Question 1

What is burn0?

Accepted Answer

burn0 is an open-source npm package that tracks the cost of every API call in your stack — LLMs, SaaS APIs, infrastructure — from a single import.

Question 2

How does it work?

Accepted Answer

Add `import 'burn0'` as the first line of your entry file. It patches global fetch and wraps supported SDK clients to intercept API calls and extract cost metadata.

Question 3

Does it slow down my API calls?

Accepted Answer

No. Interception is synchronous but event processing is fully async. burn0 adds sub-millisecond overhead to your API calls.

Question 4

Is it really free?

Accepted Answer

Yes. burn0 is MIT licensed and free forever. No API key required for local mode. Cloud features (dashboard, team analytics) are coming as a paid tier.

Question 5

Does it send my data anywhere?

Accepted Answer

By default, no. In local mode, costs are logged to your terminal and stored in a local file. Cloud mode (opt-in) ships only metadata to the burn0 dashboard — never request/response bodies.

Question 6

Can I use it in production?

Accepted Answer

Yes. burn0 is designed for production use. It never throws, never adds latency, and gracefully degrades if anything fails internally.

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