---
title: "Run sync pipeline (read → write)"
method: POST
path: "/pipeline_sync"
tags: ["Stateless Sync API"]
---

# Run sync pipeline (read → write)

`POST /pipeline_sync`

Without a request body, reads from the source connector and writes to the destination (backfill mode). With an NDJSON request body, uses the provided messages as input instead of reading from the source (push mode — e.g. piped webhook events).

## Query parameters

- `state_limit` integer — Stop streaming after N state messages.
- `time_limit` number — Stop streaming after N seconds.

## Response `200`

NDJSON stream of sync messages

## Other responses

- `400` — Invalid params

## Changes

- **2026-04-15** `4e5abb8c5e22` — 2 breaking
  - removed the media type `application/json` from the request body
  - the `header` request parameter `x-pipeline` became required
- **2026-04-15** `2e101196e4f5` — 2 info
  - added the media type `application/json` to the request body
  - the `header` request parameter `x-pipeline` became optional
- **2026-04-14** `4e5abb8c5e22` — 8 warning, 2 info
  - added the new `auth_error` enum value to the `oneOf[#/components/schemas/EofMessage]/eof/stream_progress/additionalProperties/status` response property for the response status `200`
  - added the new `auth_error` enum value to the `oneOf[#/components/schemas/TraceMessage]/trace/oneOf[subschema #2]/stream_status/status` response property for the response status `200`
  - added the new `config_error` enum value to the `oneOf[#/components/schemas/EofMessage]/eof/stream_progress/additionalProperties/status` response property for the response status `200`
  - added the new `config_error` enum value to the `oneOf[#/components/schemas/TraceMessage]/trace/oneOf[subschema #2]/stream_status/status` response property for the response status `200`
  - …6 more
- **2026-04-14** `fe381b9ff4bd` — 1 warning
  - removed the optional property `oneOf[#/components/schemas/ControlMessage]/control/oneOf[subschema #1]/source_config/backfill_concurrency` from the response with the `200` status
- …earlier changes not shown

[Full history](https://skmtc.dev/stripe/apis/stripe-sync-engine/changes/pipeline_sync/post.md)

---

[API](https://skmtc.dev/stripe/apis/stripe-sync-engine.md) · [All operations](https://skmtc.dev/stripe/apis/stripe-sync-engine/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/stripe/stripe-sync-engine/revisions/4e5abb8c5e22/schema)