 
 // 5. Clean up
 await smartAcme.stop();
 ```
 
-### SmartAcme Options
+### ⚙️ SmartAcme Options
 
 ```typescript
 interface ISmartAcmeOptions {
   accountEmail: string;                      // ACME account email
   accountPrivateKey?: string;                // Optional account key (auto-generated if omitted)
   certManager: ICertManager;                 // Certificate storage backend
-  environment: 'production' | 'integration'; // LetsEncrypt environment
+  environment: 'production' | 'integration'; // Let's Encrypt environment
   challengeHandlers: IChallengeHandler[];    // At least one handler required
   challengePriority?: string[];              // e.g. ['dns-01', 'http-01']
   retryOptions?: {                           // Optional retry/backoff config
-    retries?: number;
+    retries?: number;                        // Default: 10
-    factor?: number;
+    factor?: number;                         // Default: 4
-    minTimeoutMs?: number;
+    minTimeoutMs?: number;                   // Default: 1000
-    maxTimeoutMs?: number;
+    maxTimeoutMs?: number;                   // Default: 60000
   };
+  // Concurrency & rate limiting
+  maxConcurrentIssuances?: number;           // Global cap on parallel ACME ops (default: 5)
+  maxOrdersPerWindow?: number;               // Max orders in sliding window (default: 250)
+  orderWindowMs?: number;                    // Sliding window duration in ms (default: 3 hours)
 }
 ```
 
-### Getting Certificates
+### 📜 Getting Certificates
 
 ```typescript
 // Standard certificate for a single domain
 const cert = await smartAcme.getCertificateForDomain('example.com');
 
-// Include wildcard certificate (requires DNS-01 handler)
+// Include wildcard coverage (requires DNS-01 handler)
+// Issues a single cert covering example.com AND *.example.com
 const certWithWildcard = await smartAcme.getCertificateForDomain('example.com', {
   includeWildcard: true,
 });
@@ -90,25 +95,98 @@ const wildcardCert = await smartAcme.getCertificateForDomain('*.example.com');
 
 Certificates are automatically cached and reused when still valid. Renewal happens automatically when a certificate is within 10 days of expiration.
 
-### Certificate Object
+### 📦 Certificate Object
 
-The returned `SmartacmeCert` object has these properties:
+The returned `SmartacmeCert` (also exported as `Cert`) object has these properties:
 
 | Property     | Type     | Description                          |
 |-------------|----------|--------------------------------------|
 | `id`        | `string` | Unique certificate identifier        |
 | `domainName`| `string` | Domain the cert is issued for        |
-| `publicKey` | `string` | PEM-encoded certificate              |
+| `publicKey` | `string` | PEM-encoded certificate chain        |
 | `privateKey`| `string` | PEM-encoded private key              |
 | `csr`       | `string` | Certificate Signing Request          |
 | `created`   | `number` | Timestamp of creation                |
 | `validUntil`| `number` | Timestamp of expiration              |
 
+Useful methods:
+
+```typescript
+cert.isStillValid();    // true if not expired
+cert.shouldBeRenewed(); // true if expires within 10 days
+```
+
+## 🔀 Concurrency Control & Rate Limiting
+
+When many callers request certificates concurrently (e.g., hundreds of subdomains under the same TLD), SmartAcme automatically handles deduplication, concurrency, and rate limiting using a built-in task manager powered by `@push.rocks/taskbuffer`.
+
+### How It Works
+
+Three constraint layers protect your ACME account:
+
+| Layer | What It Does | Default |
+|-------|-------------|---------|
+| **Per-domain mutex** | Only one issuance runs per base domain at a time. Concurrent requests for the same domain automatically wait and receive the same certificate result. | 1 concurrent per domain |
+| **Global concurrency cap** | Limits total parallel ACME operations across all domains. | 5 concurrent |
+| **Account rate limit** | Sliding-window rate limiter that keeps you under Let's Encrypt's 300 orders/3h account limit. | 250 per 3 hours |
+
+### 🛡️ Automatic Request Deduplication
+
+If 100 requests come in for subdomains of `example.com` simultaneously, only **one** ACME issuance runs. All other callers automatically wait and receive the same certificate — no duplicate orders, no wasted rate limit budget.
+
+```typescript
+// These all resolve to the same certificate with a single ACME order:
+const results = await Promise.all([
+  smartAcme.getCertificateForDomain('app.example.com'),
+  smartAcme.getCertificateForDomain('api.example.com'),
+  smartAcme.getCertificateForDomain('cdn.example.com'),
+]);
+```
+
+### ⚡ Configuring Limits
+
+```typescript
+const smartAcme = new SmartAcme({
+  accountEmail: 'admin@example.com',
+  certManager,
+  environment: 'production',
+  challengeHandlers: [dnsHandler],
+  maxConcurrentIssuances: 10,     // Allow up to 10 parallel ACME issuances
+  maxOrdersPerWindow: 200,        // Cap at 200 orders per window
+  orderWindowMs: 2 * 60 * 60_000, // 2-hour sliding window
+});
+```
+
+### 📊 Observing Issuance Progress
+
+Subscribe to the `certIssuanceEvents` stream to observe certificate issuance progress in real-time:
+
+```typescript
+smartAcme.certIssuanceEvents.subscribe((event) => {
+  switch (event.type) {
+    case 'started':
+      console.log(`🔄 Issuance started: ${event.task.name}`);
+      break;
+    case 'step':
+      console.log(`📍 Step: ${event.stepName} (${event.task.currentProgress}%)`);
+      break;
+    case 'completed':
+      console.log(`✅ Issuance completed: ${event.task.name}`);
+      break;
+    case 'failed':
+      console.log(`❌ Issuance failed: ${event.error}`);
+      break;
+  }
+});
+```
+
+Each issuance goes through four steps: **prepare** (10%) → **authorize** (40%) → **finalize** (30%) → **store** (20%).
+
 ## Certificate Managers
 
 SmartAcme uses the `ICertManager` interface for pluggable certificate storage.
 
-### MongoCertManager
+### 🗄️ MongoCertManager
 
 Persistent storage backed by MongoDB using `@push.rocks/smartdata`:
 
@@ -122,7 +200,7 @@ const certManager = new certmanagers.MongoCertManager({
 });
 ```
 
-### MemoryCertManager
+### 🧪 MemoryCertManager
 
 In-memory storage, ideal for testing or ephemeral workloads:
 
@@ -132,13 +210,12 @@ import { certmanagers } from '@push.rocks/smartacme';
 const certManager = new certmanagers.MemoryCertManager();
 ```
 
-### Custom Certificate Manager
+### 🔧 Custom Certificate Manager
 
 Implement the `ICertManager` interface for your own storage backend:
 
 ```typescript
-import type { ICertManager } from '@push.rocks/smartacme';
+import type { ICertManager, Cert } from '@push.rocks/smartacme';
-import { Cert } from '@push.rocks/smartacme';
 
 class RedisCertManager implements ICertManager {
   async init(): Promise<void> { /* connect */ }
@@ -166,7 +243,7 @@ const cfAccount = new cloudflare.CloudflareAccount('YOUR_CF_TOKEN');
 const dnsHandler = new handlers.Dns01Handler(cfAccount);
 ```
 
-DNS-01 is required for wildcard certificates and works regardless of server accessibility.
+DNS-01 is **required** for wildcard certificates and works regardless of server accessibility.
 
 ### 📁 Http01Webroot
 
@@ -197,12 +274,12 @@ app.use((req, res, next) => memHandler.handleRequest(req, res, next));
 
 Perfect for serverless or container environments where filesystem access is limited.
 
-### Custom Challenge Handler
+### 🔧 Custom Challenge Handler
 
 Implement `IChallengeHandler<T>` for custom challenge types:
 
 ```typescript
-import type { IChallengeHandler } from '@push.rocks/smartacme';
+import type { handlers } from '@push.rocks/smartacme';
 
 interface MyChallenge {
   type: string;
@@ -210,28 +287,54 @@ interface MyChallenge {
   keyAuthorization: string;
 }
 
-class MyHandler implements IChallengeHandler<MyChallenge> {
+class MyHandler implements handlers.IChallengeHandler<MyChallenge> {
   getSupportedTypes(): string[] { return ['http-01']; }
-  async prepare(ch: MyChallenge): Promise<void> { /* ... */ }
+  async prepare(ch: MyChallenge): Promise<void> { /* set up challenge response */ }
-  async cleanup(ch: MyChallenge): Promise<void> { /* ... */ }
+  async cleanup(ch: MyChallenge): Promise<void> { /* tear down */ }
   async checkWetherDomainIsSupported(domain: string): Promise<boolean> { return true; }
 }
 ```
 
+## Error Handling
+
+SmartAcme provides structured ACME error handling via the `AcmeError` class, which carries full RFC 8555 error information:
+
+```typescript
+import { AcmeError } from '@push.rocks/smartacme/ts/acme/acme.classes.error.js';
+
+try {
+  const cert = await smartAcme.getCertificateForDomain('example.com');
+} catch (err) {
+  if (err instanceof AcmeError) {
+    console.log(err.status);        // HTTP status code (e.g. 429)
+    console.log(err.type);          // ACME error URN (e.g. 'urn:ietf:params:acme:error:rateLimited')
+    console.log(err.detail);        // Human-readable message
+    console.log(err.subproblems);   // Per-identifier sub-errors (RFC 8555 §6.7.1)
+    console.log(err.retryAfter);    // Retry-After value in seconds
+    console.log(err.isRateLimited); // true for 429 or rateLimited type
+    console.log(err.isRetryable);   // true for 429, 503, 5xx, badNonce; false for 403/404/409
+  }
+}
+```
+
+The built-in retry logic is **error-aware**: non-retryable errors (403, 404, 409) are thrown immediately without wasting retry attempts, and rate-limited responses respect the server's `Retry-After` header instead of using blind exponential backoff.
+
 ## Domain Matching
 
 SmartAcme automatically maps subdomains to their base domain for certificate lookups:
 
-```typescript
+```
-// subdomain.example.com → certificate for example.com
+subdomain.example.com → certificate for example.com  ✅
-// *.example.com → certificate for example.com
+*.example.com         → certificate for example.com  ✅
-// a.b.example.com → not supported (4+ level domains)
+a.b.example.com       → not supported (4+ levels)    ❌
 ```
 
 ## Environment
 
-- **`production`** — Uses LetsEncrypt production servers. Rate limits apply.
+| Environment     | Description |
-- **`integration`** — Uses LetsEncrypt staging servers. No rate limits, but certificates are not trusted by browsers. Use for testing.
+|----------------|-------------|
+| `production`   | Let's Encrypt production servers. Certificates are browser-trusted. [Rate limits](https://letsencrypt.org/docs/rate-limits/) apply. |
+| `integration`  | Let's Encrypt staging servers. No rate limits, but certificates are **not** browser-trusted. Use for testing. |
 
 ## Complete Example with HTTP-01
 
@@ -269,13 +372,21 @@ await smartAcme.stop();
 server.close();
 ```
 
-## Testing
+## Architecture
 
-```bash
+Under the hood, SmartAcme uses a fully custom RFC 8555-compliant ACME protocol implementation (no external ACME libraries). Key internal modules:
-pnpm test
-```
 
-Tests use `@git.zone/tstest` with the tapbundle assertion library.
+| Module | Purpose |
+|--------|---------|
+| `AcmeClient` | Top-level ACME facade — orders, authorizations, finalization |
+| `AcmeCrypto` | RSA key generation, JWK/JWS (RFC 7515/7638), CSR via `@peculiar/x509` |
+| `AcmeHttpClient` | JWS-signed HTTP transport with nonce management and structured logging |
+| `AcmeError` | Structured error class with type URN, subproblems, Retry-After, retryability |
+| `AcmeOrderManager` | Order lifecycle — create, poll, finalize, download certificate |
+| `AcmeChallengeManager` | Key authorization computation and challenge completion |
+| `TaskManager` | Constraint-based concurrency control, rate limiting, and request deduplication via `@push.rocks/taskbuffer` |
+
+All cryptographic operations use `node:crypto`. The only external crypto dependency is `@peculiar/x509` for CSR generation.
 
 ## License and Legal Information
 

test/test.http01-only.ts

@@ -25,16 +25,12 @@ tap.test('HTTP-01 only configuration should work for regular domains', async ()
     smartAcmeInstance.certmatcher = {
       getCertificateDomainNameByDomainName: (domain: string) => domain.replace('*.', '')
     } as any;
-    smartAcmeInstance.interestMap = {
-      checkInterest: async () => false,
-      addInterest: async () => ({ interestFullfilled: new Promise(() => {}), fullfillInterest: () => {}, destroy: () => {} } as any)
-    } as any;
     await smartAcmeInstance.certmanager.init();
   };
   await smartAcmeInstance.start();
 
   // Stub the core certificate methods to avoid actual ACME calls
-  smartAcmeInstance.client = {
+  (smartAcmeInstance as any).client = {
     createOrder: async (orderPayload: any) => {
       // Verify no wildcard is included in default request
       const identifiers = orderPayload.identifiers;
@@ -48,7 +44,7 @@ tap.test('HTTP-01 only configuration should work for regular domains', async ()
     getCertificate: async () => '-----BEGIN CERTIFICATE-----\ntest\n-----END CERTIFICATE-----',
   } as any;
 
-  smartAcmeInstance.retry = async (fn: () => Promise<any>) => fn();
+  (smartAcmeInstance as any).retry = async (fn: () => Promise<any>) => fn();
   
   // Mock certmanager methods
   smartAcmeInstance.certmanager.retrieveCertificate = async () => null;
@@ -83,16 +79,12 @@ tap.test('should only include wildcard when explicitly requested with DNS-01', a
     smartAcmeInstance.certmatcher = {
       getCertificateDomainNameByDomainName: (domain: string) => domain.replace('*.', '')
     } as any;
-    smartAcmeInstance.interestMap = {
-      checkInterest: async () => false,
-      addInterest: async () => ({ interestFullfilled: new Promise(() => {}), fullfillInterest: () => {}, destroy: () => {} } as any)
-    } as any;
     await smartAcmeInstance.certmanager.init();
   };
   await smartAcmeInstance.start();
 
   // Stub the core certificate methods
-  smartAcmeInstance.client = {
+  (smartAcmeInstance as any).client = {
     createOrder: async (orderPayload: any) => {
       const identifiers = orderPayload.identifiers;
       expect(identifiers.length).toEqual(2);
@@ -105,7 +97,7 @@ tap.test('should only include wildcard when explicitly requested with DNS-01', a
     getCertificate: async () => '-----BEGIN CERTIFICATE-----\ntest\n-----END CERTIFICATE-----',
   } as any;
 
-  smartAcmeInstance.retry = async (fn: () => Promise<any>) => fn();
+  (smartAcmeInstance as any).retry = async (fn: () => Promise<any>) => fn();
   
   // Mock certmanager methods
   smartAcmeInstance.certmanager.retrieveCertificate = async () => null;
@@ -136,10 +128,6 @@ tap.test('should skip wildcard if requested but no DNS-01 handler available', as
     smartAcmeInstance.certmatcher = {
       getCertificateDomainNameByDomainName: (domain: string) => domain.replace('*.', '')
     } as any;
-    smartAcmeInstance.interestMap = {
-      checkInterest: async () => false,
-      addInterest: async () => ({ interestFullfilled: new Promise(() => {}), fullfillInterest: () => {}, destroy: () => {} } as any)
-    } as any;
     await smartAcmeInstance.certmanager.init();
   };
   await smartAcmeInstance.start();
@@ -154,7 +142,7 @@ tap.test('should skip wildcard if requested but no DNS-01 handler available', as
   };
 
   // Stub the core certificate methods
-  smartAcmeInstance.client = {
+  (smartAcmeInstance as any).client = {
     createOrder: async (orderPayload: any) => {
       const identifiers = orderPayload.identifiers;
       // Should only have regular domain, no wildcard
@@ -167,7 +155,7 @@ tap.test('should skip wildcard if requested but no DNS-01 handler available', as
     getCertificate: async () => '-----BEGIN CERTIFICATE-----\ntest\n-----END CERTIFICATE-----',
   } as any;
 
-  smartAcmeInstance.retry = async (fn: () => Promise<any>) => fn();
+  (smartAcmeInstance as any).retry = async (fn: () => Promise<any>) => fn();
   
   // Mock certmanager methods
   smartAcmeInstance.certmanager.retrieveCertificate = async () => null;

ts/00_commitinfo_data.ts

@@ -3,6 +3,6 @@
  */
 export const commitinfo = {
   name: '@push.rocks/smartacme',
-  version: '9.0.0',
+  version: '9.1.2',
   description: 'A TypeScript-based ACME client for LetsEncrypt certificate management with a focus on simplicity and power.'
 }

ts/acme/acme.classes.client.ts

@@ -96,4 +96,11 @@ export class AcmeClient {
   async getCertificate(order: IAcmeOrder): Promise<string> {
     return this.orderManager.getCertificate(order);
   }
+
+  /**
+   * Destroy HTTP transport to release sockets and allow process exit.
+   */
+  destroy(): void {
+    this.httpClient.destroy();
+  }
 }

ts/acme/acme.classes.http-client.ts

@@ -17,11 +17,23 @@ export class AcmeHttpClient {
   private nonce: string | null = null;
   public kid: string | null = null;
   private logger?: TAcmeLogger;
+  private httpsAgent: https.Agent;
+  private httpAgent: http.Agent;
 
   constructor(directoryUrl: string, accountKeyPem: string, logger?: TAcmeLogger) {
     this.directoryUrl = directoryUrl;
     this.accountKeyPem = accountKeyPem;
     this.logger = logger;
+    this.httpsAgent = new https.Agent({ keepAlive: false });
+    this.httpAgent = new http.Agent({ keepAlive: false });
+  }
+
+  /**
+   * Destroy HTTP agents to release sockets and allow process exit.
+   */
+  destroy(): void {
+    this.httpsAgent.destroy();
+    this.httpAgent.destroy();
   }
 
   private log(level: string, message: string, data?: any): void {
@@ -186,6 +198,7 @@ export class AcmeHttpClient {
         path: urlObj.pathname + urlObj.search,
         method,
         headers: requestHeaders,
+        agent: isHttps ? this.httpsAgent : this.httpAgent,
       };
 
       const req = lib.request(options, (res) => {

ts/index.ts

@@ -9,3 +9,6 @@ export { certmanagers };
 // handlers
 import * as handlers from './handlers/index.js';
 export { handlers };
+
+// re-export taskbuffer event types for consumers
+export type { ITaskEvent, ITaskMetadata } from '@push.rocks/taskbuffer';

ts/plugins.ts

@@ -19,6 +19,7 @@ import * as smartnetwork from '@push.rocks/smartnetwork';
 import * as smartunique from '@push.rocks/smartunique';
 import * as smartstring from '@push.rocks/smartstring';
 import * as smarttime from '@push.rocks/smarttime';
+import * as taskbuffer from '@push.rocks/taskbuffer';
 
 export {
   lik,
@@ -30,6 +31,7 @@ export {
   smartunique,
   smartstring,
   smarttime,
+  taskbuffer,
 };
 
 // @tsclass scope

ts/smartacme.classes.smartacme.ts

@@ -4,6 +4,22 @@ import { SmartacmeCertMatcher } from './smartacme.classes.certmatcher.js';
 import { commitinfo } from './00_commitinfo_data.js';
 import { SmartacmeCert } from './smartacme.classes.cert.js';
 
+// ── Types & constants for certificate issuance task ──────────────────────────
+
+interface ICertIssuanceInput {
+  certDomainName: string;
+  domainArg: string;
+  isWildcardRequest: boolean;
+  includeWildcard: boolean;
+}
+
+const CERT_ISSUANCE_STEPS = [
+  { name: 'prepare',   description: 'Creating ACME order',         percentage: 10 },
+  { name: 'authorize', description: 'Solving ACME challenges',     percentage: 40 },
+  { name: 'finalize',  description: 'Finalizing and getting cert', percentage: 30 },
+  { name: 'store',     description: 'Storing certificate',         percentage: 20 },
+] as const;
+
 /**
  * the options for the class @see SmartAcme
  */
@@ -38,6 +54,21 @@ export interface ISmartAcmeOptions {
    * Defaults to ['dns-01'] or first supported type from handlers.
    */
   challengePriority?: string[];
+  /**
+   * Maximum number of concurrent ACME issuances across all domains.
+   * Defaults to 5.
+   */
+  maxConcurrentIssuances?: number;
+  /**
+   * Maximum ACME orders allowed within the sliding window.
+   * Defaults to 250 (conservative limit under Let's Encrypt's 300/3h).
+   */
+  maxOrdersPerWindow?: number;
+  /**
+   * Sliding window duration in milliseconds for rate limiting.
+   * Defaults to 3 hours (10_800_000 ms).
+   */
+  orderWindowMs?: number;
 }
 
 /**
@@ -75,12 +106,21 @@ export class SmartAcme {
   private pendingChallenges: plugins.tsclass.network.IDnsChallenge[] = [];
   // priority order of challenge types
   private challengePriority: string[];
-  // Map for coordinating concurrent certificate requests
+  // TaskManager for coordinating concurrent certificate requests
-  private interestMap: plugins.lik.InterestMap<string, SmartacmeCert>;
+  private taskManager: plugins.taskbuffer.TaskManager;
+  // Single reusable task for certificate issuance
+  private certIssuanceTask: plugins.taskbuffer.Task<undefined, typeof CERT_ISSUANCE_STEPS>;
   // bound signal handlers so they can be removed on stop()
   private boundSigintHandler: (() => void) | null = null;
   private boundSigtermHandler: (() => void) | null = null;
 
+  /**
+   * Exposes the aggregated task event stream for observing certificate issuance progress.
+   */
+  public get certIssuanceEvents(): plugins.taskbuffer.TaskManager['taskSubject'] {
+    return this.taskManager.taskSubject;
+  }
+
   constructor(optionsArg: ISmartAcmeOptions) {
     this.options = optionsArg;
     this.logger = plugins.smartlog.Smartlog.createForCommitinfo(commitinfo);
@@ -105,8 +145,60 @@ export class SmartAcme {
       optionsArg.challengePriority && optionsArg.challengePriority.length > 0
         ? optionsArg.challengePriority
         : this.challengeHandlers.map((h) => h.getSupportedTypes()[0]);
-    // initialize interest coordination
+
-    this.interestMap = new plugins.lik.InterestMap((domain) => domain);
+    // ── TaskManager setup ──────────────────────────────────────────────────
+    this.taskManager = new plugins.taskbuffer.TaskManager();
+
+    // Constraint 1: Per-domain mutex — one issuance at a time per TLD, with result sharing
+    const certDomainMutex = new plugins.taskbuffer.TaskConstraintGroup({
+      name: 'cert-domain-mutex',
+      maxConcurrent: 1,
+      resultSharingMode: 'share-latest',
+      constraintKeyForExecution: (_task, input?: ICertIssuanceInput) => {
+        return input?.certDomainName ?? null;
+      },
+      shouldExecute: async (_task, input?: ICertIssuanceInput) => {
+        if (!input?.certDomainName || !this.certmanager) return true;
+        // Safety net: if a valid cert is already cached, skip re-issuance
+        const existing = await this.certmanager.retrieveCertificate(input.certDomainName);
+        if (existing && !existing.shouldBeRenewed()) {
+          return false;
+        }
+        return true;
+      },
+    });
+
+    // Constraint 2: Global concurrency cap
+    const acmeGlobalConcurrency = new plugins.taskbuffer.TaskConstraintGroup({
+      name: 'acme-global-concurrency',
+      maxConcurrent: optionsArg.maxConcurrentIssuances ?? 5,
+      constraintKeyForExecution: () => 'global',
+    });
+
+    // Constraint 3: Account-level rate limiting
+    const acmeAccountRateLimit = new plugins.taskbuffer.TaskConstraintGroup({
+      name: 'acme-account-rate-limit',
+      rateLimit: {
+        maxPerWindow: optionsArg.maxOrdersPerWindow ?? 250,
+        windowMs: optionsArg.orderWindowMs ?? 10_800_000,
+      },
+      constraintKeyForExecution: () => 'account',
+    });
+
+    this.taskManager.addConstraintGroup(certDomainMutex);
+    this.taskManager.addConstraintGroup(acmeGlobalConcurrency);
+    this.taskManager.addConstraintGroup(acmeAccountRateLimit);
+
+    // Create the single reusable certificate issuance task
+    this.certIssuanceTask = new plugins.taskbuffer.Task({
+      name: 'cert-issuance',
+      steps: CERT_ISSUANCE_STEPS,
+      taskFunction: async (input: ICertIssuanceInput) => {
+        return this.performCertificateIssuance(input);
+      },
+    });
+
+    this.taskManager.addTask(this.certIssuanceTask);
   }
 
   /**
@@ -149,6 +241,10 @@ export class SmartAcme {
       termsOfServiceAgreed: true,
       contact: [`mailto:${this.options.accountEmail}`],
     });
+
+    // Start the task manager
+    await this.taskManager.start();
+
     // Setup graceful shutdown handlers (store references for removal in stop())
     this.boundSigintHandler = () => this.handleSignal('SIGINT');
     this.boundSigtermHandler = () => this.handleSignal('SIGTERM');
@@ -169,6 +265,16 @@ export class SmartAcme {
       process.removeListener('SIGTERM', this.boundSigtermHandler);
       this.boundSigtermHandler = null;
     }
+    // Stop the task manager
+    await this.taskManager.stop();
+    // Destroy ACME HTTP transport (closes keep-alive sockets)
+    if (this.client) {
+      this.client.destroy();
+    }
+    // Destroy DNS client (kills Rust bridge child process if spawned)
+    if (this.smartdns) {
+      this.smartdns.destroy();
+    }
     if (this.certmanager && typeof (this.certmanager as any).close === 'function') {
       await (this.certmanager as any).close();
     }
@@ -247,8 +353,7 @@ export class SmartAcme {
    * * if not in the database announce it
    * * then get it from letsencrypt
    * * store it
-   * * remove it from the pending map (which it go onto by announcing it)
+   * * retrieve it from the database and return it
-   * * retrieve it from the databse and return it
    *
    * @param domainArg
    * @param options Optional configuration for certificate generation
@@ -276,35 +381,59 @@ export class SmartAcme {
     // Retrieve any existing certificate record by base domain.
     const retrievedCertificate = await this.certmanager.retrieveCertificate(certDomainName);
 
-    if (
+    if (retrievedCertificate && !retrievedCertificate.shouldBeRenewed()) {
-      !retrievedCertificate &&
-      (await this.interestMap.checkInterest(certDomainName))
-    ) {
-      const existingCertificateInterest = this.interestMap.findInterest(certDomainName);
-      const certificate = existingCertificateInterest.interestFullfilled;
-      return certificate;
-    } else if (retrievedCertificate && !retrievedCertificate.shouldBeRenewed()) {
       return retrievedCertificate;
     } else if (retrievedCertificate && retrievedCertificate.shouldBeRenewed()) {
       // Remove old certificate via certManager
       await this.certmanager.deleteCertificate(certDomainName);
     }
 
-    // lets make sure others get the same interest
+    // Build issuance input and trigger the constrained task
-    const currentDomainInterst = await this.interestMap.addInterest(certDomainName);
+    const issuanceInput: ICertIssuanceInput = {
+      certDomainName,
+      domainArg,
+      isWildcardRequest,
+      includeWildcard: options?.includeWildcard ?? false,
+    };
+
+    const result = await this.taskManager.triggerTaskConstrained(
+      this.certIssuanceTask,
+      issuanceInput,
+    );
+
+    // If we got a cert directly (either from execution or result sharing), return it
+    if (result != null) {
+      return result;
+    }
+
+    // If shouldExecute returned false (cert appeared in cache), read from cache
+    const cachedCert = await this.certmanager.retrieveCertificate(certDomainName);
+    if (cachedCert) {
+      return cachedCert;
+    }
+
+    throw new Error(`Certificate issuance failed for ${certDomainName}`);
+  }
+
+  /**
+   * Performs the actual ACME certificate issuance flow.
+   * Called by the certIssuanceTask's taskFunction.
+   */
+  private async performCertificateIssuance(input: ICertIssuanceInput): Promise<SmartacmeCert> {
+    const { certDomainName, isWildcardRequest, includeWildcard } = input;
+
+    // ── Step: prepare ─────────────────────────────────────────────────────
+    this.certIssuanceTask.notifyStep('prepare');
 
     // Build identifiers array based on request
-    const identifiers = [];
+    const identifiers: Array<{ type: 'dns'; value: string }> = [];
 
     if (isWildcardRequest) {
-      // If requesting a wildcard directly, only add the wildcard
       identifiers.push({ type: 'dns', value: `*.${certDomainName}` });
     } else {
-      // Add the regular domain
       identifiers.push({ type: 'dns', value: certDomainName });
 
-      // Only add wildcard if explicitly requested
+      if (includeWildcard) {
-      if (options?.includeWildcard) {
         const hasDnsHandler = this.challengeHandlers.some((h) =>
           h.getSupportedTypes().includes('dns-01'),
         );
@@ -321,6 +450,9 @@ export class SmartAcme {
       identifiers,
     }), 'createOrder');
 
+    // ── Step: authorize ───────────────────────────────────────────────────
+    this.certIssuanceTask.notifyStep('authorize');
+
     /* Get authorizations and select challenges */
     const authorizations = await this.retry(() => this.client.getAuthorizations(order), 'getAuthorizations');
 
@@ -344,45 +476,37 @@ export class SmartAcme {
       }
       const { type, handler } = selectedHandler;
       // build handler input with keyAuthorization
-      let input: any;
+      let challengeInput: any;
       // retrieve keyAuthorization for challenge
       const keyAuth = await this.client.getChallengeKeyAuthorization(selectedChallengeArg);
       if (type === 'dns-01') {
-        input = { type, hostName: `_acme-challenge.${authz.identifier.value}`, challenge: keyAuth };
+        challengeInput = { type, hostName: `_acme-challenge.${authz.identifier.value}`, challenge: keyAuth };
       } else if (type === 'http-01') {
-        // HTTP-01 requires serving token at webPath
+        challengeInput = {
-        input = {
           type,
           token: (selectedChallengeArg as any).token,
           keyAuthorization: keyAuth,
           webPath: `/.well-known/acme-challenge/${(selectedChallengeArg as any).token}`,
         };
       } else {
-        // generic challenge input: include raw challenge properties
+        challengeInput = { type, keyAuthorization: keyAuth, ...selectedChallengeArg };
-        input = { type, keyAuthorization: keyAuth, ...selectedChallengeArg };
       }
-      this.pendingChallenges.push(input);
+      this.pendingChallenges.push(challengeInput);
       try {
-        // Prepare the challenge (set DNS record, write file, etc.)
+        await this.retry(() => handler.prepare(challengeInput), `${type}.prepare`);
-        await this.retry(() => handler.prepare(input), `${type}.prepare`);
-        // For DNS-01, wait for propagation before verification
         if (type === 'dns-01') {
-          const dnsInput = input as { hostName: string; challenge: string };
+          const dnsInput = challengeInput as { hostName: string; challenge: string };
-          // Wait for authoritative DNS propagation before ACME verify
           await this.retry(
             () => this.smartdns.checkUntilAvailable(dnsInput.hostName, 'TXT', dnsInput.challenge, 100, 5000),
             `${type}.propagation`,
           );
-          // Extra cool-down to ensure ACME server sees the new TXT record
           this.logger.log('info', 'Cooling down for 1 minute before ACME verification');
           await plugins.smartdelay.delayFor(60000);
         }
-        // Notify ACME server to complete the challenge
         await this.retry(
           () => this.client.completeChallenge(selectedChallengeArg),
           `${type}.completeChallenge`,
         );
-        // Wait for valid status (warnings on staging timeouts)
         try {
           await this.retry(
             () => this.client.waitForValidStatus(selectedChallengeArg),
@@ -396,30 +520,28 @@ export class SmartAcme {
           );
         }
       } finally {
-        // Always cleanup resource
         try {
-          await this.retry(() => handler.cleanup(input), `${type}.cleanup`);
+          await this.retry(() => handler.cleanup(challengeInput), `${type}.cleanup`);
         } catch (err) {
           await this.logger.log('error', `Error during ${type}.cleanup`, err);
         } finally {
-          this.pendingChallenges = this.pendingChallenges.filter((c) => c !== input);
+          this.pendingChallenges = this.pendingChallenges.filter((c) => c !== challengeInput);
         }
       }
     }
 
-    /* Finalize order */
+    // ── Step: finalize ────────────────────────────────────────────────────
-    const csrDomains = [];
+    this.certIssuanceTask.notifyStep('finalize');
+
+    const csrDomains: string[] = [];
     let commonName: string;
 
     if (isWildcardRequest) {
-      // For wildcard requests, use wildcard as common name
       commonName = `*.${certDomainName}`;
-      csrDomains.push(certDomainName); // Add base domain as alt name
+      csrDomains.push(certDomainName);
     } else {
-      // For regular requests, use base domain as common name
       commonName = certDomainName;
-      if (options?.includeWildcard && identifiers.some(id => id.value === `*.${certDomainName}`)) {
+      if (includeWildcard && identifiers.some(id => id.value === `*.${certDomainName}`)) {
-        // If wildcard was successfully added, include it as alt name
         csrDomains.push(`*.${certDomainName}`);
       }
     }
@@ -432,9 +554,9 @@ export class SmartAcme {
     await this.retry(() => this.client.finalizeOrder(order, csr), 'finalizeOrder');
     const cert = await this.retry(() => this.client.getCertificate(order), 'getCertificate');
 
-    /* Done */
+    // ── Step: store ───────────────────────────────────────────────────────
+    this.certIssuanceTask.notifyStep('store');
 
-    // Store the new certificate record
     const certRecord = new SmartacmeCert({
       id: plugins.smartunique.shortId(),
       domainName: certDomainName,
@@ -447,9 +569,7 @@ export class SmartAcme {
     await this.certmanager.storeCertificate(certRecord);
 
     const newCertificate = await this.certmanager.retrieveCertificate(certDomainName);
-    currentDomainInterst.fullfillInterest(newCertificate);
+    return newCertificate ?? certRecord;
-    currentDomainInterst.destroy();
-    return newCertificate;
   }
 
 }