Variant Also Negotiates

Server perspective

Use 506 for a transparent content negotiation misconfiguration where the selected variant is itself negotiable and causes a loop or invalid resolution path.

When to use

• •Return 506 only for transparent content negotiation configuration errors
• •Use it when the server cannot deliver a concrete representation because variant metadata is self-referential

How to respond

• •Fix the variant map, rewrite rules, or negotiated-resource metadata so each negotiable resource resolves to concrete variants
• •Log which variant selection path caused the loop so operators can repair the configuration quickly

Headers to consider

• •No status-specific header is required; standard negotiation headers may still appear, but the main fix is server-side configuration

Response body

• •A body is helpful; explain that content negotiation configuration is invalid and include a request or trace ID for support

Server-side pitfalls

• •Do not use 506 for ordinary Accept or Accept-Language mismatches; that is usually 406 Not Acceptable
• •Do not blame the client for a server-side negotiation loop

Examples