# Credits and unlocking

One credit unlocks one image, once: every format of it, and every conversion of it after, are then free.

- `POST /v1/vectorize` always unlocks: it is the call that hands you the file.
- `POST /v1/conversions` spends nothing unless it says `"unlock": true`. Preview first, unlock what you keep with `POST /v1/conversions/{id}/unlock`.
- A conversion that fails or expires gives its credit back.
- A test key never spends a credit.
- Out of credits: `402 insufficient_credits`. A file of an image not unlocked: `402 unlock_required`.

Your balance: `GET /v1/credits`. Credits are bought on [pricing](https://vecsnap.com/pricing).

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This page: https://vecsnap.com/docs/credits-and-unlocking