# Inngest v1.39.0

- Product: Inngest (https://whatsnew.fyi/product/inngest)
- Vendor: Inngest
- Date: 2026-07-28
- Version: v1.39.0
- Original notes: https://github.com/inngest/inngest/releases/tag/v1.39.0
- Permalink: https://whatsnew.fyi/product/inngest/releases/v1.39.0

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

---

- **added** — Add cancel run to the v2 REST API and CLI with POST /api/v2/runs/{run_id}/cancel
- **added** — Add REST v2 rerun from step endpoint POST /v2/runs/{run_id}/rerun with fromStep payload support
- **added** — Augment incoming AI metadata with cost estimates
- **fixed** — Improve CLI timestamp argument handling
- **fixed** — Use snapshots to handle map race access
- **fixed** — Skip constraint lease on missing account
- **fixed** — Fix race condition when creating workflow and checkpointing durable endpoint step
- **fixed** — Recover from panics in event lifecycle listeners
- **changed** — Add shard scanner boundary to queue refactoring
- **changed** — Add scanner runtime to queue refactoring with updated Run signature and LeaseItem/ProcessItem interfaces
- **changed** — Expose available worker count in queue
- **added** — Add logging middleware for API
- **changed** — Make cancellation deadline configurable
- **added** — Add primitives for cross-backend run state migration

##### Release Notes

- [#4638](https://github.com/inngest/inngest/pull/4638) feat(api): v2 api cancel run

  Adds cancel run to the  v2 rest api and cli.

  `POST /api/v2/runs/{run_id}/cancel`

  `inngest api POST /api/v2/runs/{run_id}/cancel`

- [#4645](https://github.com/inngest/inngest/pull/4645) feat(api): rest v2 rerun from step

  `POST /v2/runs/{run_id}/rerun`

  with payload:
  ```json
  {
    "fromStep": {
      "stepId": "fetch-user",
      "input": [
        {
          "userId": "user_123"
        }
      ]
    }
  }
  ```

  CLI equivalent:
  ```
  inngest api --prod rerun <run_id> \
    --from-step "step 2" \
    --input '[{"foo":"bar"}]'
  ```

##### Migration Notes

- [#4655](https://github.com/inngest/inngest/pull/4655) refactor(queue): add shard scanner boundary

  None

  ## Validation

  - go test -count=1 ./pkg/execution/queue
  - go test -run '^$' ./pkg/execution/state/redis_state

- [#4665](https://github.com/inngest/inngest/pull/4665) refactor(queue): add scanner runtime

  Out-of-tree queue scanner implementations must update `Run(ctx, dispatch)` to `Run(ctx, runtime)`, use `runtime.Dispatch` to submit leased work, and may inspect `runtime.WorkerSemaphore` before scanning. Implementations that call `DispatchFunc` must handle the returned `DispatchedItem`; callers may ignore it, or wait on `Done()` with context cancellation or a timeout.

  Callers of `LeaseItem` must stop passing queue partitions and instead provide item metadata on `LeaseItemRequest`. Callers of `ProcessItem` must handle the new `(ProcessItemResult, error)` return shape.

  ## Validation

  - `go test ./pkg/execution/queue`
  - `go test ./tests/execution/queue`
  - `make lint`

- [#4672](https://github.com/inngest/inngest/pull/4672) fix(executor): recover from panics in event lifecycle listeners

  ## Test Plan

  Added `TestRunEventLifecyclesRecoversFromListenerPanic` which verifies that:
  - A panicking listener is called and its panic is recovered
  - Subsequent listeners are still called despite the panic
  - Multiple invocations of `runEventLifecycles` work correctly even after a panic

  https://claude.ai/code/session_01P33HC2LRVTGmbdkEwUYEMu

##### Changelog

###### 🚀 Features

- *(api)* Rest v2 rerun from step (#4645)
- *(metadata)* Augment incoming ai metadata with cost estimates (#4661)
- *(api)* V2 api cancel run (#4638)

###### 🐛 Bug Fixes

- *(cli)* Improve cli timestamp arg handling (#4650)
- Use snapshots to handle map race access (#4653)
- *(queue)* Skip constraint lease on missing account (#4604)
- Race creating workflow and checkpointing durable endpoint step (#4668)
- *(executor)* Recover from panics in event lifecycle listeners (#4672)

###### 🚜 Refactor

- *(queue)* Add shard scanner boundary (#4655)
- *(queue)* Add scanner runtime (#4665)
- *(queue)* Expose available worker count (#4666)

###### ⚙️ Miscellaneous Tasks

- *(logging)* Add logging middleware for API (#4646)
- Make cancellation deadline configurable (#4659)
- *(state)* Add primitives for cross-backend run state migration (#4654)