IDs and numbers¶

How a person reads an ID, a number or a unit: tail numbers, units, ratios and money.

Tail-number IDs¶

Give every object a person can point at a tail number: product prefix, optional type, short code; uppercase, hyphenated. HGR-7Q2K sandbox, FDK-EXP-0142 experiment, TWR-APR-0391 approval, TWR-RCPT-88A1 receipt.
Set IDs in af-id (DM Mono 500). Never lowercase, wrap or truncate an ID; truncate the description beside it. The fleet board may show the code alone (7Q2K) because the pool header carries the prefix.
Lead with the ID: "HGR-0PZ4 failed at test", not "Test failed for sandbox HGR-0PZ4".
Derive the code from the real ID: a hash written in Crockford base32 (0-9, A-Z without I L O U), four characters. When two objects on the same page share a code, lengthen both until they differ. Keep the real ID on hover (title), on copy, and in URLs and the API.
Kind segments: the product's main object has none (HGR-7Q2K is a sandbox). Others use a short word: JOB, SES session, APR approval, SNAP snapshot, REQ request, RUN, BLD build, TOK token, EXP experiment, RCPT receipt. Things people name (environments, credentials, named sessions) keep their names.
Where a machine reads the text (commands, commit trailers, logs), keep the real ID. Where a person reads it (Slack, PR comments), lead with the tail number and give the real ID beside it.

Use tabular figures wherever numbers stack (data style, af-num, af-mono). Right-align numeric columns.
Put a space between number and unit: 14.0 s, 41 min, 2 vCPU, 48.6k tokens. No space before % or after a currency sign: 61%, $1.18.
Elapsed clocks as 00:41:07. Span durations in seconds with one decimal. Relative time axes run -60 min to now.
Money: two decimals in tables ($0.42), whole units in headlines ($142). Group thousands: 2,481.
Ratios in words: 22 of 24 slots, 38 of 41. Never 38/41.
Show zero as a number (0, $0.00). Use an em dash only for "not applicable".

Part of the brand book. See also Status, Data and Products.