[Polkadot/Kusama/Westend] Sidecar API Deprecation Notice

Scheduled for Aug 24, 10:00 - 12:00 UTC

Scheduled

Parity, the maintainer of the Polkadot SDK, is deprecating the Substrate API Sidecar (substrate-api-sidecar)—the service that currently sits in front of Polkadot and Kusama nodes to simplify node access. It has been replaced by the Polkadot REST API, a rebuilt successor that offers the same core functionality.

As a result, Blockdaemon will remove the Sidecar API from our dedicated nodes and API effective August 24, 2026. After this date, requests to the Sidecar endpoint will no longer be served.

What you need to do

The Polkadot REST API is broadly compatible with Sidecar, but the endpoint structure and some response formats differ. We recommend that you:

Review the Polkadot REST API documentation and migration guide, and test it against your specific use cases before the cutover date.
Migration Guide: https://github.com/paritytech/polkadot-rest-api/blob/main/docs/guides/MIGRATION.md
Update any integrations that currently reference the Sidecar endpoint.

References:

https://docs.blockdaemon.com/docs/how-to-connect-to-polkadot#4-how-to-connect-via-rest-api
https://docs.blockdaemon.com/docs/polkadot-via-polkadot-rest-api

We're here to help

Your Customer Success Manager is available to walk through the migration and discuss your specific setup, or you can reach our Support Team directly at support@blockdaemon.com.

Posted Aug 07, 2026 - 09:36 UTC

This scheduled maintenance affects: Blockdaemon Universal API, Blockdaemon RPC API (Kusama Native API, Polkadot Native API), and Protocols (Dedicated Nodes) (Kusama, Polkadot).