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Models/Black Forest Labs/Flux 3 Klein
Black Forest Labsimage2 routes

Flux 3 Klein

Black Forest Labs's Flux 3 Klein: text to image and image editing, up to 4K.

flux-3-kleinGet API key

Pricing per image

SizePer image
768SQ$0.01lowest1 credit
1K$0.01lowest1 credit
1.5K$0.022 credits
2K$0.022 credits
4K$0.044 credits

Billed in credits per image (100 credits = $1, rounded up to a whole credit). Charged once, only for the route that succeeds. Failed attempts cost $0.00.

Request

# 1. Submit a generation and keep its id (a refusal prints {"error": {"message": ...}})
RESP=$(curl -s https://api.revana.si/v1/generations \
  -H "Authorization: Bearer $REVANA_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "flux-3-klein",
    "input": {
      "prompt": "A product photo of a ceramic coffee cup on a linen tablecloth, soft morning light",
      "resolution": "1K",
      "aspect_ratio": "16:9"
    }
  }')
echo "$RESP"
ID=$(echo "$RESP" | jq -r .id)

# 2. Poll it until status is "succeeded" or "failed" (a failed one has error.message)
curl -s https://api.revana.si/v1/generations/$ID \
  -H "Authorization: Bearer $REVANA_API_KEY"

# 3. Download the file once it has succeeded
curl -L https://api.revana.si/v1/generations/$ID/content \
  -H "Authorization: Bearer $REVANA_API_KEY" \
  -o out.png

Set REVANA_API_KEY to your key. Full reference in the quickstart.

Options

Tasks
Text to imageImage to image
Resolutions
768SQ1K1.5K2K4K
Aspect ratios
1:14:33:43:22:316:99:1621:99:21auto
Input images
Up to 10
Billing unit
per image
Model id
flux-3-klein

2 routes

Every request starts on the cheapest route. If it fails, the job moves to the next one automatically.

About the Flux 3 Klein API

How much does the Flux 3 Klein API cost?

Flux 3 Klein costs from $0.01 per image on Revana (768SQ: $0.01; 1K: $0.01; 1.5K: $0.02; 2K: $0.02; 4K: $0.04). You pay in prepaid credits, 100 credits to the dollar, with no subscription or monthly minimum. A generation that fails costs nothing.

How do I call Flux 3 Klein from code?

Send POST https://api.revana.si/v1/generations with {"model": "flux-3-klein", "input": {...}} and your Revana API key as a Bearer token, poll GET /v1/generations/{id} until it succeeds, then download GET /v1/generations/{id}/content. Every model on Revana takes the same request shape.

What happens if a Flux 3 Klein generation fails?

Revana has 2 routes for Flux 3 Klein. A job starts on the cheapest and moves to the next automatically if one fails. You are charged once, only for the route that delivers. A failed generation costs $0.00.

What can Flux 3 Klein do on Revana?

Flux 3 Klein supports text to image and image to image, resolutions 768SQ, 1K, 1.5K, 2K, 4K, aspect ratios 1:1, 4:3, 3:4, 3:2, 2:3, 16:9, 9:16, 21:9, 9:21, auto and up to 10 input images. A value it does not offer is refused with 422 before anything is charged.

Can my AI agent use Flux 3 Klein?

Yes. Connect the Revana MCP server (https://revana.si/api/mcp) to Claude, ChatGPT, Cursor or Codex, or have the agent call the REST API. The agent can list models, get a free quote and generate on your credits.

Compare with similar models

Also as markdown for agents. Every model and price: models.json.