Billing

Estimate

POST /estimate takes the same body as POST /jobs and returns what submitting it now would hold. It charges nothing and creates no job.

curl https://api.blon.ai/v1/estimate \
  -H "Authorization: Bearer $BLON_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"gpt-image-2","input":{"prompt":"A ceramic teapot on a linen table, soft morning light"}}'

{
  "model": "gpt-image-2",
  "cost": {
    "currency": "CREDITS",
    "amount": "8"
  },
  "kind": "exact",
  "reason": null
}

kind is exact when the price is known from the inputs, or upper_bound when part of it depends on the output; reason then explains the bound. A {url} input is imported first, because the price can depend on its duration.

Holds and charges

Submit. Blon holds the estimate from your balance. A balance that cannot cover it fails with 402 insufficient_credits.
Finish. A completed job is charged from its measured usage (the job’s usage). What is left of the hold is released.
Fail or cancel. The hold is released and charged is "0".

The job’s cost shows this:

Field	Meaning
`currency`	`USD` for a `blon_api_` key, `CREDITS` otherwise
`estimated`	The estimate held at submission. It does not change
`charged`	What was charged; `null` until the job is terminal
`refunded`	Money returned after a charge

A released hold is not a refund and does not appear in refunded. A job is always charged at the price in effect when it was submitted.

Balance

curl https://api.blon.ai/v1/balance \
  -H "Authorization: Bearer $BLON_API_KEY"

{
  "currency": "USD",
  "available": "18.425",
  "held": "0.0042",
  "usage_this_month": "1.5708",
  "spend_limit": {
    "amount": "50.00",
    "spent": "1.5708",
    "window": "month",
    "resets_at": "2026-11-01T00:00:00.000Z"
  }
}

Field	Meaning
`available`	What you can spend now
`held`	Held for jobs that are not finished
`usage_this_month`	Spent this calendar month
`spend_limit`	Only when the key has a spend limit: `amount`, `spent`, `window` (`day`, `week`, `month` or `lifetime`) and `resets_at`

Over the spend limit, submissions fail with 403 api_key_spend_limit_exceeded.

Usage

curl "https://api.blon.ai/v1/usage?timeframe=day" \
  -H "Authorization: Bearer $BLON_API_KEY"

{
  "currency": "USD",
  "timeframe": "day",
  "start": "2026-10-24T00:00:00.000Z",
  "end": "2026-10-31T00:00:00.000Z",
  "data": [
    {
      "bucket_start": "2026-10-30T00:00:00Z",
      "model": "gpt-image-2",
      "api_key_id": "key_7d2f9a",
      "jobs": 12,
      "units": {
        "output_images": 12
      },
      "cost": "0.48"
    }
  ]
}

Parameter	Meaning
`timeframe`	`hour`, `day`, `week` or `month`. Default `day`
`start`	RFC 3339. Default 7 days before `end`
`end`	RFC 3339. Default now. At most 31 days after `start`

Only settled jobs are counted, bucketed by settlement time. cost is charged net of refunds. Usage is a report, not an invoice.

Get started

Concepts

How-to

Models

Help

Estimate

Holds and charges

Balance

Usage

​Estimate

​Holds and charges

​Balance

​Usage

Estimate

Holds and charges

Balance

Usage