Use the endpoint when your workflow already has text

Base64 is common in webhook payloads, AI image steps, document generators, and tools that cannot pass a binary file directly. FilePost accepts the encoded data, stores the decoded bytes, and returns a normal file URL.

JSON in

Send filename, content_type, and one of the supported base64 fields.

Bytes stored

FilePost decodes and stores the content without requiring your own bucket, access policy, or CDN.

Public URL out

Map url into the next workflow step. Keep file_id for later file management.

Copy the request

curl -X POST https://upload.filepost.dev/v1/upload/base64 \\
  -H "X-API-Key: fh_your_key" \\
  -H "Content-Type: application/json" \\
  -d '{
    "filename": "generated-report.pdf",
    "content_type": "application/pdf",
    "data_base64": "JVBERi0xLjQK...",
    "expires_in": "7d"
  }'

The response includes url, file_id, name, size, content_type, and expires_at. The aliases file_base64 and data are available when the upstream tool requires a different field name.

Keep the API key server-side

Use this endpoint from your backend, automation platform, or private webhook handler. Do not embed a production API key in a public browser bundle. For browser uploads, route the request through your own server or use the interactive first-upload path on the homepage.

See the full base64 API reference, the base64 upload guide, or the integration recipes.

Questions we actually get

Which base64 field should I send?

Use data_base64 by default. file_base64 and data are accepted aliases for tools that require a different field name.

Can I send a data URL?

Yes. FilePost accepts a plain base64 string or a complete data:...;base64,... value.

Can base64 uploads expire?

Yes. Add an expires_in value such as 24h or 7d. Without it, the URL has no automatic expiry.

Turn base64 data into a public URL.