4xx Client Error

HTTP 425 Too Early

The server is unwilling to risk processing a request that might be replayed. This is used with TLS Early Data (0-RTT) to protect against replay attacks.

Common Causes

  • Request sent using TLS 1.3 early data (0-RTT)
  • Server refusing replayed requests for safety
  • Non-idempotent request sent in early data

How to Fix

  1. 1Retry the request after the TLS handshake completes
  2. 2Only send idempotent requests in early data
  3. 3Disable TLS early data for sensitive operations

Example

HTTP 425 Too Early
POST /api/transfer HTTP/1.1
(sent via TLS 0-RTT early data)

→ 425 Too Early
→ "Retry after full handshake"

Related Client Error Codes

400

Bad Request

401

Unauthorized

402

Payment Required

403

Forbidden

404

Not Found

405

Method Not Allowed

406

Not Acceptable

407

Proxy Authentication Required

408

Request Timeout

409

Conflict

410

Gone

411

Length Required

412

Precondition Failed

413

Content Too Large

414

URI Too Long

415

Unsupported Media Type

416

Range Not Satisfiable

417

Expectation Failed

418

I'm a Teapot

421

Misdirected Request

422

Unprocessable Content

423

Locked

424

Failed Dependency

426

Upgrade Required

428

Precondition Required

429

Too Many Requests

431

Request Header Fields Too Large

451

Unavailable For Legal Reasons