DpExchange.Gemini.Rest (DpExchangeGemini v0.1.1)

Gemini's REST surface — internal. The facade's market-data callbacks are served here.

Every endpoint below was measured against the live venue on 2026-08-28. Where the measurement disagreed with Gemini's documentation, the measurement won and the divergence is recorded in docs/reference/gemini/.

The candle window is fixed and every parameter is ignored

/v2/candles/{symbol}/{time_frame} takes no bounds. limit, start and end are accepted and discarded — three requests differing only in those returned byte-identical responses. Each width serves a fixed window:

Width sent	Bars	≈ span
`1m`	1440	1 day
`5m`	2015	7 days
`15m`	1343	14 days
`30m`	1439	30 days
`1hr`	1463	61 days
`6hr`	367	92 days
`1day`	364	1 year

So a range is honoured by filtering here, and a range the window cannot cover is an error rather than a short answer. Handing back 364 daily bars to a caller who asked for five years is the family's named failure mode in its quietest form: every value real, only the meaning wrong.

Neither ticker carries a quote timestamp, so the venue's own clock is used

/v1/pubticker returns a timestamp, but it is inside the volume object — it stamps the 24-hour volume window, updates about once a minute, and is not when the bid and ask were true. /v2/ticker carries no timestamp at all. Using either as the quote time would be a substitution of exactly the kind this family exists to stop, and the host adapter does something worse: parse_timestamp(nil) returns DateTime.utc_now(), so a quote with no venue time gets the client's clock and looks perfectly fresh.

This package uses the HTTP Date response header — the venue's own statement of when it served the answer, which bounds the quote's age and is not our clock. When that header is absent the request fails with {:error, :missing_venue_timestamp} rather than returning a quote whose freshness cannot be stated.

Summary

Functions

base_url(opts \\ [])

Base URL, overridable per process for tests through Core.Config.

get_historical_prices(symbol, timeframe, range, opts)

Candles for a symbol and canonical timeframe, filtered to range.

get_market_overview(opts)

Every pair with its last price and 24-hour change, in one call.

get_order_book(symbol, opts)

A price-level snapshot for one symbol.

get_price(symbol, opts)

Best bid, best ask and last trade for one symbol.

get_symbols(opts)

Every spot symbol the venue lists, canonical.

quantization(symbol, opts)

The increments and minimum the venue will actually accept for a symbol.

timeframes()

Canonical timeframes this venue serves, shortest first.

Functions

base_url(opts \\ [])

@spec base_url(keyword()) :: String.t()

Base URL, overridable per process for tests through Core.Config.

get_historical_prices(symbol, timeframe, range, opts)

@spec get_historical_prices(String.t(), String.t(), keyword(), keyword()) ::
  {:ok, [map()]} | {:error, term()} | {:refused, term()}

Candles for a symbol and canonical timeframe, filtered to range.

range accepts :start and :end as DateTimes. Both are optional; with neither, the venue's whole fixed window is returned.

Refuses rather than truncating:

an unknown width → {:error, {:unsupported_timeframe, width}}
a :start older than the window can reach → {:error, {:range_unavailable, …}}

get_market_overview(opts)

@spec get_market_overview(keyword()) :: {:ok, map()} | {:error, term()}

Every pair with its last price and 24-hour change, in one call.

/v1/pricefeed is the only endpoint here that describes the whole catalogue at once, which is what makes an overview affordable — the alternative is one request per symbol across 346 symbols, which is not an overview, it is a rate-limit incident.

get_order_book(symbol, opts)

@spec get_order_book(
  String.t(),
  keyword()
) ::
  {:ok, DpExchange.Core.Types.OrderBook.t()}
  | {:error, term()}
  | {:refused, term()}

A price-level snapshot for one symbol.

Each level carries the venue's own timestamp, so unlike a quote there is nothing to derive: the book's time is the newest level's time.

get_price(symbol, opts)

@spec get_price(
  String.t(),
  keyword()
) ::
  {:ok, DpExchange.Core.Types.Quote.t()} | {:error, term()} | {:refused, term()}

Best bid, best ask and last trade for one symbol.

Timestamped from the venue's Date response header — see the module doc for why not from the payload.

get_symbols(opts)

@spec get_symbols(keyword()) :: {:ok, [String.t()]} | {:error, term()}

Every spot symbol the venue lists, canonical.

Perpetuals are excluded. They are real instruments and the venue lists them alongside spot pairs, but this package declares supported_instrument_types: [:spot], and a perpetual has no canonical BASE-QUOTE form — emitting one would invent a spot pair that does not exist.

quantization(symbol, opts)

@spec quantization(
  String.t(),
  keyword()
) :: {:ok, map()} | {:error, term()} | {:refused, term()}

The increments and minimum the venue will actually accept for a symbol.

From /v1/symbols/details/{symbol}, which is also the source behind the venue's own published minimums table — that page states it fetches this endpoint live.

tick_size is the base-asset increment and quote_increment the price increment. They are not interchangeable and the names do not say so: for btcusd, tick_size is 1.0e-8 BTC while quote_increment is 0.01 USD.

timeframes()

@spec timeframes() :: [String.t()]

Canonical timeframes this venue serves, shortest first.