head to head · open source
OpenViking vs nebula
OpenViking has 40,758 GitHub stars, 3,300 forks, 999 open issues and last shipped 2 days ago. nebula has 12,451 stars, 1,340 forks, 678 open issues and last shipped 2 months ago. OpenViking leads on adoption by 227% (40,758 vs 12,451 stars). OpenViking is written in Python under AGPL-3.0; nebula is written in C++ under Apache-2.0. OpenViking has attracted 8% as many forks as stars, nebula 11%. OpenViking was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 1 topic tag (knowledge-base), 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
| OpenViking | nebula | |
|---|---|---|
| GitHub stars | ★ 41K | ★ 12K |
| License | AGPL-3.0 | Apache-2.0 |
| Written in | Python | C++ |
| Last push | 2026-10-24 | 2026-09-08 |
| Forks | ⑂ 3.3K | ⑂ 1.3K |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick OpenViking if
- You weight community size — 41K stars and counting
- You want the AGPL-3.0 license terms
- Your stack matches Python
- You value the larger contributor base for long-term maintenance
pick nebula if
- You want the nebula feature set and don't need the biggest community
- You prefer the Apache-2.0 license terms
- Your stack matches C++
- You evaluated both and nebula fits your workflow better
About OpenViking
The Context Database for AI Agents English / 中文 / 日本語 Website · Live Demo · GitHub · Issues · Docs · Blog Lark · WeChat · Discord · X What is OpenViking OpenViking is an open source context database for AI agents — one filesystem for everything an agent knows: knowledge, memory, and skills. Most agent memory is a black box: text goes in, embeddings come out, and nobody can see what was actually stored. OpenViking organizes context as a virtual filesystem under viking:// instead. Agents navigate it like files — ls , tree , read , write , grep — and you can open any directory to inspect and edit what your agent…
read the full OpenViking overview →
About nebula
English 中文 A distributed, scalable, lightning fast graph database NebulaGraph Introduction NebulaGraph is a popular open source graph database that can handle large volumes of data with milliseconds of latency, scale up quickly, and have the ability to perform fast graph analytics. NebulaGraph has been widely used for social media, recommendation systems, knowledge graphs, security, capital flows, AI, etc. See our users. The following lists some of NebulaGraph features: Symmetrically distributed Storage and computing separation Horizontal scalability Strong data consistency by RAFT protocol OpenCypher compatible…
read the full nebula overview →
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Frequently asked questions
Is OpenViking or nebula more popular?
OpenViking has 40,758 GitHub stars and nebula has 12,451. OpenViking has the larger community by that measure.
Are OpenViking and nebula free?
Both are open source. OpenViking is licensed under AGPL-3.0 and nebula under Apache-2.0. Neither carries a licence fee.
What is the difference between OpenViking and nebula?
OpenViking is written in Python and nebula in C++. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, OpenViking or nebula?
Choose OpenViking if you want the larger community (40,758 stars) or its AGPL-3.0 licence terms. Choose nebula if its feature set, stack or Apache-2.0 licence fits better. Both are self-hostable.