Docs — swapfile.io

How swapfile.io works

The converter and metadata cleaner run entirely in your browser using the File API and canvas. Your file is read into memory on your device, processed there and downloaded from there. For formats a browser cannot decode (like HEIC outside Safari), a server-side pipeline is coming; those jobs will be deleted from storage within one hour.

Data flow

local toolsfile → your browser → your downloads folder

server tools (soon)file → presigned upload → worker → download link → auto-delete ≤ 1h

API

Convert files from your own code with a REST API. It runs the same server pipeline as the site: you register an upload, send the bytes, start a conversion job, then download the result — all authenticated with an API key.

Create an API key in your account

Authentication

Every request carries your key in the Authorization header (Bearer), or an X-API-Key header. Treat it like a password — it spends your account's conversion quota.

https://api.swapfile.ioLive

curl https://api.swapfile.io/v1/jobs/{id} \
    -H "Authorization: Bearer sf_live_..."

Converting a file

heic → jpeg

# 1 · register the upload → presigned URL
curl -X POST https://api.swapfile.io/v1/uploads \
    -H "Authorization: Bearer sf_live_..." \
    -H "Content-Type: application/json" \
    -d '{"size": 48213}'
→ {"file_id":"9f2c…","upload_url":"https://…"}

# 2 · send the raw bytes to that URL
curl -X PUT --upload-file photo.heic "$UPLOAD_URL"

# 3 · start the conversion
curl -X POST https://api.swapfile.io/v1/jobs \
    -H "Authorization: Bearer sf_live_..." \
    -H "Content-Type: application/json" \
    -d '{"file_id":"9f2c…","operation":"convert:jpeg","params":{"quality":"82"}}'
→ 202 {"id":"7ab1…","status":"queued"}

# 4 · poll until done, then download
curl https://api.swapfile.io/v1/jobs/7ab1… \
    -H "Authorization: Bearer sf_live_..."
→ {"status":"done","download_url":"https://…"}

Endpoints

POST/v1/uploadsRegister an upload; returns a presigned PUT URL.

PUT{upload_url}Send the raw file bytes (max 100 MB).

POST/v1/jobsStart a conversion job for an uploaded file.

GET/v1/jobs/{id}Job status; includes download_url once done.

DELETE/v1/jobs/{id}Delete the file and job immediately.

Operations

Pass one of these as the operation. Accepted inputs include JPEG, PNG, WebP, GIF, BMP, HEIC, AVIF and TIFF.

convert:jpeg→ JPEG · params: quality (1–100)

convert:png→ PNG (lossless)

convert:webp→ WebP · params: quality (1–100)

Limits

100 MB max upload
30 conversions / day (free)
60 requests / minute per key
Files auto-deleted within 1 hour

Errors

Failures return RFC 9457 problem+json with a stable code field — for example unauthorized, unsupported_format, file_too_large, quota_exceeded or rate_limited.

Verify it yourself

Open your browser's developer tools, watch the network tab and convert a file. You will see no request carrying your file.