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What is free vs billable

Free: reads, exports, and prompt helpers

Get and list diagrams, versions, warnings, gallery search, usage, meta, me, every export, and the enhance / clarify prompt helpers.

Billable: writes

Generate, edit, fix, re-layout, and fork each cost credits.
Test mode is not free. dgz_test_ keys bill the same credits as a live key, at lower rate limits. See Authentication.

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Free credits

A new account receives 10 credits once, at signup. There is no monthly free allowance. When those are spent you can top up, at 5 dollars for 25 credits, or move to Pro or Power. The balance is one number per account, shared across the web app, the API, the MCP server, and the SDKs. Live and test keys draw from the same balance.

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Connecting is free

Running login costs nothing. It creates a scoped API key on your account, and creating a key has never consumed credits. You pay to create a diagram, never to connect a client and never to get a diagram out.

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Seeing what you spent

Every billable response includes a usage block:
For a durable, itemized record, including which surface (api, sdk, or mcp) ran each task, use GET /usage/history.

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Managing plan and credits

Plans, credit balances, and top-ups are managed in your account under Billing. If you run out of credits, a billable call returns a 402 (see Errors) while reads and exports keep working.
Per-action credit costs and plan limits are shown in the app and may evolve. Treat the usage block as the source of truth for what a specific call charged.