Check Flux 3 Klein availability, inputs, parameters, file requirements, credit pricing, and request examples for Rivya Public API v1. Model ID: flux-3.

Available via APIText or URL ready; reference modes use Files APIImage

API model ID

flux-3

Inputs

text, file

Files API

Required for reference modes

Credit pricing

Credit rate: 1.6–6.5 per image The final cost is rounded up to whole credits.

Capability

Image

Billing

FIXED

Prompt limit

5000 characters

Request fields

Set model at the top level. Put model-specific controls and reference inputs in params, using the format documented for this model.

Key	Type	Required	Default	Description
model	string	Yes	flux-3	Set model to flux-3.
prompt	string	Yes	-	Maximum 5000 characters for this model.
params	object	No	-	The model-specific params object. Use the documented keys and reference-file format for this model.
client_request_id	string	No	-	Optional ID for tracing this request in your system. It does not replace Idempotency-Key.

Model parameters

Key	Type	Required	Default	Range	Options	Description
aspect_ratio	select	No	1:1	-	1:1, 4:3, 3:4, 3:2, 2:3, 16:9, 9:16, 21:9, 9:21	Aspect ratio
resolution	select	No	1K	-	1K, 2K, 4K	Resolution
output_format	select	No	png	-	png, jpeg, webp	Output format

Upload policy

Upload reference files through Files API first. Keep the original URLs, verified metadata, and tokens. Follow this model's request example: some models use params.referenceMediaItems, while others use different fields.

Reference rule

Reference image: Up to 10 JPEG, PNG, or WebP reference images, each no larger than 30 MB.

Max files

Accepted file kinds

image

Duration token

When duration verification is required, use duration_token from /api/v1/files as durationToken in the request. Keep any additional signed metadata this model requires.

kind	Max size	MIME types
image	29 MB	image/jpeg, image/png, image/webp

Minimal request

{
  "model": "flux-3",
  "prompt": "A product bottle on a light gray background, lit softly from the left.",
  "params": {
    "aspect_ratio": "1:1",
    "resolution": "1K",
    "output_format": "png"
  }
}

Reference-file request

{
  "model": "flux-3",
  "prompt": "A product bottle on a light gray background, lit softly from the left.",
  "params": {
    "aspect_ratio": "1:1",
    "resolution": "1K",
    "output_format": "png",
    "referenceMediaItems": [
      {
        "url": "https://cdn.example.com/reference-image.png",
        "kind": "image",
        "name": "reference-image.png",
        "mimeType": "image/png"
      }
    ]
  }
}

Example response

An accepted generation request returns a task ID. Poll the status endpoint until the task succeeds or fails. A status request failure does not mean generation failed.

{
  "id": "task_flux_3_example",
  "status": "queued",
  "model": "flux-3",
  "reserved_credits": 2,
  "final_credits": 0,
  "settlement_status": "RESERVED",
  "created_at": "2026-05-11T00:00:00.000Z",
  "updated_at": "2026-05-11T00:00:00.000Z",
  "result": null,
  "error": null
}

Common errors

validation_failed, insufficient_credits, idempotency_conflict, rate_limited, not_found

Some modes require Files API reference uploads.

Flux 3 Klein API reference