OpenAI Compat API

The OpenAI Compat API is a drop-in replacement for OpenAI’s official Images API. Fully compatible with the official openai SDK (Python & Node.js) and the raw OpenAI REST interface — just change the base_url.

No code changes needed — if you already use OpenAI’s images.generate / images.edit, simply override base_url to https://api.mountsea.ai/openai/v1 with your Mountsea API key.

Why Use Compat API?

Official SDK Support

Works with OpenAI’s official openai Python and Node.js SDKs

Same API Shape

Same request/response format as https://api.openai.com/v1/images/*

Synchronous

Returns the generated image directly — no polling needed

Unified Billing

Single API key, unified usage tracking through Mountsea

Configuration

Base URL

https://api.mountsea.ai/openai/v1

Authentication

Use your Mountsea API key:

HTTP header: Authorization: Bearer your-api-key
Or set via the SDK’s api_key / apiKey parameter

Supported Endpoints

Endpoint	Method	Description
`/openai/v1/images/generations`	POST	Text-to-image (JSON). Extra: JSON `image` sync-routes to edit
`/openai/v1/images/edits`	POST	Edit (`multipart/form-data`) — identical to OpenAI
`/openai/v1/models`	GET	Static GPT Image model list

Supported Models

Model	Description
`gpt-image-2`	Default. Quality `low` / `medium` / `high` / `auto`
`gpt-image-2.5-flare`	Official 2.5 — extra `xhigh` / `max`
`gpt-image-2.5-sunburst`	Official 2.5 — extra `xhigh` / `max`

Using the Official `openai` SDK

Installation

pip install openai

npm install openai

pnpm add openai

Python

from openai import OpenAI
import base64

client = OpenAI(
    api_key="your-mountsea-api-key",
    base_url="https://api.mountsea.ai/openai/v1",
)

response = client.images.generate(
    model="gpt-image-2",
    prompt="A photorealistic cat wearing a space helmet, floating in orbit",
    size="1024x1024",
    quality="high",
    n=1,
)

# default response_format is url (our S3)
image_url = response.data[0].url
# or pass response_format="b64_json" and use response.data[0].b64_json

from openai import OpenAI
import base64

client = OpenAI(
    api_key="your-mountsea-api-key",
    base_url="https://api.mountsea.ai/openai/v1",
)

with open("source.png", "rb") as img:
    response = client.images.edit(
        model="gpt-image-2",
        image=img,
        prompt="Add a dramatic sunset sky with orange and purple clouds",
        size="1024x1024",
        input_fidelity="high",
    )

image_url = response.data[0].url

from openai import OpenAI
import base64

client = OpenAI(
    api_key="your-mountsea-api-key",
    base_url="https://api.mountsea.ai/openai/v1",
)

with open("source.png", "rb") as img, open("mask.png", "rb") as mask:
    response = client.images.edit(
        model="gpt-image-2",
        image=img,
        mask=mask,
        prompt="Replace the masked area with a sunset beach",
        size="1024x1024",
    )

image_url = response.data[0].url

Node.js / TypeScript

import OpenAI from 'openai';
import fs from 'fs';

const client = new OpenAI({
  apiKey: 'your-mountsea-api-key',
  baseURL: 'https://api.mountsea.ai/openai/v1',
});

const response = await client.images.generate({
  model: 'gpt-image-2',
  prompt: 'A photorealistic cat wearing a space helmet, floating in orbit',
  size: '1024x1024',
  quality: 'high',
  n: 1,
});

const imageUrl = response.data[0].url;

import OpenAI, { toFile } from 'openai';
import fs from 'fs';

const client = new OpenAI({
  apiKey: 'your-mountsea-api-key',
  baseURL: 'https://api.mountsea.ai/openai/v1',
});

const response = await client.images.edit({
  model: 'gpt-image-2',
  image: await toFile(fs.createReadStream('source.png'), 'source.png'),
  prompt: 'Add a dramatic sunset sky with orange and purple clouds',
  size: '1024x1024',
  input_fidelity: 'high',
});

const imageUrl = response.data[0].url;

import OpenAI, { toFile } from 'openai';
import fs from 'fs';

const client = new OpenAI({
  apiKey: 'your-mountsea-api-key',
  baseURL: 'https://api.mountsea.ai/openai/v1',
});

const response = await client.images.edit({
  model: 'gpt-image-2',
  image: await toFile(fs.createReadStream('source.png'), 'source.png'),
  mask: await toFile(fs.createReadStream('mask.png'), 'mask.png'),
  prompt: 'Replace the masked area with a sunset beach',
  size: '1024x1024',
});

const imageUrl = response.data[0].url;

Using the REST API Directly

If you don’t want to use the SDK, you can call the endpoints directly.

Text-to-Image (JSON)

curl -X POST "https://api.mountsea.ai/openai/v1/images/generations" \
  -H "Authorization: Bearer your-api-key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-image-2",
    "prompt": "A photorealistic cat wearing a space helmet, floating in orbit",
    "size": "1024x1024",
    "quality": "high",
    "n": 1
  }'

Image Edit (multipart/form-data)

curl -X POST "https://api.mountsea.ai/openai/v1/images/edits" \
  -H "Authorization: Bearer your-api-key" \
  -F "model=gpt-image-2" \
  -F "image=@source.png" \
  -F "prompt=Add a dramatic sunset sky" \
  -F "size=1024x1024" \
  -F "input_fidelity=high"

Inpainting (multipart/form-data)

curl -X POST "https://api.mountsea.ai/openai/v1/images/edits" \
  -H "Authorization: Bearer your-api-key" \
  -F "model=gpt-image-2" \
  -F "image=@source.png" \
  -F "mask=@mask.png" \
  -F "prompt=Replace the masked area with a sunset beach" \
  -F "size=1024x1024"

Request Parameters

`images/generations` (JSON)

Field	Type	Description
`prompt`	string (required)	Prompt for image generation
`model`	string	Default `gpt-image-2`; also `gpt-image-2.5-flare` / `gpt-image-2.5-sunburst`
`size`	string	Presets or custom `WxH` (same constraints as async). Default `1024x1024`
`n`	number	Currently only 1
`quality`	enum	`auto` / `low` / `medium` / `high` / `standard`; 2.5 also `xhigh` / `max`
`background`	enum	`transparent`, `opaque`, `auto`
`output_format`	enum	`png`, `jpeg`, `webp`
`output_compression`	number	0-100 for JPEG/WebP
`moderation`	enum	`auto`, `low`
`response_format`	enum	`url` (default, our S3) or `b64_json` — strictly one field
`user`	string	End-user identifier for abuse monitoring
`image`	string / string[]	Private. URL / data URL / base64 — presence sync-routes to edit
`mask`	string	Private. Only with `image`

`images/edits` (multipart/form-data)

All fields above plus:

Field	Type	Description
`image`	file (required)	Source image
`mask`	file	Optional mask; transparent areas will be repainted
`input_fidelity`	`high` / `low`	How closely the output follows the input image

Response Format

Identical to OpenAI’s official response:

{
  "created": 1712345678,
  "data": [
    {
      "url": "https://cdn.example.com/out.png",
      "revised_prompt": "<model's improved prompt>"
    }
  ],
  "background": "opaque",
  "output_format": "png",
  "quality": "high",
  "size": "1024x1024",
  "usage": {
    "input_tokens": 45,
    "input_tokens_details": { "image_tokens": 0, "text_tokens": 45 },
    "output_tokens": 3200,
    "total_tokens": 3245
  }
}

This service honors response_format for every channel, including gpt-image models whose upstream returns b64. Default is url (our S3). You never get both url and b64_json.

Notes & Limitations

Currently n only supports 1. Multi-image generation per request is not yet supported.

All standard OpenAI parameters are supported; unknown parameters are ignored gracefully.
JSON image on /images/generations is a Mountsea extension (official SDK will not send it).
Both openai SDK and raw REST calls work identically.

Explore the API Documentation

images.generate (Compat) — generate (JSON edit diversion)
images.edit (Compat) — multipart edit
models.list (Compat) — supported models

​OpenAI Compat API

​Why Use Compat API?

Official SDK Support

Same API Shape

Synchronous

Unified Billing

​Configuration

​Base URL

​Authentication

​Supported Endpoints

​Supported Models

​Using the Official openai SDK

​Installation

​Python

​Node.js / TypeScript

​Using the REST API Directly

​Text-to-Image (JSON)

​Image Edit (multipart/form-data)

​Inpainting (multipart/form-data)

​Request Parameters

​images/generations (JSON)

​images/edits (multipart/form-data)

​Response Format

​Notes & Limitations

​Explore the API Documentation

OpenAI Compat API

Why Use Compat API?

Configuration

Base URL

Authentication

Supported Endpoints

Supported Models

Using the Official `openai` SDK

Installation

Python

Node.js / TypeScript

Using the REST API Directly

Text-to-Image (JSON)

Image Edit (multipart/form-data)

Inpainting (multipart/form-data)

Request Parameters

`images/generations` (JSON)

`images/edits` (multipart/form-data)

Response Format

Notes & Limitations

Explore the API Documentation