API Reference¶

dccd v3 is a hexagonal architecture: a pure, synchronous domain with no I/O, an async transport layer, exchange sources, storage, an application layer of operations, and thin interfaces (CLI · HTTP API · UI · Python Client). See Architecture for the big picture.

Each object below links to its own page with the full signature, parameters and examples.

Client¶

The one-stop async facade — most users only need this.

Client

Async context manager facade for dccd v3.

Domain¶

Pure, synchronous value objects and helpers — no I/O. All timestamps are nanoseconds UTC (int64).

`symbol.Symbol`	Canonical trading pair (base/quote, spot by default).
`types.DataType`	Core data types supported by dccd v3.
`records.OHLCBar`	One OHLCV candle bar.
`records.Trade`	Single trade (tick).
`records.OrderBookSnapshot`	A complete (or delta) order book state at a point in time.
`records.OrderBookLevel`	One price level in an order book.
`capability.Capability`	Declares one atomic capability of a source adapter.
`dataset.DatasetId`	Unique identifier for a dataset (exchange × symbol × type × span).
`dataset.Provenance`	Dataset-level lineage metadata (stored in Parquet metadata, not per-row).

Pure transforms and time helpers:

transforms.aggregate_ohlc

Aggregate trades into OHLC bars of span seconds.

Sources¶

One adapter per exchange, implementing the fine-grained Source protocols, resolved through a registry. See Exchanges for capabilities and fidelity.

`registry.SourceRegistry`	Maps exchange names to source adapter instances.
`binance.BinanceSource`	Binance adapter for OHLC, trades and order book.
`coinbase.CoinbaseSource`	Coinbase adapter.
`kraken.KrakenSource`	Kraken source adapter.
`bybit.BybitSource`	Bybit adapter.
`okx.OKXSource`	OKX adapter — uses history-candles for deep OHLC, history-trades for deep trades.
`bitfinex.BitfinexSource`	Bitfinex adapter — 10000 bars/trades per request (largest limit).
`bitmex.BitMEXSource`	BitMEX adapter — bucketed (1m/5m/1h/1d) OHLC, full trades history.

Transport¶

Async I/O building blocks shared by every adapter.

`http.AsyncHTTPClient`	Thin wrapper around httpx.AsyncClient with retry/backoff.
`ws.WebSocketBase`	Base async WebSocket client with exponential reconnect.
`ratelimit.RateLimiter`	Global per-exchange rate limiter.
`paginate.paginate_ohlc`	Paginate OHLC bars forward using declared Capability.
`paginate.paginate_trades`	Paginate trades by cursor, draining the `[start_ns, end_ns]` window.

Storage¶

Parquet datasets (ns timestamps, provenance, per-type dedup) and the run history.

`parquet.ParquetStore`	Read/write interface for a single DatasetId.
`runs_sqlite.RunsStore`	Append-only SQLite store for JobRun records.
`migrate.migrate_parquet_to_ns`	Migrate all Parquet files under data_path to the canonical v3 schema.

Application¶

The operations and orchestration that wire domain, sources and storage together.

`operations.backfill`	Backfill historical data from a source to the Parquet store.
`operations.stream`	Stream live data continuously until stop_event is set.
`operations.read`	Read stored data for target in the given nanosecond range.
`operations.inventory`	Return a list of dataset descriptors for all stored data.
`scheduler.Scheduler`	Orchestrates JobSpecs (intervals → backfill; supervised → streams).
`config.AppConfig`
`config.JobConfig`	YAML job definition — more human-friendly than JobSpec.
`jobs.JobSpec`	Declarative job definition.
`events.EventBus`	Simple pub-sub event bus for operation progress/log/status events.

Interfaces¶

api.app.create_app

Create and return the FastAPI application.