Can You Trade Tennis on Polymarket? 2026 Guide

Yes. Polymarket lists tennis event markets you can trade — 400+ live moneyline markets were open on 2026-08-18 during the 2026 Cincinnati Open swing (ATP, WTA, Challengers, ITF, and US Open futures). The market prices are public and keyless; the live match data to trade on comes from a free API. Both sides can be read and automated in Python.

This is a developer-oriented answer. If you just want the build steps, jump to the pillar tutorial: How to build a Polymarket tennis trading bot (Python). This page covers the questions that come before the build: what exists, what data you need, whether there is an API, and whether any of it can be automated.

What kind of tennis markets exist on Polymarket?

The common shape is a moneyline: a two-outcome market on who wins a match, priced in shares from $0.00 to $1.00 that settle at $1.00 for the correct outcome. A price of 0.62 reads as a 62% implied chance. You will also find tournament-winner futures (for example, "Winner of the US Open"). Markets span the tour ladder — Grand Slams down through Challengers and ITF events — so coverage is much wider than just the marquee matches.

Polymarket exposes all of this through its public Gamma API at https://gamma-api.polymarket.com. Tennis markets carry tag id 864. No key, wallet, or account is needed to read prices.

# Count the tennis events currently listed on Polymarket (keyless)
curl -s "https://gamma-api.polymarket.com/events?tag_id=864&closed=false&limit=100" \
  | python3 -c "import sys,json; print(len(json.load(sys.stdin)), 'tennis events')"

Is there an API to trade tennis on Polymarket?

There are two distinct APIs, and keeping them separate is the whole game:

1. Market prices — Polymarket Gamma API (https://gamma-api.polymarket.com). Free, keyless, read-only. Gives you the questions, outcomes, and current prices. This is where the "market" lives.
2. Live match state — Live Tennis API (https://api.livetennisapi.com/api/public/v1). This is tennis reality: who is serving, the current score, rankings and Elo. A free key covers live matches and scores. A price without live state is half a signal, which is why a trading bot reads both.

Order execution — placing a trade, holding funds — is a third thing entirely, handled by Polymarket's own on-chain CLOB client and your wallet. More on that below.

import httpx

GAMMA = "https://gamma-api.polymarket.com"

# Read live tennis market prices from Polymarket (no key required)
r = httpx.get(f"{GAMMA}/markets",
              params={"tag_id": 864, "closed": "false", "limit": 5})
for m in r.json():
    print(m["question"], "->", m.get("outcomePrices"))

What data do you need to automate a tennis trade?

Three layers, and the free tier gets you the first two:

• Market discovery — which tennis markets are open right now, and at what price. Polymarket Gamma, keyless.
• Live match state — the score, the server, whether it is a break point. Live Tennis API, free tier. FREE covers GET /matches?status=live and GET /matches/{id}/score.
• Execution — turning a signal into an order. Your responsibility, via Polymarket's official py-clob-client and your own wallet.

Here is the free live-state read from the Live Tennis API:

import httpx

BASE = "https://api.livetennisapi.com/api/public/v1"
HEADERS = {"X-API-Key": "YOUR_FREE_KEY"}  # get one: livetennisapi.com/subscribe/free

live = httpx.get(f"{BASE}/matches", params={"status": "live"}, headers=HEADERS).json()
for match in live.get("matches", []):
    print(match["id"], match["home"]["name"], "vs", match["away"]["name"])

The free tier stops at the current state of a live match, which is exactly what a real-time signal needs. Completed-match history and point-by-point tape are Basic ($9.99/mo); win-probability analysis, per-point events, and the WebSocket stream are Ultra ($99.99/mo). You do not need any paid tier to start.

Can a tennis trading bot be automated?

The read and signal side — yes, fully. Discovering markets, matching each to the right live match, and joining the price to the live score is exactly what our open-source toolkit does. livetennisapi/polymarket-tennis (MIT) is observe-only: no orders, no wallets, no keys. It is the reference starting point.

pip install "polymarket-tennis @ git+https://github.com/livetennisapi/polymarket-tennis"

# Discover open tennis markets, then join a market to its live score line
pmtennis discover --matches-only --moneyline-only
pmtennis watch atp-lehecka-fils-2026-08-17

from polymarket_tennis import (
    GammaClient, LiveTennisClient,
    discover_tennis_markets, match_market, build_view,
)

with GammaClient() as gamma, LiveTennisClient(api_key="YOUR_FREE_KEY") as lta:
    markets = discover_tennis_markets(gamma, market_types={"moneyline"},
                                      matches_only=True)
    candidates = lta.live_matches() + lta.fixtures()
    for market in markets:
        decision = match_market(market, candidates)   # name + date heuristics; None if ambiguous
        if decision is None:
            continue
        view = build_view(market, decision.match)      # price + live score, server, break-point flag
        print(view.render())

The execution step — placing the order — is where automation becomes your code and your risk. That is a deliberate line: our tooling and this guide teach the read side and never place trades, hold funds, or give financial advice. When you are ready to execute, Polymarket's official py-clob-client is the sanctioned path, and the wallet and private keys are yours to manage.

Is it free to start trading tennis on Polymarket?

Reading everything you need to build and paper-test a signal is free. Polymarket's Gamma prices are keyless, and the Live Tennis API's free tier (30 req/min, 100 req/day) covers live matches, scores, players, rankings, Elo, and fixtures — no card required at livetennisapi.com/subscribe/free. You only reach for a paid tier if your strategy needs history, point-by-point tape, or win-probability analysis. Placing real trades involves funding a wallet on Polymarket, which is separate from any API cost.

What happens on a retirement or walkover?

This is the question that catches first-time tennis traders, and the answer differs by venue: on polymarket.com a walkover (withdrawal before the start) resolves 50-50 and a mid-match retirement pays the player who advances; Polymarket US settles a pre-serve walkover at the last fair market price (ITF matches at $0.50); Kalshi resolves ATP/WTA pre-start cases at a "fair price" and ITF at $0.50. We keep the exact wording from each venue, dated, in Polymarket & Kalshi tennis retirement/walkover rules (2026). Kalshi's tennis series, ticker format and keyless API reads are in Kalshi tennis: live scores, series tickers & API.

Next step

For the manual map — where the markets live on the site, how a match page is built, and a sensible first week — see How to trade tennis on Polymarket (2026).

If the answer you came for is "yes, and here's how," the end-to-end build — discover markets, match them to live matches, read live state, and where execution plugs in — is the pillar tutorial: How to build a Polymarket tennis trading bot (Python).