HTTP & Networking
What is an HTTP status code?
A three-digit number returned by an HTTP server that summarizes the result of a request, grouped into 1xx informational, 2xx success, 3xx redirect, 4xx client error, and 5xx server error.
Every HTTP response starts with a status line: HTTP/1.1 200 OK. The number is the machine-readable summary, the reason phrase is decoration. The first digit puts the response in a class (200 successful, 301 permanent redirect, 404 not found, 500 server error) which is enough for most error handling. The remaining two digits add specificity (404 vs 410 vs 451 are all "client problem, the resource is not where you think").
For crawlers, the status code is the primary signal for what to do next. 2xx means parse and continue. 3xx means follow the Location header (or do not, if the redirect chain is suspicious). 4xx means stop and either log or skip; 429 specifically means back off. 5xx means retry with exponential backoff.
A few status codes deserve special handling. 451 ("Unavailable For Legal Reasons") signals legal blocking, often geographic. 418 ("I'm a teapot") is a joke RFC; some sites return it as a polite "stop scraping me." And servers sometimes return a 200 with an HTML error page, which is why response-body sniffing complements status-code logic.
In the wild
- →A crawler treating 429 as "sleep 60 seconds, then retry once with backoff"
- →An SEO audit flagging every 404 in an internal link graph
- →A monitoring tool paging on-call when the 5xx rate exceeds 1% over 5 minutes
How Brand.dev uses http status code
Endpoints in the Brand.dev API where this concept comes up directly.
FAQ
What is the difference between 401 and 403?
401 means "you are not authenticated, send credentials." 403 means "you are authenticated but not authorized for this resource." 401 prompts a re-login flow; 403 prompts an access-request flow.
Is 301 better than 302 for SEO?
301 (permanent) passes link equity and tells search engines to update their index. 302 (temporary) does not. Use 301 for moves; use 302 only when you genuinely intend to revert.
What does 429 mean?
"Too Many Requests": you have exceeded a rate limit. Back off, ideally by reading the Retry-After header. Hammering after a 429 is the fastest way to escalate to a hard block.
Related terms
The application protocol the web is built on, a simple request/response format for asking a server for a resource.
HTTP encrypted with TLS, the same protocol, but every byte on the wire is authenticated and protected from eavesdroppers.
A server-side policy that caps how many requests a client can make in a given window, returning 429 Too Many Requests when the cap is exceeded.
A program that systematically follows links between web pages to discover and index content at scale.