Open source alternatives to GPT-6 Luna

Bonsai 27B is listed first. Choose Bonsai 27B when cheap, high-volume text work has to run on your own machine rather than on OpenAI's metered API.

Yes. The code of all 4 is public under Apache 2.0, MIT or OpenMDW 1.1, so you can use them with no licence fee. Running one yourself costs the server and your time to look after it, and some makers also sell a hosted plan.

Start from the job you use GPT-6 Luna for. Choose DeepSeek V4.1 Flash when you want MIT-licensed weights you can run yourself, replies up to 384K tokens, or cheaper cache reads on DeepSeek's API. Choose MiMo-V2.6-Flash when you want open weights to self-host, or Xiaomi's low-cost pay-as-you-go API, for agent work.

All 4: Bonsai 27B, DeepSeek V4.1 Flash, MiMo-V2.6-Flash and Nemotron 3.5 Lightning. Each tool's page says what it needs to run.

MIT (2), Apache 2.0 (1), OpenMDW 1.1 (1). MIT, BSD and Apache let you change and reuse the code freely.

The hosting. GPT-6 Luna's maker runs the servers for you; with an open source tool the updates, backups, security fixes and support are yours, unless you take the maker's hosted plan. Features differ too, so check what each one imports and exports before you move your data.