All packsWebhook Durability & ReplaySolve
webhook dead letter replay vs reprocessing re-ingestion
Replay is re-processing, never a second ingestion path
Replaying a dead delivery resets it to pending and runs it through the exact same pipeline -- the same handlers, watermark and ledger -- rather than a separate 'reprocess' code path (D12).
This is one of the things Webhook Durability & Replay already handles. Receive webhooks without losing, duplicating or misordering them when the sender retries.
Is this you?
Building a dedicated 'reprocess this dead event' function that re-applies its effect directly, bypassing the normal pipeline, creates a second code path with its own bugs -- one that can double-apply an effect that actually did land before the delivery was marked dead, since it skips the ledger check the normal path would have run.
Why this one is easy to get wrong
A dead row feels like a special case that needs its own recovery function -- write a small script that reads the dead row and does whatever the handler would have done. That instinct misses that the existing pipeline already handles "has this effect already landed" correctly, and a bespoke reprocessing path has to re-derive that same safety from scratch.
What you get instead
replayDead() does nothing but reset matching dead rows to pending, attempts = 0, next_attempt_at = now(), source = 'replay' -- it never re-inserts and never bypasses processDelivery. A replayed row whose effect already landed is simply a ledger no-op; one whose effect never landed applies it normally, through the identical handlers, watermark, and ledger every other delivery goes through.
Source: ARCHITECTURE.md D12 — checkable in the pack you receive
How you actually use this
You don’t install a library or wire up an SDK. Your own coding agent builds the code in your project, and you keep it — no runtime dependency on us.
Step 1
Download and unzip
You get a folder: the docs that tell an agent what to build, a starting skeleton, and the test suite that decides when it's done.
Step 2
Open it in Claude Code or Cursor
Point your coding agent at the folder. Nothing to install, no account with us, no API key.
Step 3
Paste one prompt
The pack contains the exact prompt. Paste it as your first message and leave it alone — it works through the build itself, choosing a cheaper or stronger model per task.
Step 4
Run ./verify.sh
One command. It prints a pass or fail for every check. Green means the build is done — the same script we ran to produce the receipt on this page.
Typical build: about 40 minutes of your agent working, mostly unattended. Then you integrate the working module into your app the way you would any code you’d written yourself.
Why you can believe this
3 of 3 runs passedWe ran this pack from an empty folder 3 times and published exactly what happened — every check, the model, the token cost, the wall time. Not a testimonial, and not our opinion: the same verify.sh you run yourself. Read the full receipt →