TradeZero Developer Documentation

Welcome. These docs cover the TradeZero REST and WebSocket APIs - the same endpoints that power our ZeroPro, TZ1, and ZeroMobile trading platforms, opened up so you can build your own tools on top of them.

What you can build

TradeZero is a brokerage built for serious traders. The API gives you direct access to equities, multi-leg options, short locates, account data, and real-time streams over one set of credentials.

• Equities trading - place market, limit, and stop orders for stocks, choose your route for direct market access, and cancel resting orders in flight. Start with Equity Trading.
• Options trading - single-leg orders plus a fixed catalog of multi-leg strategies (verticals, straddles, strangles, butterflies, iron butterflies, condors, iron condors, covered calls, and married puts), all using OCC symbology. Start with Options Trading.
• Short locates — quote, accept, and reuse short locates through TradeZero's patented locator API. Start with Short Locates.
• Account and position data - pull current positions, account state, balances, and historical orders via REST. Start with Account Information.
• Real-time streams - subscribe to live P&L and order-status updates over WebSocket so your tools react the moment a fill comes in. Start with WebSocket API.

Where to start

The fastest path from API key to working code is the Quickstart Recipes - ready-to-run examples in Python and TypeScript for the most common flows. A few popular starting points:

• Authenticate & Discover Account - first call against the API, confirms paper vs live, and enumerates routes.
• Place Your First Order - buying-power check, submit, and read back the fill state.
• Locate & Sell Short - the canonical short-side workflow: ETB check, locate quote, accept, short, credit-back.
• Multi-Leg Options Spread - submit a vertical spread end-to-end, including the OCC symbol build and the Mleg envelope.
• Live Account Dashboard - call /account, /positions, and /pnl in parallel and merge into a single periodic snapshot.

If you'd rather skim the reference, the API Reference lists every endpoint with full request and response specs, generated from our OpenAPI definition.

Don't have API access yet? Authentication walks through the TradeZero Portal flow - enabling API trading on your account, signing the required agreements, and generating credentials. Before you poll or burst requests in production, read API Rate Limits for per-endpoint limits and 429 handling.

Two environments

Every endpoint is available in both paper and live environments. Both share the same base URL - https://webapi.tradezero.com - and which environment you hit is determined entirely by the API key pair you send. Build and test against paper, then swap in your live keys to go live - same URL, same auth pattern, same response shapes. A few features differ in the way you'd expect: live accounts have access to real venues and a richer route inventory (SMART, CTDL, SMARTO, SMARTM, ARCA) while paper exposes simulated PAPER / PAPERM routes; locates are live-only (paper-account locate calls return Rejected rows); and the historical-orders archive (GET /orders/start-date/{date}) is empty on paper. See Account Types for the full details.

We're actively expanding the platform - watch the Change Log for releases as they ship.