Font conversion API.

Welcome to the Font Converter API

A powerful RESTful API for converting font files between various formats including TTF, OTF, WOFF, WOFF2, EOT, and SVG. Check the format capabilities for supported combinations. UFO directory uploads are not currently supported.

Quick Start

1. Check Service Status

Check availability and the current upload limits:

2. Submit a Conversion Job

Upload font files and specify target formats:

curl -X POST https://onlinefontconverter.com/api/convert \
  -F "files=@myfont.ttf" \
  -F "targetFormats=WOFF,WOFF2" \
  -F "output=zip"

3. Check Job Status

Monitor the conversion progress using the job ID:

4. Download Results

Once complete, download the converted fonts:

Download fonts as they finish

You can download each successful conversion while the rest of the batch is still running. Poll the conversions endpoint and use each item's downloadUrl when it becomes available. Each result also includes its filename, size and SHA-256 checksum.

When changing a batch, upload the complete current selection and include reuseJobIds: a comma-separated list of up to 64 previous job IDs, newest first. Matching successful conversions are reused; only missing combinations are converted. The server checks file contents, source format and target format. Expired or missing results are converted again. The response status includes reusedConversions, and each conversion includes reused. Treat job IDs as private download credentials.

For the complete batch, keep using the job's ZIP or TAR download when its status is COMPLETE. Files stay available for one hour after completion.

Keep job URLs private: anyone with a job link can access its files. The website's Start over button clears your local workspace; existing API jobs and download links expire as usual.

Key Features

API Endpoints

Limits & Retention

Code Examples

JavaScript (Fetch API)

// Submit conversion job
const formData = new FormData();
formData.append('files', fileInput.files[0]);
formData.append('targetFormats', 'WOFF,WOFF2');
formData.append('output', 'zip');

const response = await fetch('/api/convert', {
  method: 'POST',
  body: formData
});

if (!response.ok) throw new Error('Conversion request failed');
const { jobId, eventsUrl } = await response.json();

// Monitor progress with SSE
const eventSource = new EventSource(eventsUrl);
eventSource.onmessage = (event) => {
  const progress = JSON.parse(event.data);
  console.log(`Progress: ${progress.progress.processingPct}%`);
  if (['COMPLETE', 'FAILED', 'EXPIRED'].includes(progress.status)) {
    eventSource.close();
  }
};

Python

import time
from urllib.parse import urljoin
import requests

# Submit conversion job
files = {'files': open('myfont.ttf', 'rb')}
data = {'targetFormats': 'WOFF,WOFF2', 'output': 'zip'}

response = requests.post('https://onlinefontconverter.com/api/convert',
                        files=files, data=data)
response.raise_for_status()
job = response.json()

# Poll for completion
while True:
    status = requests.get(f"https://onlinefontconverter.com/api/jobs/{job['jobId']}")
    status.raise_for_status()
    job_data = status.json()
    if job_data['status'] in ('FAILED', 'EXPIRED'):
        raise RuntimeError(job_data.get('error') or job_data['status'])
    if job_data['status'] == 'COMPLETE':
        break
    time.sleep(1)

# Download results
with open('converted.zip', 'wb') as f:
    result = requests.get(urljoin('https://onlinefontconverter.com', job_data['downloadUrl']))
    result.raise_for_status()
    f.write(result.content)

Additional Resources

• Interactive API Documentation (Swagger UI) ↗
• OpenAPI 3.0 Specification (JSON) ↗