Free test mode (mock runs)

You can build and run a complete flow before a single API key exists. A step that has no real key pool attached runs against a built-in mock provider: it returns placeholder output, immediately, for $0.

What it is genuinely good for

• Proving the wiring. Do the items arrive? Do the placeholders resolve? Does step two receive step one's output? Does a Decide card route items the way you expected?
• Rehearsing a chain end to end, including branches and loops, before it can cost anything.
• Chat-created flows. A flow created through FlowArray's own MCP server arrives as a draft with no pools attached — so it produces mock output until a person opens it and points it at real keys. Chatting can never spend your money by itself.

What it cannot tell you

Nothing about quality. The placeholder text is not what the model would say, and the placeholder image is not what it would render. Prompt wording, model choice, whether a vision reviewer can actually read your image — none of that is being tested. For that you need one real item.

Both halves of "free"

Mock runs are free because no provider call is made — not because FlowArray is absorbing a cost. The moment a step has a real pool, it is real money. The Builder says so next to Run: cards without a real key pool run in test mode.

Moving to real

1. An admin adds a key under API keys and puts it in a pool.
2. Pick that pool on the step.
3. Run one item first — a single real result tells you more about your prompt than fifty mock ones.
4. Then rehearse the full batch's inputs in the Data tab and run it.