The four groups
REST verbs (HTTP methods)
GET · POST · PUT · PATCH
gRPC method shapes
UNARY · SERVER STREAM · CLIENT STREAM · BIDIRECTIONAL
OAuth 2.0 grant types
AUTHORIZATION CODE · CLIENT CREDENTIALS · PASSWORD · REFRESH TOKEN
Words that precede KEY
API · MASTER · FOREIGN · FLORIDA
Why this puzzle works
API is purple but the puzzle's *title* is 'API contract' — sleight of hand. PASSWORD is OAuth grant terminology (the 'password' grant, also deprecated since OAuth 2.1) and not the everyday meaning. FLORIDA is the unmissable wordplay tell (Florida Keys); once you see it, the rest of purple collapses.
How to read a Connectle without solving it
A code-themed grouping puzzle rewards counting as much as recognition. Start by listing every plausible group, then notice which tiles appear in two lists. Whichever group has exactly four unambiguous members is your anchor — solve it first and the rest of the board collapses by elimination. The hardest tier (purple) is almost always wordplay: tiles that share a prefix or suffix, not a concept. If a tile feels orphaned, ask whether the same word could follow or precede a common engineering word like root, stack, cache, or queue.