nautilus-fyers 0.3.1

Fyers (Indian broker) adapter for NautilusTrader — REST + WebSocket bridge for NSE/BSE live data and execution

nautilus-fyers

A NautilusTrader-style adapter for Fyers (Indian broker, API v3), bridging Fyers REST + WebSocket APIs for live market data and execution on NSE/BSE instruments.

Built following the phased plan in fyers_nautilus_adapter_plan.md.

Architecture

Python layer  nautilus_fyers/   framework-neutral clients, config, auth
Rust core     crates/adapters/fyers/            wire models, enums, parsing, protocol state

The Python layer is fully functional standalone (stdlib only; websockets needed for live streaming). The Rust crate mirrors the NautilusTrader adapter crate layout (models/enums/parse per module, no async runtime dependency) so it can later be vendored into the nautilus_trader workspace and bound via PyO3.

Component	Module	Status
Instrument provider (symbol master, positional + header CSV)	providers.py	✅ tested
OAuth2 auth flow + daily token refresh	auth.py	✅ tested
REST client (quotes, depth, history, orders, positions, holdings, funds, tradebook)	http.py	✅ tested
Rate limiting (token bucket, 10 req/s) + retries with backoff	http.py	✅ tested
Real-time streaming (official SDK decoder, asyncio bridge, [stream] extra)	streaming.py, data.py	✅ live-verified
Data socket protocol state (modes, reconnect + subscription restore)	transport.py, ws.py	✅ tested
Order socket (order/trade/position updates, replay dedup)	transport.py, execution.py	✅ tested
Order lifecycle (submit/modify/cancel/cancel-all) + reconciliation reports	execution.py	✅ tested
NautilusTrader TradingNode integration (factories, live clients, Equity/Option/Future instruments, reconciliation reports, account state)	nautilus.py	✅ tested against nautilus_trader 1.230
Rust core (models, enums, parse, protocol state)	crates/adapters/fyers	✅ tested

Quick start

1. Get an access token (daily)

export FYERS_CLIENT_ID="ABCD1234-100"
export FYERS_SECRET_KEY="..."
python examples/generate_access_token.py
export FYERS_ACCESS_TOKEN="<printed token>"

2. Stream live quotes

pip install "nautilus-fyers[stream]"   # real-time streaming (official SDK decoder)
python examples/basic_data_subscription.py

from nautilus_fyers import FyersDataClientConfig, QuoteEvent, create_data_client

client = create_data_client(FyersDataClientConfig.from_env())
client.on(QuoteEvent, my_async_handler)
await client.subscribe_quotes(["NSE:RELIANCE-EQ"])
await client.connect()

3. Trade

from nautilus_fyers import FyersExecClientConfig, create_execution_client

exec_client = create_execution_client(FyersExecClientConfig.from_env())
await exec_client.connect()   # order socket: real-time order/trade/position updates
response = await exec_client.submit_order(
    "NSE:SBIN-EQ", "BUY", 1, order_type="LIMIT", limit_price=795.0,
)
await exec_client.cancel_order(response["id"])
state = await exec_client.reconcile()  # orders + positions + trades

See examples/ for complete scripts, including a safe live order-lifecycle test that uses a far-from-market limit order (Fyers has no paper-trading sandbox).

4. Run a NautilusTrader TradingNode

pip install "nautilus-fyers[nautilus,live]"

from nautilus_trader.config import TradingNodeConfig
from nautilus_trader.live.node import TradingNode
from nautilus_fyers.nautilus import (
    FyersDataClientConfig, FyersExecClientConfig,
    FyersLiveDataClientFactory, FyersLiveExecClientFactory,
)

config = TradingNodeConfig(
    trader_id="FYERS-TRADER-001",
    data_clients={"FYERS": FyersDataClientConfig(client_id=..., access_token=...)},
    exec_clients={"FYERS": FyersExecClientConfig(client_id=..., access_token=...)},
)
node = TradingNode(config=config)
node.add_data_client_factory("FYERS", FyersLiveDataClientFactory)
node.add_exec_client_factory("FYERS", FyersLiveExecClientFactory)
node.build()
node.run()

Strategies address instruments as NSE:SBIN-EQ.FYERS. Execution updates (accepted/filled/cancelled/rejected, partial fills, account state, reconciliation reports) flow through the real-time order socket; quote ticks are synthesized by REST polling (configurable quote_poll_interval, default 1s) until the binary HSM market-data codec is implemented.

→ Full guides:

• docs/nautilus_integration.md — live trading: instrument loading, order-type mapping, product types, restarts/reconciliation, and a complete SMA crossover strategy (examples/sma_crossover_live.py)
• docs/backtesting.md — backtesting: Fyers history → Nautilus Bars → BacktestEngine, with history-endpoint limits and a validated runnable example (examples/backtest_sma.py)

5. Load instruments

from nautilus_fyers import FyersInstrumentProvider

provider = FyersInstrumentProvider()
await provider.load_all_async({"segment": ["CM", "FO"]})  # downloads the daily symbol master
instrument = provider.get("NSE:RELIANCE-EQ.FYERS")

Development

python3 -m venv .venv && .venv/bin/pip install -e ".[dev]"
.venv/bin/pytest                      # Python tests
cargo test --manifest-path crates/adapters/fyers/Cargo.toml   # Rust tests

All test fixtures live under test_data/ and mirror real Fyers API payload shapes (http_*.json for REST, ws_*.json for WebSocket frames, plus a positional symbol-master CSV).

Implementation notes & deviations from the plan

• Authorization header: Fyers v3 expects Authorization: <client_id>:<access_token>, not Bearer <token> as sketched in the plan. FyersConfig.authorization() builds the correct form.
• Modify order uses HTTP PATCH (matching the official fyers-apiv3 SDK), not PUT.
• Endpoint paths: trading endpoints live under /api/v3/... and market data under /data/... on api-t1.fyers.in; the plan's single /orders, /data/quotes paths were normalized accordingly.
• WebSocket protocol (verified against the official fyers-apiv3 SDK source): auth travels on the websocket handshake as an authorization: <client_id>:<token> header — there is no JSON "CONNECT" frame. The order socket is wss://socket.fyers.in/trade/v3 (JSON), the data socket is wss://socket.fyers.in/hsm/v1-5/prod (binary "HSM" protocol that first requires symbol→HSM-token conversion via /data/symbol-token), and keepalive is a literal "ping" text frame. Raw order-socket frames use short field names (qty_filled, price_limit, tran_side, ...) which the event parsers accept alongside the mapped names.
• Binary data frames (HSM): solved by wrapping the official fyers-apiv3 SDK — the broker's own maintained decoder — as an optional streaming backend (pip install "nautilus-fyers[stream]"), the same pattern NautilusTrader's IBKR adapter uses with ibapi. With the extra installed, subscribe_quotes() delivers true streaming ticks; without it, quotes fall back to 1s REST polling. A native asyncio HSM codec remains a possible future replacement.
• Native Nautilus objects: NautilusTrader is an optional dependency. The core adapter emits neutral event dataclasses (QuoteEvent, OrderEvent, ...); nautilus_fyers.nautilus (imported only when NautilusTrader is installed) provides full TradingNode wiring — LiveMarketDataClient/LiveExecutionClient subclasses, Equity/Option/Future instrument conversion, order lifecycle events with partial-fill deltas, reconciliation reports, and account state from /funds.
• Rust core: the crate contains the domain layer (models, enums, parsing, subscription and dedup state) with fixture-driven unit tests, but no HTTP/WebSocket I/O runtime — that arrives when the crate is vendored into the NautilusTrader workspace where nautilus-network provides the clients.

Restarts & carryforward

Order ownership survives restarts through three mechanisms:

1. Every order is submitted with a Fyers orderTag carrying a sanitized copy of the Nautilus ClientOrderId, and the tag round-trips in order-book rows and socket frames.
2. On connect, the execution client seeds its venue-order map and cumulative fill counters from the venue order book — so socket replays of already-filled orders never double-fill, and fills that happened while you were offline reconcile as deltas.
3. Reconciliation reports resolve ClientOrderId from the returned tag by matching against cached orders.

For step 3 to work across a process restart, enable Nautilus cache persistence so cached orders survive (otherwise recovered orders are adopted as external/venue orders — safe, but not attributed to your strategy):

from nautilus_trader.config import CacheConfig, DatabaseConfig

config = TradingNodeConfig(
    ...,
    cache=CacheConfig(database=DatabaseConfig(type="redis", host="localhost", port=6379)),
)

Positions carried overnight (CNC) are recovered via position status reports on every start.

Symbol format

Fyers symbols look like NSE:RELIANCE-EQ, NSE:NIFTY25JUL25000CE, BSE:HDFCBANK-A. Instrument ids append the venue: NSE:RELIANCE-EQ.FYERS.

Rate limits & tokens

• REST: ~10 requests/second (enforced client-side by a token bucket).
• Access tokens expire daily (~6 AM IST). Use TokenManager with a refresh callback, or re-run examples/generate_access_token.py. Refresh tokens last ~15 days.