Sample

Configure request payload size limits in axum using DefaultBodyLimit to prevent automatic 413 Payload Too Large rejections on buffering extractors (Bytes, String, Json) at the default 2MB boundary, override limits per route or sub-router, and stream unbuffered raw requests without limits

sha256:adda974ec2d465cadc36ee9ef527ef98de16a608778e9bc8b0d096f4e2d504a3

PUBLISHED L3_CONTRACT_PASS MIT-0

Case

Goal: Configure request payload size limits in axum using DefaultBodyLimit to prevent automatic 413 Payload Too Large rejections on buffering extractors (Bytes, String, Json) at the default 2MB boundary, override limits per route or sub-router, and stream unbuffered raw requests without limits HOW
Packages: axum 0.8.9 tower 0.5.3 tokio 1.53.1 serde_json 1.0.151 http-body-util 0.1.5
Environment: rust
Created: 2026-08-16T08:07:16Z

assert buffering extractors (Bytes, String, Json) enforce an implicit 2MB (2,097,152 bytes) limit by default
assert a 2,097,152 byte payload succeeds with 200 OK on default routes
assert a 2,097,153 byte payload fails with 413 PAYLOAD TOO LARGE on default routes
assert malformed JSON exceeding 2MB returns 413 PAYLOAD TOO LARGE instead of 400 Bad Request or 422 Unprocessable Entity because body limit check precedes deserialization
assert the 413 rejection returns Content-Type text/plain; charset=utf-8 with body 'Failed to buffer the request body: length limit exceeded'
assert route-level DefaultBodyLimit::max overrides router-level limits to accept larger payloads
assert route-level DefaultBodyLimit::disable allows arbitrary payload sizes without 413 rejection
assert DefaultBodyLimit::max(0) accepts 0-byte bodies with 200 OK but rejects 1-byte bodies with 413
assert unbuffered raw Request streaming extractors bypass DefaultBodyLimit without requiring disable()
assert nested sub-routers enforce their own DefaultBodyLimit independently of parent router limits

rust 1 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · cargo@1 · 2026-08-16 · ed25519:d91480838ac982c9