Reference
Developer references for HTTP status codes and TCP/UDP port numbers across API debugging, website troubleshooting, firewall configuration, and security audits.
5 tools
Reference
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HTTP Status Code Reference
Search HTTP status codes by number, phrase, category, source, and troubleshooting context for APIs, websites, proxies, CDNs, redirects, authentication errors, rate limits, and gateway failures.
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Port Reference
Search common TCP and UDP ports by number, protocol, service name, risk level, and exposure guidance for network configuration, firewall review, debugging, and security auditing.
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ASCII Table
A complete, searchable ASCII and Latin-1 reference with decimal, hex, octal, binary, glyph, HTML entity, escape sequence, and plain-language explanations for every control character.
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HTML Entity Reference
A searchable grid of every HTML named character reference, deduplicated to one card per character, with the glyph, code point, and one-click copy of the name, character, or numeric reference.
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Emoji Cheat Sheet
A searchable cheat sheet of 1,870 emoji with GitHub shortcodes, names, tags, and code points, plus one-click copy of the emoji, shortcode, Unicode, or HTML entity.
Open tool
About this category
Some answers you just need to look up. Which HTTP status code is right for a stale resource? What port does PostgreSQL listen on? Is 503 retryable? Which well-known ports should never be exposed to the public internet?
These references answer those questions in a few seconds, with the context you actually need around the bare number — common scenarios, recommended fixes, related codes or ports, and the source standard.
What you can do here
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HTTP status reference
Every HTTP status code with a one-line meaning, common scenarios, recommended fixes, retry semantics, and links to the spec.
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TCP/UDP port reference
Well-known and registered ports with the service they belong to, protocol notes, risk level, and exposure recommendations.
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Searchable and filterable
Filter by category (1xx–5xx) or protocol (TCP/UDP/SCTP), search by number, phrase, or service name to land on the right entry quickly.
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Pragmatic, opinionated notes
Each entry is more than a definition — it includes the kind of context you'd only get from someone who has shipped the thing.