Open source alternatives to Claude Sonnet 5

Command A+ is listed first. Choose Command A+ when agent workloads must run inside your own environment, with free downloadable weights instead of a hosted API.

Yes. The code of all 3 is public under Apache 2.0 or MIT, 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 Claude Sonnet 5 for. Choose GLM-4.7 when you want an MIT-licensed agentic coding model with a 200K context that you can self-host. Choose LongCat-2.0 when you want an MIT-licensed 1.6T MoE model with a 1M-token context for coding that you can self-host.

All 3: Command A+, GLM-4.7 and LongCat-2.0. Each tool's page says what it needs to run.

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

The hosting. Claude Sonnet 5'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.