Image generation API

Live

Generate and edit images from a prompt or a reference picture.

From $0.0039 per image across 11 modelsCheapestFlux Schnell

from $0.0039/image

Input

PromptpromptWhat the image should show, or how to change the input image.

49 / 4,000

Aspect ratioaspect_ratio

Example

Example outputMade with this prompt a red paper boat on calm blue water, studio photo

Compare Image generation API models

Every model behind this endpoint, with live prices. Try one in the playground or open its page.

Flux SchnellBlack Forest Labs$0.0039 per image
Cheapest
Page
Z Image TurboAlibaba$0.00507 per image
$0.015 per image-66%
Page
GPT Image 1.5OpenAI$0.026 per image
$0.034 per image-23%medium
Page
Nano BananaGoogle$0.026 per image
$0.039 per image-33%Best value
Page
Seedream 4.0ByteDance$0.02925 per image
Below the maker's price
Page
Flux KontextBlack Forest Labs$0.0325 per image
$0.04 per image-18%
Page
GPT Image 2OpenAI$0.039 per image
$0.053 per image-26%medium
Page
Nano Banana 2Google$0.04589 per image
$0.067 per image-31%Best
Page
Nano Banana 2.1Google$0.0585 per image
$0.113 per image-48%
Page
Nano Banana ProGoogle$0.05928 per image
$0.134 per image-55%
Page
Flux DevBlack Forest Labs$0.065 per image
Page

Every model of this tool with its price
		Official			Lengths / sizes	Badges	Actions
Flux SchnellBlack Forest Labs	$0.0039 per image	No official price	—	—	—	Cheapest	Page
Z Image TurboAlibaba	$0.00507 per image	$0.015 per image	-66%	—	—		Page
GPT Image 1.5OpenAI	$0.026 per image	$0.034 per image	-23%	medium	—		Page
Nano BananaGoogle	$0.026 per image	$0.039 per image	-33%	—	—	Best value	Page
Seedream 4.0ByteDance	$0.02925 per image	Below the maker's price	—	—	—		Page
Flux KontextBlack Forest Labs	$0.0325 per image	$0.04 per image	-18%	—	—		Page
GPT Image 2OpenAI	$0.039 per image	$0.053 per image	-26%	medium	1K		Page
Nano Banana 2Google	$0.04589 per image	$0.067 per image	-31%	—	1K–4K	Best	Page
Nano Banana 2.1Google	$0.0585 per image	$0.113 per image	-48%	—	4K		Page
Nano Banana ProGoogle	$0.05928 per image	$0.134 per image	-55%	—	1K–4K		Page
Flux DevBlack Forest Labs	$0.065 per image	No official price	—	—	—		Page

Call Image generation API from your code

One endpoint for every model above. Change the model field to switch.

POSThttps://api.opennan.com/v1/images/generations

GET/v1/models?category=imageEvery model of this endpoint, with prices

Get an API key
Create a key in the console. It uses the same balance as the playground.
Create a key

Send your first request

The same request the playground sends. Set OPENNAN_KEY to your key.

curl https://api.opennan.com/v1/images/generations \
  -H "Authorization: Bearer $OPENNAN_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"flux-schnell","prompt":"A glass teapot on a sunlit windowsill, soft morning light, 35mm photo","aspect_ratio":"1:1"}'

# Then poll until "status" is "succeeded" or "failed":
curl https://api.opennan.com/v1/tasks/<task id> -H "Authorization: Bearer $OPENNAN_KEY"

Poll the task
The call answers right away with a task id. Ask for the task until it finishes:
GEThttps://api.opennan.com/v1/tasks/{id}
queued
Waiting for a worker
running
Being made
succeeded
Done: outputs[].url holds the files
failed
Failed: you are not charged

Parameters

Built from the live catalog: every value listed here is one the API accepts.

Parameters
Name	Type	Allowed values	Default	Effect on price
`model`requiredWhich model runs the call.	string	flux-dev · flux-kontext · flux-schnell · gpt-image-1-5 · gpt-image-2 · nano-banana · nano-banana-2 · nano-banana-2-1 · nano-banana-pro · seedream-4-0 · z-image-turbo	—	—
`prompt`optionalWhat the image shows.	string	—	—	—
`image`optionalAn image to edit or follow (https link).	URL	—	—	+$0.0195 per input image
`size`optionalOutput size.	string	1K · 2K · 4K	—	Bigger costs more
`quality`optionalQuality setting.	string	medium	—	—
`aspect_ratio`optionalFrame shape, for example 16:9 or 9:16.	string	1:1 · 2:3 · 3:2 · 3:4 · 4:3 · 4:5 · 5:4 · 9:16 · 16:9 · 21:9	—	—
`callback_url`optionalWe send the finished task to this URL.	URL	—	—	—

Errors and how to fix them

401Missing or wrong key
Send the header Authorization: Bearer with a key from the console.
402Balance too low
Add credit in Billing, then send the same call again.
400A value is not accepted
Read error.message: it names the field. Use a value from the parameter table.
429Too many requests
Wait a few seconds and try again, waiting longer after each 429.

Add Opennan to your AI app

One install gives your AI every Opennan tool: video, images, chat, voice, music, sound effects, 3D, captions and dubbing. Pick your app and follow the steps.

MCP serverhttps://api.opennan.com/v1/mcp

Works in the Codex CLI, the Codex app and the Codex IDE extension: they share ~/.codex/config.toml. If the app or IDE does not see OPENNAN_KEY, use the config.toml option with your key in it. Codex asks before each tool call: approve it to go on.

Get an API key
Create a key in the console. It starts with sk- and uses the same balance as the website.
Create a key

Save your key as OPENNAN_KEY

# macOS / Linux (zsh shown; bash: ~/.bashrc)
echo 'export OPENNAN_KEY="sk-..."' >> ~/.zshrc
source ~/.zshrc

# Windows (PowerShell), then open a new terminal
setx OPENNAN_KEY "sk-..."

3
Install the Opennan plugin: the server plus a skill that teaches your AI to pick models, confirm prices and wait for results
```
codex plugin marketplace add Opennan/opennan-ai-plugin
codex plugin add opennan@opennan
```

Or add only the server

codex mcp add opennan --url https://api.opennan.com/v1/mcp --bearer-token-env-var OPENNAN_KEY

Or add this to ~/.codex/config.toml

[mcp_servers.opennan]
url = "https://api.opennan.com/v1/mcp"
http_headers = { Authorization = "Bearer sk-..." }

4
Check that opennan is listed
```
codex mcp list
```
Restart Codex, then ask for anything
“Make a 5 second video of rain on a neon street, a song to go with it and a poster image.”

Replace sk-... with your own key and keep it private: anyone who has it can spend your balance. Your app can list the tools before you add a key; making anything needs one.

This tool from your AI

Once Opennan is added, your AI calls this tool with arguments like these.

Tool: generate_image
Example arguments: { "model": "flux-schnell", "prompt": "A glass teapot on a sunlit windowsill, soft morning light, 35mm photo" }

Image generation API: questions

Every model and price

How much does Image generation API cost?

From $0.0039 per image with Flux Schnell, the cheapest of 11 models here. You see the price before you run.

How do I call it from my code?

Send POST https://api.opennan.com/v1/images/generations with your API key. It answers with a task id: ask https://api.opennan.com/v1/tasks/{id} until the task succeeds or fails.

Can I switch models without changing my code?

Yes. Change the model field and keep the rest of the request, the same key and the same balance.

Can my AI agent use it?

Yes. Add the MCP server https://api.opennan.com/v1/mcp and call the generate_image tool, or point your agent at https://api.opennan.com/llms.txt.

What happens if a run fails?

A failed run is not charged. You pay only for results.