API Documentation

Integrate image conversion into your applications with our REST API.

Authentication

All API requests require a Bearer token in the Authorization header.

Authorization: Bearer ic_your_token_here

Generate API tokens in your API Settings page. Tokens are shown once at creation — store them securely.

Endpoints

`GET` `/api/v1/convert`

Returns your current usage info, plan details, and supported formats.

Response

{
  "plan": "api_free",
  "label": "Free",
  "usage": {
    "used": 12,
    "limit": 50,
    "remaining": 38,
    "period": "day"
  },
  "maxFileSize": 10485760,
  "formats": ["png","jpg","webp","gif","bmp","tiff","avif","ico"]
}

`POST` `/api/v1/convert`

Convert an image file. Send as multipart/form-data.

Field	Type	Required	Description
`file`	File	Yes	The image file to convert
`format`	String	Yes	Target format (see supported formats below)
`quality`	Integer	No	Quality 1–100 (for formats that support it)

On success, returns the converted image binary with appropriate Content-Type and Content-Disposition headers.

Supported Formats

Format	Value	MIME Type	Quality Support
PNG	`png`	`image/png`	Yes
JPG	`jpg`	`image/jpeg`	Yes
WebP	`webp`	`image/webp`	Yes
GIF	`gif`	`image/gif`	No
BMP	`bmp`	`image/bmp`	No
TIFF	`tiff`	`image/tiff`	Yes
AVIF	`avif`	`image/avif`	Yes
ICO	`ico`	`image/x-icon`	No

Rate Limits

Rate limits reset daily. Upgrade your plan for higher limits.

Plan	Daily Limit	Max File Size	API Keys
Free	50	10 MB	1
Developer	500	25 MB	3
Business	5,000	50 MB	10

Response Headers

Successful conversion responses include rate limit headers:

Header	Description
`X-RateLimit-Limit`	Your daily conversion limit
`X-RateLimit-Remaining`	Conversions remaining today
`X-RateLimit-Reset`	ISO 8601 timestamp when the limit resets

Error Codes

Errors return JSON with an error field.

Status	Meaning	Common Causes
`400`	Bad Request	Missing file, invalid format, invalid quality value, malformed form data
`401`	Unauthorized	Missing or invalid API token
`413`	Payload Too Large	File exceeds your plan's size limit
`429`	Too Many Requests	Daily conversion limit reached
`500`	Internal Server Error	Conversion failed (corrupt file, unsupported input format)

{
  "error": "Daily API conversion limit reached",
  "limit": 50,
  "resetAt": "2025-01-02T00:00:00.000Z"
}

Code Examples

curl

curl -X POST https://format.select/api/v1/convert \
  -H "Authorization: Bearer ic_your_token_here" \
  -F "file=@photo.png" \
  -F "format=webp" \
  -F "quality=80" \
  -o photo.webp

JavaScript (fetch)

const form = new FormData();
form.append("file", fileInput.files[0]);
form.append("format", "webp");
form.append("quality", "80");

const res = await fetch("https://format.select/api/v1/convert", {
  method: "POST",
  headers: { "Authorization": "Bearer ic_your_token_here" },
  body: form,
});

if (!res.ok) {
  const err = await res.json();
  throw new Error(err.error);
}

const blob = await res.blob();
// Use the converted image blob

Python (requests)

import requests

url = "https://format.select/api/v1/convert"
headers = {"Authorization": "Bearer ic_your_token_here"}

with open("photo.png", "rb") as f:
    res = requests.post(url, headers=headers, files={
        "file": ("photo.png", f, "image/png"),
    }, data={
        "format": "webp",
        "quality": "80",
    })

res.raise_for_status()
with open("photo.webp", "wb") as out:
    out.write(res.content)

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