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Pricing and billing

How a price is computed, how to read it before you send, and how the prepaid balance holds and charges each task.

Every price is a flat USD number you can total before a task starts. An image is priced per output, a video per second, and the analysis tools per call. Creating a task holds the estimate on your balance. Completing it charges only what succeeded and releases the rest.

There is no subscription and no minimum spend. You prepay credits in the wallet. The minimum top-up is $5, with no Mynth fee on top. An idle account is never billed.

Do not hardcode prices from these docs. They change when providers change theirs. Read them from GET https://api.mynth.io/models or /models.json, or price a real request with an estimate call.

Where prices come from#

Providers bill by megapixel, by token, or by GPU time. Mynth publishes one number per model, usually the provider's own price. Where it is higher, the difference covers routing, retries, and delivery, and it is already included.

The catalog carries prices as decimal strings in USD:

FieldMeaning
pricing.perImage.baseOne image at the model's normal size
pricing.perImage["4k"]One image at a _4k size. Absent when the model has none
pricing.perInputEach input image, charged per output. Absent means $0
pricing.perSecondVideo, keyed by resolution tier
pricing.audioVideo audio per second, when billed separately

The catalog is at mynth.io/models, the pricing table, GET https://api.mynth.io/models, /models.json, and npx @mynthio/cli models list. None of them need an API key.

Image price#

per image  = perImage[scale] + perInput × number of inputs
task       = per image × successful images

scale is 4k for a _4k size and base otherwise. Nothing else changes the price: not prompt length, pixel count within a scale, output format, webhooks, destinations, which provider ran the job, or how many retries it took.

For example, with perImage.base at $0.03 and perInput at $0.03, a request with count: 2 and two reference images holds $0.18 and charges $0.09 per image that succeeds.

A _4k size on a model without a 4k price fails the task with CAPABILITY_NOT_SUPPORTED, and a failed task costs nothing.

With model: "auto", the hold is a flat $0.20 per image because the model is not chosen yet. On completion Mynth charges the published price of the model in result.model and releases the rest. See the model field.

Video price#

video = (perSecond[resolution] + audio.perSecond) × duration

An omitted resolution, duration, or audio uses the model's default, and the estimate includes it. audio.perSecond applies only when the catalog lists it. The video models available today include audio in perSecond.

Tool prices#

RequestPrice
POST /image/rate$0.0002
rating on POST /image/generate$0
POST /image/alt$0.0004
POST /image/review with effort: "low"$0.01
POST /image/review with effort: "high"$0.30
POST /image/remove-background$0.02
magic_prompt on POST /image/generate$0
POST /image/upload$0

Magic Prompt is included in the generation estimate, so if it gets a price later, the estimate will show it.

Before you send#

POST /image/generate/estimate and POST /video/generate/estimate take the same body as generate. They validate it and return the price without creating a task or holding anything. Estimate cost has the request and response.

Balance#

available = balance − reserved

balance     credits on the account
reserved    held by tasks that are still pending
available   what the next task can hold

GET /balance returns all three as decimal strings. It needs a key with the manage scope. npx @mynthio/cli balance prints them.

{
  "data": { "balance": "12.50", "reserved": "0.18", "available": "12.32", "currency": "usd" }
}

Holds and charges#

create task ── hold estimatedCost against available
  │
  ├─ completed ── charge each successful output, release the rest of the hold
  └─ failed ───── release the whole hold, charge $0
  • The create response returns the hold as estimatedCost.
  • If available is below the hold, the create fails with 422 INSUFFICIENT_BALANCE and nothing is queued.
  • If the key's spending limit would be passed, it fails with 429 SPENDING_LIMIT_EXCEEDED.
  • Only successful outputs are charged. If three of four images fail, you pay for one.
  • The amount charged is cost on the finished task. It is null while the task is pending and when it failed.

A task still pending 24 hours after its last update is failed with TASK_EXPIRED by a sweep that runs daily at 02:00 UTC, and its hold is released. The sweep looks at tasks last updated within the past 7 days. If reserved stays high after that, email mynth@mynth.io.

Refunds#

Credits are for spending on Mynth and are not paid back as cash. The terms cover refunds when a charge was our fault. The wallet lists each top-up and each charge with what it paid for.

Next steps#