Gemini's symbol mapping — the family's first genuinely lossy one.

Gemini's native symbol is lowercase and separatorless: btcusd, aavegusd, jitosolsol. Canonical is BASE-QUOTE. So unlike Coinbase, where the conversion is effectively identity, here both directions do real work and one of them can be wrong.

Why the quote list is ordered longest-first, and why here it bites

With sep: "" there is no separator to split on, so CanonicalPair recovers the base by matching a known quote suffix. The list is consulted in order, so a shorter quote that is also the tail of a longer one will win if it is checked first — and Gemini has three overlapping pairs of exactly that shape:

AAVEG is not an asset. A symbol split that way matches no catalogue entry and collects nothing, silently — the same shape of failure as a wrong timeframe, one layer down.

Of the 346 symbols live on 2026-08-28, 157 end in a quote that is a suffix of another quote (80 GUSD + 77 RLUSD). This is not a precaution on this venue; it is 45% of the catalogue.

The quote list was derived, not assumed

Taken from the live /v1/symbols list on 2026-08-28 by tallying suffixes and then chasing what did not match. Two symbols were left over — jitosolsol and efilfil — which is how SOL and FIL got here. Guessing the list from the well-known quotes would have produced exactly those two silent mis-splits.

Perpetuals are not spot pairs and do not round-trip

Thirteen symbols carry a perp suffix (avaxgusdperp). They end in no quote, so they take the :nomatch path and are returned uppercased and unsplit. That is deliberate: this package declares supported_instrument_types: [:spot], and inventing a canonical spot pair for a perpetual would be a substitution. Rest.get_symbols/1 filters them out rather than emitting a symbol the rest of the family cannot interpret.

Downcase on the way out

CanonicalPair.to_exchange/2 returns uppercase (BTCUSD). Gemini's REST accepts either case, but /v1/symbols returns lowercase and the WebSocket stream names are lowercase — btcusd@bookTicker. So the exchange form is downcased here, once, rather than at each of the several call sites that would otherwise have to remember.