Technical SEO

404 error

Also known as: not found

A server response saying the requested resource was not found.

A practical example

A removed product no longer has a page at its old URL.

What should I know?

A polished error page should not pretend to be a successful 200 response.

Technical SEO in practice

Check crawler access, server responses, and content processing separately. Then assess indexing and search appearance. These stages are connected but distinct and need different diagnostic methods.

Related Semly features

See where this concept applies when working with Semly.

Google Search ConsoleConnect search data to Semly. Analyze queries and page performance when planning next steps.AI Agent LeonWork with Leon on recommendations, action plans, and brand content.

Related terms

Soft 404A page that looks like a missing resource while the server returns a success status, for example.HTTPA protocol for exchanging requests and responses between a client, such as a browser, and a server.301 redirectAn HTTP response pointing to a new URL and indicating a permanent move.

Documentation and further reading

Definition prepared by Semly. Standards and behavior are described by their creators:

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