head to head · open source
zvec vs rag_api
zvec has 15,972 GitHub stars, 998 forks, 56 open issues and last shipped today. rag_api has 901 stars, 404 forks, 45 open issues and last shipped 1 months ago. zvec leads on adoption by 1,673% (15,972 vs 901 stars). zvec is written in C++ under Apache-2.0; rag_api is written in Python under MIT. zvec has attracted 6% as many forks as stars, rag_api 45%. zvec was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (rag), 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
| zvec | rag_api | |
|---|---|---|
| GitHub stars | ★ 16K | ★ 901 |
| License | Apache-2.0 | MIT |
| Written in | C++ | Python |
| Last push | 2026-09-20 | 2026-08-15 |
| Forks | ⑂ 998 | ⑂ 404 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick zvec if
- You weight community size — 16K stars and counting
- You want the Apache-2.0 license terms
- Your stack matches C++
- You value the larger contributor base for long-term maintenance
pick rag_api if
- You want the rag_api feature set and don't need the biggest community
- You prefer the MIT license terms
- Your stack matches Python
- You evaluated both and rag_api fits your workflow better
About zvec
Zvec is an open source, in process vector database written in C++ and licensed under Apache 2.0, built to embed directly into applications so that vector search, full text search, and hybrid retrieval run inside the developer's own process instead of behind a separate service.
About rag_api
rag api is an MIT licensed Python FastAPI service that indexes documents into embeddings by file id and serves ID based retrieval augmented generation over Langchain and PostgreSQL/pgvector, built primarily for LibreChat deployments but usable by any application that stores embeddings at the file level.
read the full rag_api overview →
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Frequently asked questions
Is zvec or rag_api more popular?
zvec has 15,972 GitHub stars and rag_api has 901. zvec has the larger community by that measure.
Are zvec and rag_api free?
Both are open source. zvec is licensed under Apache-2.0 and rag_api under MIT. Neither carries a licence fee.
What is the difference between zvec and rag_api?
zvec is written in C++ and rag_api in Python. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, zvec or rag_api?
Choose zvec if you want the larger community (15,972 stars) or its Apache-2.0 licence terms. Choose rag_api if its feature set, stack or MIT licence fits better. Both are self-hostable.