HTTP API

Every reference endpoint is served as a GET /v3/... route on http://127.0.0.1:25503. The machine-readable contract is the bundled OpenAPI file; the human-readable contract is each reference page's HTTP tab.

# Stock EOD across a date range
curl 'http://127.0.0.1:25503/v3/stock/history/eod?symbol=AAPL&start_date=2025-03-03&end_date=2025-03-06'

# Option quote snapshot for one contract
curl 'http://127.0.0.1:25503/v3/option/snapshot/quote?symbol=SPY&expiration=2025-03-21&strike=570&right=C'

# Intraday OHLC bars across a range
curl 'http://127.0.0.1:25503/v3/stock/history/ohlc_range?symbol=AAPL&start_date=2025-03-03&end_date=2025-03-06&interval=1m'

# Trading calendar
curl 'http://127.0.0.1:25503/v3/calendar/open_today'

Parameters

Query parameters use the registry names shown on each reference page — symbol, expiration, strike, right, interval, start_date, end_date, … Date parameters accept both YYYYMMDD and ISO YYYY-MM-DD. Strikes are dollars (570, 17.5); rights accept C / P / call / put.

Response formats

Add format= to any route:

format	Content type	Shape
json (default)	application/json	The envelope below.
csv	text/csv	RFC 4180 with a header row.
ndjson / jsonl	application/x-ndjson	One JSON object per row, newline-delimited.

The JSON envelope:

{
    "header": { "format": "json", "error_type": "null" },
    "response": [ ... ]
}

Failures use one envelope shape across every route — see the error codes table.

Flat files

Whole-universe daily archives stream through dedicated routes with chunked bodies (bounded server memory at any download size):

curl 'http://127.0.0.1:25503/v3/flatfile/option/quote?date=2025-03-03&format=csv' -o quotes.csv

curl -X POST 'http://127.0.0.1:25503/v3/flatfile/request' \
    -H 'Content-Type: application/json' \
    -d '{"sec_type":"OPTION","req_type":"QUOTE","date":"20250303","format":"csv"}' \
    -o quotes.csv

See Flat Files for sizing guidance.

System routes

Method	Route	Description
GET	/v3/system/status	Combined server status.
GET	/v3/system/mdds/status	Historical-channel connection status.
GET	/v3/system/fpss/status	Streaming connection status.
POST	/v3/system/shutdown	Graceful shutdown; requires the X-Shutdown-Token header printed at startup.

Concurrency behavior

Bursts queue, they don't fail. In-flight requests are capped at the HTTP edge (256) and by your subscription tier's concurrency inside the SDK; requests beyond either cap wait in order. Only genuine upstream exhaustion — after the SDK's own retries — surfaces as 503 with Retry-After. A client that disconnects or times out releases its slots immediately.