File.io API

⭐ Beginner's Pick Cloud Storage & File Sharing / No Auth Required Beginner HTTPS
Free to Use Varies (check documentation)

Overview

File.io is an ephemeral file sharing API that returns a one-time download link after upload — once the file is downloaded, it is automatically deleted from the server. No account or API key is required for basic use, and file expiry can be controlled via a query parameter. This makes it ideal for securely passing temporary files between processes or services.

💡

Beginner Tip

Upload any file with a single curl command and receive back a JSON response with a shareable link. By default the link expires after one download, but you can set a duration like ?expires=1d or ?expires=1w for multi-download scenarios.

Available Data

File.io data via REST API
JSON-formatted response data
Freely accessible without authentication

Example Response

JSON Response
{
  "file_id": "f_abc123",
  "filename": "document.pdf",
  "size_bytes": 1048576,
  "mime_type": "application/pdf",
  "download_url": "https://example.com/files/f_abc123",
  "created_at": "2025-01-15T10:00:00Z"
}

Field Reference

success true if the file was uploaded and the link was generated successfully
link One-time download URL for the uploaded file, valid until downloaded or expired
key Short unique identifier for the file used to construct the download URL
expiry ISO 8601 datetime when the file and its link will be permanently deleted
size Size of the uploaded file in bytes

Implementation Example

const url = "https://www.file.io/";
const response = await fetch(url);
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

Common Errors & Troubleshooting

413 Payload Too Large File exceeds the 100MB limit for unauthenticated uploads
Register for a paid File.io plan to increase the size limit, or compress the file before uploading.
Link returns 404 after first access Default behavior deletes the file after a single download
Set the expires parameter to a duration string like 1w if the file needs to be downloaded more than once.
success: false in response body Missing or malformed multipart body in the upload request
Ensure the file field is named 'file' and the request uses multipart/form-data encoding, not raw body.

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 20/20
🔒 Security 15/15
🛠 Developer XP 15/20
✓ Reliability 7/15
Response Time 74ms

Fully tested on Apr 5, 2026

Technical Specifications

Auth No Auth
HTTPS REQUIRED
CORS UNKNOWN
Difficulty Beginner
Verified: 2026-04-04

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