Langflow vs Sim

Langflow

Langflow is the visual layer most teams reach for when a flow needs to be shown to someone who does not write Python, and the escape hatch into real code keeps it from becoming a toy. Deploying a flow as an API or MCP server in one step is the feature that earns it a place in production. The gap is commercial: no published pricing, no named vendor on the site, and support only via a contact form.

Pros

• +MIT-licensed with roughly 154,000 GitHub stars and an active release cadence
• +Any flow deploys as an HTTP API or an MCP server
• +Runs identically self-hosted, in the free cloud, or as a desktop app
• +Components can be edited as Python when the visual layer runs out

Cons

• −No pricing or support tiers published anywhere on the site
• −Desktop download requires a signup form and covers only Mac and Windows
• −The site names no operating company or jurisdiction
• −Visual flows get hard to reason about once they grow past a screen

Sim

Sim covers the unglamorous half of agent work — memory, tables, file storage, logs — in the same place you draw the workflow, and the open repository means you can host it yourself if the meter bothers you. The meter is the catch: credits are the unit of everything, and an agent that loops or fans out consumes them faster than the per-seat headline suggests.

Pros

• +Three ways to build the same agent: visual canvas, chat, or code
• +Ships knowledge bases, data tables and file storage alongside the workflow engine
• +Open source on GitHub with a documented self-hosting route
• +Free plan with 1,000 starter credits, one workspace and 5 GB of storage

Cons

• −Every plan is metered in credits, so cost tracks usage rather than headcount
• −The free allowance is one-time, not monthly, so ongoing use means a paid seat
• −Concurrency is capped per plan — 10 simultaneous executions on Free, 50 on Pro
• −SSO, access control and SOC2 paperwork sit behind the quoted Enterprise tier

Is Langflow cheaper than Sim?

Langflow is free to use; Sim starts at $25/seat/mo.

Does Langflow or Sim have a free tier?

Both: Langflow is free to use, and Sim has a free tier.

Which has a public API, Langflow or Sim?

Both ship a public API, so either can be built on; the fact table above shows the platforms each one runs on.