Sim Studio

Sim is an open-source platform where you connect blocks on a canvas to create AI agent workflows. Blocks cover models, tools, conditions, APIs and knowledge bases, and a chat panel lets you test the whole flow.

You can self-host it or use the hosted version, and it integrates with many common services. The visual approach makes it easier to explain an agent's logic to teammates.

It is newer than competitors such as Dify and n8n, so the ecosystem is smaller. If you like the visual style, it is worth trying.