Dev Reference

about this tool

Four tables, one search box

Pick a table and type. A number matches as a prefix, so 40 narrows the status codes to the 400s and 44 the ports to 443 and 445; 4xx matches a whole class; words match anywhere in the name and description, and every word has to match, so not found gives 404 alone. Each row has a copy button for the value you would paste.

HTTP status codes

The list is IANA's registry as consolidated by RFC 9110, with the section reference for each code so you can read the definition rather than a paraphrase. RFC 9110 renamed two codes in 2022 — 413 is Content Too Large, 422 is Unprocessable Content — and the table uses those names. A handful of codes you will meet in logs but that IANA has never assigned are included and marked unofficial: 418 (an April Fools' RFC), nginx's 444 and 499, and Cloudflare's 520 to 527. Each names the software that emits it instead of an RFC.

MIME types

The MIME table is the whole mime-db registry, about 2,500 types, of which roughly a thousand have file extensions. It is fetched the first time the tab is opened, not with the page. Searching by extension puts the exact match first; searching by word matches the type name. The list is capped at two hundred rows, and the heading says how many matched in total, because a matches most of the registry. With no query, only types that have extensions are listed, since those are the ones people look up.

Some mappings surprise people, which is the point of having the table: .ts is video/mp2t (MPEG transport stream), not TypeScript; .js is text/javascript by IANA and application/javascript by older Apache configurations, and both are listed with their source.

Keycodes

Click the box and press a key to see what a keydown event carries: key (what the key produces on your layout), code (which physical key it is), the legacy keyCode and which, the location (left, right or numpad), active modifiers, and whether the event is a repeat. Inside the box, Tab and Space are captured rather than acted on. Keys pressed while typing in the search field are not captured.

The table below lists the codes with their keyCode values as most browsers report them. keyCode is deprecated and layout-dependent, and Firefox disagrees on some punctuation; the notes say where. key values in the table are for a US layout, unshifted.

Ports

Not the full IANA registry, which runs to thousands of mostly-historical entries, but the ports a developer meets: the classic services, databases, message queues, and the default ports of common development servers, which are conventions rather than registrations. The range column gives IANA's classification: 0–1023 well-known, 1024–49151 registered, 49152–65535 dynamic.

questions

Where do the status codes come from?

The IANA HTTP Status Code Registry, which RFC 9110 (2022) consolidates. A few codes you will meet in practice but that IANA has not assigned — 418, nginx’s 444 and 499, Cloudflare’s 520 to 527 — are included and marked unofficial, with the software that emits them named instead of an RFC.

Why is 413 called Content Too Large and 422 Unprocessable Content?

RFC 9110 renamed them from Payload Too Large and Unprocessable Entity. Both names refer to the same codes and older servers still send the old phrases; the table uses the current ones.

What is the difference between key, code and keyCode?

code names the physical key regardless of layout (KeyA is the same key on AZERTY). key is the character or action it produces on the current layout, so it changes with Shift and language. keyCode is a legacy number, deprecated, that differs between browsers for some punctuation; the table notes the Firefox values where they differ.

Why does .ts map to video/mp2t?

Because the registered type for the .ts extension is MPEG transport stream, which predates TypeScript. Servers that map by extension will label a TypeScript file as video unless told otherwise; that is exactly the kind of surprise this table exists to show.

Are the ports the complete IANA list?

No. The IANA registry has thousands of entries, most of them long dead. This table is the ports a developer actually meets: the classic services, the databases and queues, and the default ports of common development servers, which are conventions rather than registrations.