Apache Flink CDC

Apache Flink CDC is an open-source data integration tool for capturing changes and moving data through Apache Flink. It is best for teams already prepared to operate Flink that need both configurable pipelines and programmable CDC applications. Its flexible APIs and broad connector set are strong assets, but they come with self-hosted operating responsibilities.

Overview

Flink CDC handles real-time and batch integration, with full database and sharded-table synchronization, log-based capture, and initial snapshots. Schema evolution and transformation support suit ongoing replication as well as data movement into downstream systems. Deployment is on-premise: download Flink CDC and connector JARs, then run them with an Apache Flink deployment. That offers control over the runtime, but teams must provide and maintain it themselves.

Key features

Pipeline and application APIs

The YAML Pipeline API lets teams specify sources, sinks, routing, transformations, and schema evolution rules declaratively. It is a good fit for repeatable pipeline definitions; SQL and DataStream APIs instead support defining CDC sources and building custom Flink streaming applications, for teams that need code-level control.

Connector coverage and compatibility

Pipeline connectors include Doris, Elasticsearch, Fluss, Hudi, Iceberg, Kafka, MaxCompute, MySQL, OceanBase, Oracle, Paimon, PostgreSQL, and StarRocks. SQL and DataStream source connectors include MySQL, PostgreSQL, Oracle, SQL Server, MongoDB, OceanBase, TiDB, Db2, and Vitess. This breadth gives teams options across source databases and destination systems, though they should check that a needed connector and runtime combination fits their deployment.

Flink CDC 3.6 is compatible with Flink 1.20 and 2.2. Version 3.6.0 is built on JDK 11 and requires JDK 11 or later, so matching the Flink version and Java runtime is part of deployment planning. The project directs support questions to its user mailing list and problems to Flink JIRA.

Pricing

Apache Flink CDC is free and open source under the Apache 2.0 License. The Apache Flink CDC plan costs nothing and includes released JARs and connectors. There is no paid tier or trial to weigh against the free option; the cost tradeoff is that teams run the software in their own environment.

Platforms

Flink CDC supports Linux, macOS, and Windows, with self-hosted deployment. Its on-premise model is suited to organizations that want to run CDC within their own infrastructure, rather than rely on a hosted service.

Who it's for

Choose Flink CDC if your team can operate Apache Flink and wants to define data movement through YAML, SQL, or DataStream APIs. Full database and sharded-table synchronization, transformation, and schema evolution make it useful for varied replication jobs. It is a poor fit if you need a managed service or want to avoid maintaining a Flink deployment.

Pros and cons

• Pro: Multiple APIs accommodate declarative pipelines as well as custom Flink applications.
• Pro: Broad source and pipeline connector coverage supports a range of database and sink combinations.
• Pro: The Apache 2.0 license means no software fee for the released JARs and connectors.
• Con: Self-hosted deployment requires teams to run and maintain Apache Flink and its compatible runtime.
• Con: Flink and JDK compatibility must be checked for the version being deployed.

Alternatives

Canal is another free, open-source option for teams seeking CDC software across Linux, macOS, or self-hosted environments.

pgstream is free and open source on Linux, macOS, and self-hosted platforms; consider it as another CDC option.

dbmazz offers a free self-hosted option, including a CLI and terminal dashboard, local web UI, and community support.

Estuary is a freemium alternative with API, web, and self-hosted platforms, a free plan, and a $100.00 USD monthly pay-as-you-go plan; it also offers a free trial.

Striim offers freemium access across API, web, and self-hosted platforms, with a developer plan capped at 25 million events per month and a free trial.

TiCDC is a free option for teams looking for open-source CDC software across API, Linux, macOS, and self-hosted platforms.

Decodable has a free plan with 20 streams, four running tasks, and 24 hours or 10GiB of stream retention; choose it if those stated limits suit your needs and you want a web or API option.

PeerDB offers a free open-source plan aimed at individuals, with Docker setup and CDC, streaming query, and query layer features, plus a free trial.

Browse more options in Change Data Capture Software or compare licensing-focused tools in Open Source License Compliance Software.

Verdict

Apache Flink CDC is a strong choice for teams that already operate Flink and need flexible ways to synchronize and transform database changes without a software license fee. Its main reason to look elsewhere is operational: a self-hosted Flink deployment and compatible JDK are prerequisites, not optional extras.