Transforms

Transforms allow you to modify the structure of your messages before they are sent to the sink destination. This is useful for:

• Simplifying message payloads to reduce bandwidth and storage costs
• Extracting specific fields from complex message structures
• Maintaining compatibility with different sink destinations
• Keeping payloads under size limits (e.g., SQS 256KB limit)

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Available transform types

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Path transform (Current)

The path transform allows you to extract a specific field from your message using a dot-notation path. This is particularly useful for:

1. Sending just the latest record to the destination (e.g., for materialized views in Postgres or data warehouses)
2. Extracting just the record ID to keep payloads small (e.g., for SQS with its 256KB limit)

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Path syntax

Paths follow a dot-notation format to traverse the message structure. Valid paths start with:

• record - The record object
• changes - The changes object
• action - The action type (insert, update, delete)
• metadata - The metadata object

Paths can be as deep as you need them to be. For example, record.id will extract the id field from the record object and record.address.city will extract the city field from the address object in the record object.

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Coming soon

• Code transform: Write custom Lua code to transform your messages
• Webhook transform: Send messages to a webhook for transformation before delivery

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Testing transforms

When creating or editing a transform, Sequin will automatically capture up to 10 recent events from your database. You can see how your transform affects these events in real-time.

When changes occur in a connected database and you have the transform editor open, Sequin will capture events and display them in the editor:

This live preview helps ensure your transform will work correctly with your actual data.

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Example use cases

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Keeping payloads small

When using SQS (which has a 256KB payload limit), you can use a path transform to extract just the record ID:

transform:
  path: record.id

Your consumer can then query the full record details as needed.

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Maintaining Debezium-like format

For systems expecting a Debezium-like format, use a path transform to extract just the record:

transform:
  path: record

This ensures your messages match the expected format without additional metadata.

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