FLUX 3 Klein API
The small, fast FLUX 3 image model, for cheap generation and edits at 1K and 2K.
FLUX 3 Klein is an image generation model from Black Forest Labs, available on OttoPort's OpenAI-compatible API as the model ID flux-3-klein at $0.011 / image as of 2026-11-14.
Provider
Black Forest Labs
Price
$0.011 / image
Model ID
flux-3-klein
Type
image generation model
Create with FLUX 3 Klein
image
FLUX 3 Klein API pricing
What OttoPort bills for FLUX 3 Klein, and what that works out to per unit. Rates are read from the same catalog the gateway meters against, and were current on 2026-11-14.
| Per image | $0.011 | at the model's base resolution |
|---|---|---|
| Images per $1 | 90 | |
| 100 images | $1.10 | |
| Up to 1024px longest side | $0.011 | 1× the base rate |
| Up to 2048px longest side | $0.0165 | 1.5× the base rate |
No subscription and no minimum — OttoPort bills prepaid credits against usage. See the full rate card.
Call FLUX 3 Klein in three lines
Send "model": "flux-3-klein" to POST https://ottoport.ai/api/v1/images/generations with an OttoPort key. No Black Forest Labs account, no waitlist, no separate SDK.
curl https://ottoport.ai/api/v1/images/generations \
-H "Authorization: Bearer $OTTOPORT_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "flux-3-klein",
"prompt": "a chrome torus on a black background, studio light",
"size": "1024x1024",
"n": 1
}'from openai import OpenAI
client = OpenAI(api_key="op-...", base_url="https://ottoport.ai/api/v1")
resp = client.images.generate(
model="flux-3-klein",
prompt="a chrome torus on a black background, studio light",
size="1024x1024",
n=1,
)
print(resp.data[0].url)import OpenAI from "openai";
const client = new OpenAI({ apiKey: "op-...", baseURL: "https://ottoport.ai/api/v1" });
const resp = await client.images.generate({
model: "flux-3-klein",
prompt: "a chrome torus on a black background, studio light",
size: "1024x1024",
n: 1,
});
console.log(resp.data[0].url);Before you start
- 1. Create a key at /api-keys.
- 2. Top up credits — the smallest pack is $25.
- 3. Paste the request. It returns on the same request.
Full reference at /docs, or drive it from an agent with the MCP server and CLI.
Request parameters
The body POST https://ottoport.ai/api/v1/images/generations accepts for FLUX 3 Klein.
| Field | Type | Required | Notes |
|---|---|---|---|
| model | string | Yes | Always flux-3-klein for FLUX 3 Klein. |
| prompt | string | Yes | What to generate. |
| size | string | No | e.g. 1024x1024. Resolutions above the base tier bill at a multiplier. |
| resolution | string | No | One of: 1k, 2k. Tiers above this model's base rate bill at a multiplier. |
| aspect_ratio | string | No | e.g. 16:9. Read only when size is absent. |
| n | integer | No | How many images to return. Each one bills separately. |
| image_url | string | No | A source image, for editing and reference-led generation. |
| image_urls | array | No | Several reference images at once, up to the model's limit — see its capabilities in /v1/models. Up to 3. |
FLUX 3 Klein direct vs through OttoPort
FLUX 3 Klein is the same model either way — what changes is how many accounts, keys, and integrations you carry to reach it.
| Black Forest Labs direct | Via OttoPort | |
|---|---|---|
| Accounts and keys | A Black Forest Labs account, plus one more for every other model you add | One OttoPort account and one key for the whole catalog |
| Request shape | Black Forest Labs's own SDK and response format | OpenAI-compatible — point baseURL at OttoPort and change the model string |
| Switching models | A new integration per provider | Replace flux-3-klein with any other model ID in the catalog |
| Billing | A separate invoice and contract per provider | Prepaid credits, no subscription, one usage ledger |
| Provider outages | Your call fails | Configured backup routes are tried in order on provider failure |
Put the hero subject first.
Describe composition and lighting.
Specify format and visual style.
FLUX 3 Klein API questions
Cost, keys, and model IDs for FLUX 3 Klein on OttoPort.
How much does the FLUX 3 Klein API cost?
On OttoPort, FLUX 3 Klein costs $0.011 / image as of 2026-11-14. For scale, images per $1: 90. Billing is prepaid usage with no subscription and no minimum, and the current rate is always published at ottoport.ai/pricing.
How do I get a FLUX 3 Klein API key?
You do not need a Black Forest Labs key. Create an OttoPort account, generate a key at ottoport.ai/api-keys, and send it as "Authorization: Bearer <key>" to POST https://ottoport.ai/api/v1/images/generations with "model": "flux-3-klein". The same key reaches every other model in the catalog.
What is the model ID for FLUX 3 Klein?
The OttoPort model ID for FLUX 3 Klein is flux-3-klein. Pass it as the model field on POST https://ottoport.ai/api/v1/images/generations, or list it programmatically from GET https://ottoport.ai/api/v1/models.
Can I call FLUX 3 Klein with the OpenAI SDK?
Yes. Set the OpenAI SDK's base URL to https://ottoport.ai/api/v1, use an OttoPort API key, and pass flux-3-klein as the model. Image generation follows the OpenAI images shape, so existing code works after changing two lines.
Do I need a Black Forest Labs account to use FLUX 3 Klein?
No. OttoPort connects to Black Forest Labs on your behalf, so one OttoPort account covers FLUX 3 Klein and every other model in the catalog — no per-provider contracts, keys, or invoices.
Other image generation models on the same API
Same endpoint, same key — swapping model is a one-string change from flux-3-klein.
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Browse the full catalog — every model with its provider and per-unit price.