Sim

Sim, from Sim Studio AI, is an open-source (29.5k+ GitHub stars, SOC 2 compliant) platform for building and deploying AI agents, trusted by 100,000+ builders including Rivian/Volkswagen Group and eXp Realty. Agents are built with a visual, connected-block workflow editor or described in plain English, and can draw on 1,000+ integrations (Slack, Salesforce, HubSpot, Notion, GitHub) plus semantic knowledge storage across tables, files, and knowledge bases. Live logs and cost tracking give visibility into exactly what each agent decision cost and why, and it runs on every major LLM rather than locking you into one provider. Exact pricing isn't published on the main site — there's a dedicated pricing page, and being open source means self-hosting is a genuine zero-cost option for teams willing to run their own infrastructure. Good fit for a team that wants to build multi-step AI agent workflows visually without being locked into a single model provider or a fully closed platform.