Anthropic is the AI company behind the Claude family of models, accessed through Anthropic's API or hosted apps like claude.ai. The models themselves are proprietary and closed-weight, and building on Anthropic's API means your application logic and model access depend on Anthropic's hosted infrastructure and pricing.
Dify is worth a look if what you actually want is an open-source application layer for building on top of LLMs — including Anthropic's own models via API — with visual workflows, RAG, and agent tooling you can self-host instead of building from scratch.
FAQ
Is there a free, open-source alternative to Anthropic's platform tooling?
Dify is open source (Apache-2.0 with additional conditions) and self-hostable, though note it's an application-building layer that can still call Anthropic's models via API — it's not a replacement for the models themselves.
What's the best open-source alternative to Anthropic's app-building tools?
Dify is the strongest pick if you want a self-hosted platform for building LLM apps, agents, and RAG pipelines that can connect to Anthropic's or other providers' models.
What are the top open-source alternatives to Anthropic's platform tooling?
Browse all open-source alternatives to Anthropic above, or explore the full Developer Tools category for more options.