Google Cloud Datastream vs Sequin

Google Cloud Datastream is a serverless change data capture and replication service for synchronizing data. Streams can capture ongoing updates and backfill historical records, while the service scales automatically without resources for users to provision or manage. Supported destinations include BigQuery, Cloud Storage, and Apache Iceberg tables. Documented sources include Oracle, MySQL, PostgreSQL, AlloyDB, SQL Server, MongoDB, Spanner, Salesforce, ServiceNow, Workday, and Microsoft Dataverse; some sources are marked as preview. Datastream can work with Dataflow templates to load data from Cloud Storage into destinations including BigQuery, Cloud SQL, and Spanner. Connectivity options include IP allowlisting, a forward SSH tunnel, and private connectivity over VPC peering. Processing is charged, idle streams incur no cost, and other Google Cloud resources are billed separately. The free tier includes 100 GiB of eligible CDC data per month per billing account. Events are delivered at least once, but ordering is not guaranteed. Datastream is administered through the Google Cloud console, CLI, or REST API.

Sequin streams changes from PostgreSQL to destinations such as Kafka, Redis, queues, search indexes, and webhooks. It runs as a Docker image alongside the database and can be started with Docker Compose, so deployment is self-hosted. Users can filter and transform changes, add data from Postgres, and route results to destinations including AWS SQS, GCP Pub/Sub, NATS, Elasticsearch, Typesense, and Meilisearch. Backfills can start at the beginning of a table or a chosen point, and can replay selected rows. Sequin describes delivery as using automatic retries, exponential backoff, strict ordering, and exactly-once processing. Sinks can be managed through a console, CLI, YAML configuration, or API. Monitoring includes a Prometheus metrics endpoint and Grafana dashboard. PostgreSQL 14 or later is supported; versions 12 and 13 have limitations. Sequin is open source under the MIT license, with a listed self-hosted plan at free. Sequin Cloud shut down on October 23, 2025; the project continues in maintenance mode with security patches and critical bug fixes.