head to head · open source
realtime vs flink-cdc
realtime has 7,635 GitHub stars, 468 forks, 78 open issues and last shipped 2 days ago. flink-cdc has 6,477 stars, 2,197 forks, 119 open issues and last shipped 2 days ago. realtime leads on adoption by 18% (7,635 vs 6,477 stars). realtime is written in Elixir under Apache-2.0; flink-cdc is written in Java under Apache-2.0. realtime has attracted 6% as many forks as stars, flink-cdc 34%. realtime was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 2 topic tags (cdc, change-data-capture), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| realtime | flink-cdc | |
|---|---|---|
| GitHub stars | ★ 7.6K | ★ 6.5K |
| License | Apache-2.0 | Apache-2.0 |
| Written in | Elixir | Java |
| Last push | 2026-09-18 | 2026-09-18 |
| Forks | ⑂ 468 | ⑂ 2.2K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick realtime if
- You weight community size — 7.6K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches Elixir
- You value the larger contributor base for long-term maintenance
pick flink-cdc if
- You want the flink-cdc feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches Java
- You evaluated both and flink-cdc fits your workflow better
About realtime
Supabase Realtime is a server built with Elixir on the Phoenix Framework that pushes three kinds of realtime functionality to browser and server clients over WebSockets. It lives in the Supabase ecosystem, where it acts as the realtime layer alongside Postgres, and it is distributed as open source under the Apache 2.0 license. The project has been public for roughly seven years, carries 7,632 stars and 463 forks, and its topic list places it in the company of change data capture, CRDT, distributed systems, pubsub, and PostgreSQL tooling.
read the full realtime overview →
About flink-cdc
Flink CDC is an Apache 2.0 streaming data integration tool built on Apache Flink that moves real time and batch data between databases and downstream systems, and it is aimed at data engineers and platform teams who need change data capture pipelines without writing per source job code.
read the full flink-cdc overview →
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Frequently asked questions
Is realtime or flink-cdc more popular?
realtime has 7,635 GitHub stars and flink-cdc has 6,477. realtime has the larger community by that measure.
Are realtime and flink-cdc free?
Both are open source. realtime is licensed under Apache-2.0 and flink-cdc under Apache-2.0. Neither carries a licence fee.
What is the difference between realtime and flink-cdc?
realtime is written in Elixir and flink-cdc in Java. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, realtime or flink-cdc?
Choose realtime if you want the larger community (7,635 stars) or its Apache-2.0 licence terms. Choose flink-cdc if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.