> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.merge.dev/merge-unified/writing-data/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.merge.dev/_mcp/server.

# Writing data

> Build once. Connect to every API, tool, and LLM. Ship products and agents to production without owning the integration stack.

## Docs

- [Overview](https://docs.merge.dev/merge-unified/writing-data/overview.md): Overview of writing data through Merge. Links to guides on POST/PATCH requests, the /meta endpoint, related writes, nested writes, and conditional fields.
- [Writes](https://docs.merge.dev/merge-unified/writing-data/writes/introduction.md): How to create and update records in third-party platforms via POST and PATCH requests to Merge's Unified API.
- [Related and Nested Writes](https://docs.merge.dev/merge-unified/writing-data/writes/nested.md): How to create records that reference existing objects (related writes) or create parent and child objects in a single request (nested writes).
- [Async operations](https://docs.merge.dev/merge-unified/writing-data/writes/async-operations.md): How to use Merge's async write endpoints to create records without blocking. Covers polling for completion and handling async response statuses.
- [Idempotency](https://docs.merge.dev/merge-unified/writing-data/writes/idempotency.md): How to use the Idempotency-Key header to safely retry POST requests without creating duplicate records.
- [Programmatic Writes with /meta](https://docs.merge.dev/merge-unified/writing-data/programmatic-writes-with-meta/introduction.md): How to use the /meta endpoint to discover required and optional fields before making a POST request. Fields vary by integration and Linked Account.
- [Programmatic Nested Writes with /meta](https://docs.merge.dev/merge-unified/writing-data/programmatic-writes-with-meta/nested.md): How to use the /meta endpoint to build nested write requests that create multiple related objects in one call, with integration-specific field handling.
- [Templates and Conditional Fields](https://docs.merge.dev/merge-unified/writing-data/programmatic-writes-with-meta/templates-and-conditional-fields.md): How to handle dynamic form fields where available options depend on the value of another field, using /meta endpoint templates.
- [Troubleshooting Writes](https://docs.merge.dev/merge-unified/writing-data/troubleshooting-writes/troubleshooting-tools.md): Tools and techniques for debugging failed write requests, including the Merge Dashboard audit log and API response diagnostics.
- [Writes warnings and errors reference](https://docs.merge.dev/merge-unified/writing-data/troubleshooting-writes/warnings-and-errors-reference.md): Reference table of warning and error codes returned by POST endpoints, with causes and resolution steps.