Maxwell's Daemon vs pgstream

Maxwell's Daemon is a free, open-source, self-hosted Linux tool for moving MySQL changes into streaming systems. It reads MySQL binary logs and emits database changes as JSON for Kafka, Kinesis, SQS, SNS, NATS, Google Cloud Pub/Sub, BigQuery, RabbitMQ, Redis, and other destinations. Listed uses include ETL, database change auditing, cache building or expiration, search indexing, and communication between services. Filtering can select databases, tables, and column values, while JavaScript filters handle custom row filtering and data changes. When encryption is enabled, messages use AES/CBC/PKCS5PADDING with a user-provided key and base64-encoded values. Metrics can be exposed through logging, JMX, HTTP, or Datadog; HTTP endpoints cover metrics, Prometheus, health checks, ping, and diagnostics. Maxwell supports schema evolution and an initial snapshot. Deployment options include command line, Docker, binary distribution, and Homebrew. Requirements include JRE 11 or later, supported MySQL versions from 5.1 through 8, and Kafka 0.8.2 or later when Kafka is used.

pgstream is a free, open-source tool for moving PostgreSQL data and schema changes to other systems. Run it as a command-line program or embed it as a Go library; it is self-hosted and requires PostgreSQL. Destinations include PostgreSQL, Elasticsearch or OpenSearch, Kafka, and webhooks. It can take an initial or on-demand snapshot for bulk loads and point-in-time copies, and tracks schema changes so receiving systems can reflect table updates. During replication, column values can be transformed with greenmask, neosync, go-masker, or custom transformers, including to mask production data headed for development or staging. Kafka support includes schema-based partitioning. Installation options include a Go binary, building from source, and Homebrew on macOS or Linux. The project uses the Apache License 2.0 and costs nothing. Its initial release has constraints: one Kafka topic, the wal2json PostgreSQL plugin, no row-level filtering, and a primary-key or unique non-null column requirement. Community questions and issues go through GitHub issues.