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Betting exchange

Kalshi

Regulated prediction-market exchange whose API gives access to event-contract markets, order books and trading over REST, WebSocket and FIX; sports contracts are among its markets.

Facts verified against the provider's site on

Commercial use: not disclosedBetting use: not disclosedMixed
Visit official siteOpen API docsCompare
Featured in:⏳ Sports APIs with a free trial💬 Most discussed sports APIs🐙 Most used on GitHub
49

SportDex Score

#61 of 233 sports APIs

See the full ranking →
Popularity
55

Brand demand, developer discussions, GitHub repos and videos

Community & reliability
58

Tone of public discussions, liked vs criticised points, reliability complaints; based on 25+ public discussions.

Transparency
30

Public prices, docs, terms and coverage you can check before calling sales

Developer experience
48

Free access, docs, SDKs, OpenAPI, sandbox, realtime delivery, ecosystem

Computed from public data only; uptime and latency are not measured yet. Enterprise feeds that sell by contract score lower on transparency by design. How the score works

Starting price
Not public
Free access
Not disclosed
Sports
Not disclosed
Live data
Not disclosed
Delivery
Streaming (WebSocket)
Discussions
32 threads
GitHub adoption
1.4k repos

Best for

Developers building trading, market-data or analytics tools on a regulated prediction-market exchange, including sports event contracts.

Prediction-market trading botsOrder book analysisEvent-probability tracking

Not ideal for

Projects wanting conventional bookmaker odds or sports statistics; this is an exchange of event contracts, not a sports data feed.

Limitations to check

  • − Rate limits set by tier, from 200 read tokens per second at Basic
  • − Higher tiers are earned through trading volume
  • − Sports are only some of the markets
  • − Trading fees and unauthenticated read access not confirmed

Written from the provider's own pages (source).

Last checked 2026-11-03

Kalshi at a glance

What is Kalshi best for?
Developers building trading, market-data or analytics tools on a regulated prediction-market exchange, including sports event contracts. Not ideal for: Projects wanting conventional bookmaker odds or sports statistics; this is an exchange of event contracts, not a sports data feed.
How much does Kalshi cost?
Kalshi does not publish prices on the pages we checked.
Does Kalshi have a free tier?
Kalshi has no public free tier, but it offers demo access.
What does Kalshi cover?
Kalshi is a betting exchange. Its data: Trading & risk, Odds.
Does Kalshi have a WebSocket or streaming API?
Yes. Kalshi pushes data continuously: WebSocket.
What do developers say about Kalshi?
Regulated prediction-market exchange with REST, WebSocket and FIX access; sports contracts are used by many arbitrage and trading bots, with clients in C++ and others. Users note the historical API lacks order-book depth, and live-score milestones can show goals later cancelled by VAR. Often paired with Polymarket aggregators.
What are the alternatives to Kalshi?
Close alternatives in the SportDex catalog: Betfair Exchange API, Matchbook Exchange, Polymarket, Smarkets, BETDAQ.

Commercial decision

Pricing & plan limits

No public price list. Check the provider site.

Rate limit tiers (read tokens/sec): Basic 200, Advanced 300, Expert 600, Premier 1,200, Paragon 2,400, Prime 4,800, Prestige 12,000; higher tiers earned via volume. FIX is also offered. Whether market data is readable without auth was not confirmed. Trading fees not captured.

Before choosing a paid plan, confirm

• What counts as one request (per call, per market, per region?)

• What happens when you exceed the quota: blocked or billed

• Whether live and historical data are on your plan

• Whether your use (public app, betting, resale) is licensed

The critical question

Data coverage

Sports
Data types
Trading & riskOdds
Key competitions
Not disclosed
Competitions
Not disclosed
Live / in-play
Not disclosed
Women's competitions
Not disclosed
Betting markets
Not disclosed
Bookmaker regions
Not disclosed
Bookmakers
Not disclosed
History depth
Not disclosed
Update frequency
Not disclosed
Name languages
Not disclosed
ID mapping
Not disclosed

Coverage often depends on the plan; confirm the exact league and season on your plan.

Before you build

Usage rights & access

Commercial use
Not disclosed
Betting products
Not disclosed
Redistribution
Not disclosed
Storing data
Not disclosed
Attribution
Not disclosed
Logos & photos
Not disclosed
Who can buy
Not disclosed
Verification (KYC)
Not disclosed
Not available in
Not disclosed
Only available in
Not disclosed

Developer-ready evaluation

Integration & documentation

Protocols
RESTWebSocket
Formats
JSON
Authentication
api key
SDKs
Not disclosed
OpenAPI spec
Not disclosed
Claimed latency
Not disclosed
Status page
Not disclosed
Sandbox / test keys
Not disclosed
Support
Not disclosed
SLA uptime
Not disclosed
Preview brief
# Integration brief: Kalshi

Goal: build a feature on Kalshi data. Use only the official documentation below as the source of truth.

## Known facts (from SportDex, verify before relying on them)
- Website: https://kalshi.com
- Docs: https://docs.kalshi.com/welcome
- Sports: UNKNOWN — check the docs
- Data: Trading & risk, Odds
- Protocols: REST, WebSocket; formats: json
- Auth: api_key
- Free plan: none listed
- Note: Rate limit tiers (read tokens/sec): Basic 200, Advanced 300, Expert 600, Premier 1,200, Paragon 2,400, Prime 4,800, Prestige 12,000; higher tiers earned via volume. FIX is also offered. Whether market data is readable without auth was not confirmed. Trading fees not captured.

## Verify before writing code
- pricing and request limits
- live update frequency
- whether commercial use is allowed on the plan you pick
- exact endpoint paths, parameters and response fields (read the official docs, do not guess)

## Implementation rules
- Keep the API key on the server (environment variable, backend route or edge function); never ship it to the browser.
- Cache responses and respect rate limits; count how many requests each screen triggers.
- Handle errors explicitly: invalid key, quota exceeded (429), missing fields, empty fixtures, timeouts.
- Start with one demo request and log the raw response before building UI on assumed field names.

Data quality signals

Data source & company

Official partners
Not disclosed
How data is collected
Not disclosed
Certifications
Not disclosed
Payment methods
Not disclosed
Minimum contract
Not disclosed
Country
Not disclosed
Founded
Not disclosed

Reddit · Hacker News · Stack Overflow · GitHub · YouTube

What developers say

Mixeddata qualitycoveragelatencydocs

Regulated prediction-market exchange with REST, WebSocket and FIX access; sports contracts are used by many arbitrage and trading bots, with clients in C++ and others. Users note the historical API lacks order-book depth, and live-score milestones can show goals later cancelled by VAR. Often paired with Polymarket aggregators.

Praised for

  • REST, WebSocket and FIX access
  • Settled markets, trades and candlesticks available
  • Large bot and client ecosystem

Complaints

  • No historical order-book depth for backtesting
  • Live score milestones may reflect cancelled goals

Our summary of public discussions, not a rating. Vendor posts are not counted as user opinion.

Discussions

Shortlist next steps

Alternatives worth comparing

  • Betfair Exchange APIBetting exchange60

    Betfair's developer API for its betting exchange: market prices, order books and bet placement. Free delayed key for development; live key needs an approved application and a one-off fee.

    Free tier
    from £299 one-time30 discussions · 272 repos
  • Matchbook ExchangeBetting exchange30

    UK betting exchange offering a REST API for markets, offers and account data; read-only market data reportedly works without login, trading needs a funded account.

    Multi-sport (40+)
    Price not public0 discussions · 17 repos
  • PolymarketBetting exchange67

    Prediction market exchange whose public Gamma API lists markets and events, including sports, without credentials; separate trading APIs and SDKs exist.

    Free tierMulti-sport (40+)
    Free tier52 discussions · 4.5k repos
  • SmarketsBetting exchange31

    UK person-to-person betting exchange offering a streaming trading API for order entry and market data, with an official Python client.

    ⚡ StreamingMulti-sport (40+)Football (soccer)Horse racing
    Price not public4 discussions · 38 repos
  • BETDAQBetting exchange29

    UK betting exchange whose webservice API is open to verified account holders for a one-off fee, and which offers a streaming commercial API to operators.

    Multi-sport (40+)
    from £250 one-time8 discussions · 3 repos
Betfair Exchange API vs Kalshi

Evidence & transparency

Official sources

Facts were extracted from the provider's own pages on 2026-11-03. Empty fields mean the provider does not say, not that the feature is missing. How we know