Prediction markets

Tennis data for Kalshi and Polymarket traders

Live Tennis API gives you live match state: score, server, status and outcome. It covers ATP, WTA, Challenger and ITF matches over REST and WebSocket. Start with a free API key. Your code can read what happened in the match before it decides anything about a market.

Use a free API key for REST access to live matches and scores. WebSocket access is on the Ultra plan. Use REST to request match state, or subscribe to the WebSocket feed for updates. Your application supplies the logic that connects that state to a Kalshi or Polymarket market.

What you get from the API

status: the match lifecycle state.
event_status: labels include Finished, Retired, Cancelled, Walk Over, Postponed and Interrupted.
outcome: completed, retired, walkover, default, abandoned or unresolved. It can be null before there is an outcome.
withdrew: identifies the withdrawing player when the result supports it. An absent value is not proof that nobody withdrew.
Live score: the available set, game and point score.
Server: the player serving, when supplied.

Read the API reference for field definitions and response shapes. Get a free API key, then check pricing for plan limits and WebSocket access.

Keep the match lifecycle and outcome separate in your code. A match can stop for reasons that matter to a market contract. A final score alone does not explain a retirement or walkover. Keep missing values missing when you store a response, so a later calculation does not treat an unknown result as a completed match.

Guides

Start with the rules articles if your application handles matches that stop early. Then choose the integration guides for the market you use. The examples connect tennis data to market data and show where your own application logic belongs.

Rules

These articles discuss retirements, walkovers and interruptions. Read them alongside the rules text on the specific market you are inspecting.

Kalshi

Read about tennis series and tickers before building the connection between a market and a match. The bot guide follows with the data-reading side of that application.

Polymarket

The API overview explains where market discovery and orders fit. The matching guide covers pairing a market with the right tennis match. Use those checks before attaching live scores to a market in your application.

What this is not

Nothing on this page is advice. Live Tennis API is not affiliated with Kalshi or Polymarket. Each market's own rules text decides settlement. A match outcome from the API describes the tennis result. Your application must read the market contract to understand how that result applies.

Last updated 13 November 2026.