Why RFC 7538 Introduced HTTP 308 Permanent Redirect
Defined in RFC 7538, HTTP 308 Permanent Redirect serves as the permanent counterpart to HTTP 307. Historically, web browsers receiving an HTTP 301 status code often converted POST requests into GET requests. In modern REST and GraphQL APIs, converting a POST or PUT into a GET causes payload loss and broken integrations.
HTTP 308 solves this by permanently transferring the resource while guaranteeing that the request method and body payload remain strictly preserved. Search engines like Google treat 308 identically to 301 for link equity transfer.
Server Configurations for Permanent 308 Redirects
Nginx Configuration (308)
# Permanent API upgrade preserving POST bodies
location /api/v1/ {
return 308 https://api.example.com/v2/$request_uri;
}Next.js (next.config.js) Redirect
// next.config.js permanent redirect (308)
module.exports = {
async redirects() {
return [
{
source: '/old-api/:slug*',
destination: '/new-api/:slug*',
permanent: true, // Emits 308 in Next.js
},
];
},
};Frequently Asked Questions About 308 Redirects
What is an HTTP 308 Permanent Redirect status code?
Defined in RFC 7538, an HTTP 308 Permanent Redirect status code signifies that the requested resource has been definitively assigned a new permanent URI. Unlike 301, the user agent MUST NOT alter the HTTP method: requests initiated with POST, PUT, or DELETE must be repeated at the target URL using the identical method and payload.
What is the key difference between HTTP 301 and HTTP 308?
While both 301 and 308 signal permanent relocation and pass link equity, legacy user agents frequently converted POST requests into GET requests upon receiving a 301. HTTP 308 eliminates this ambiguity by strictly guaranteeing that the original HTTP method and body are preserved across the redirect.
How does Google treat 308 redirects for SEO link equity?
Google treats HTTP 308 redirects identically to HTTP 301 redirects for SEO indexing and canonicalization. It passes 100% of PageRank link equity to the destination URL, making it completely safe for permanent modern web migrations.
When should modern APIs use 308 Permanent Redirect?
HTTP 308 is ideal for versioning RESTful APIs (e.g., redirecting /api/v1/users to /api/v2/users) and trailing slash canonicalization on microservices where clients submit structured JSON or multipart form bodies that must not be discarded.
Is HTTP 308 supported by all modern browsers and HTTP libraries?
Yes. HTTP 308 is supported across all modern browsers including Chrome, Safari, Edge, Firefox, and major HTTP client libraries like Axios, Fetch API, cURL, and Python Requests.