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Credits are the currency Examino uses for AI-powered grading. Every time you launch a correction, Examino reserves credits before processing begins and confirms the charge once each copy is graded. Understanding how credits are counted — and how they flow through your team hierarchy — helps you plan capacity and avoid failed launches.

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How credits are calculated

Examino charges 1 credit per started 20-page block per copy. Fractional blocks round up, so a 12-page copy costs 1 credit and a 45-page copy costs 3. Page count is determined from the uploaded file at the moment correction is launched.

1–20 pages

1 credit per copy

21–40 pages

2 credits per copy

41–60 pages

3 credits per copy
Re-running correction on a copy that already has status: "success" is free. Examino only charges credits for copies that are newly processed in each correction launch.

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Credit balance inheritance

Teams in Examino are organised in a hierarchy. If a team has no direct credit balance, it automatically draws from its nearest ancestor that holds a balance. This lets institutions allocate credits at the faculty or institution level and let departments consume from that shared pool without manual top-ups at every node.

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Check your balance

Use GET /api/v1/credits with the credits:read scope to fetch the available balance for any team you administer.
Check credit balance
Response
Check your balance before every correction launch, especially for large exams. The correction endpoint returns 422 INSUFFICIENT_CREDITS if you don’t have enough — verifying upfront avoids a failed launch and makes your pipeline easier to debug.

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Transfer credits between teams

If you need to redistribute credits across your hierarchy, use POST /api/v1/credits/transfers. This endpoint requires the credits:write scope.
Transfer credits
Response
The response includes the updated balances for both teams so you can confirm the transfer in a single call.
Transfers and correction charges are attributed to the exact API key that initiated them, never to the user who created that key. Administrators can inspect the key name and public prefix in the credit ledger; regular organization members only see that the operation came from the API.

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Transfer rules

Not all transfers are permitted. The three rules below define when a transfer succeeds and what error you receive when it doesn’t.
You can only transfer credits between a team and one of its direct or indirect descendants — in either direction. Sibling teams (teams that share a common parent but are not in an ancestor–descendant relationship with each other) cannot transfer credits directly.Attempting a sibling-to-sibling transfer returns:
The source and destination teams must both be inside the API key’s team subtree. Authorization is based on the key itself — not on the user who originally created it. If either team is outside the key scope, the API returns 404 not_found without revealing whether that team exists.
Transfers are atomic — Examino never partially debits the source team. If fromTeamId does not hold enough credits to cover amount, the entire transfer is rejected:
Check the source balance with GET /api/v1/credits before submitting large transfers to avoid this error.

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Correction launch and credit checks

When you call POST /exams/{examId}/corrections, Examino validates your credit balance before reserving anything. If the team (including any ancestor balance) cannot cover the cost of all pending copies, the launch is rejected with a 422 INSUFFICIENT_CREDITS error and no credits are consumed.
A rejected launch does not create a partial correction. You must add credits and resubmit — use a new idempotencyKey if you change the correction scope, or reuse the same key if the request is identical.