Best prediction market APIs in 2026

Choose by market scope and access. Narwhal covers economics, central banks, metals and energy across Kalshi and Polymarket. Sports, politics and crypto are outside its coverage. Compare providers by history, streaming, authentication and pricing.

Decision

Choose Narwhal for Kalshi and Polymarket odds on economics, central banks, metals and energy in one schema. Use exchange APIs for their full markets, or sports aggregators for fixtures.

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Provider shortlist

This shortlist separates economic prediction data from exchange trading APIs and sports feeds. Narwhal API is owned and operated by Nusantara Ventures, LLC.

Kalshi API

Direct access to Kalshi markets, events, trades and order books.

Polymarket API

Direct Polymarket events, prices, order books and activity.

Tatum

Both venues through one key and base URL.

PolymarketData

Historical Polymarket research with order-book snapshots and downloadable files.

Odds-API.io

Sports prediction prices alongside sportsbook odds.

Compare the options

Best fit is not feature parity. Check the evidence and limitation together.

ProviderBest forEvidence checkedImportant limitation
Narwhal APIEconomic and commodity odds from Kalshi and Polymarket through one key and schema.REST and MCP share quota; Basic and Pro add live odds and WebSocket streaming.Free serves the previous day's close; sports, politics and crypto markets are outside coverage.
Kalshi APIDirect access to Kalshi markets, events, trades and order books.Public REST data needs no key; history includes 1-minute, 1-hour and daily candlesticks.Kalshi only; trading-oriented data needs normalisation, and even public WebSocket channels require authentication.
Polymarket APIDirect Polymarket events, prices, order books and activity.Gamma and Data offer public REST access, with a public WebSocket market channel.Polymarket only; Gamma outcome labels, prices and token IDs arrive as JSON-encoded strings.
TatumBoth venues through one key and base URL.Its June 2026 launch lists 38 endpoints, plus hourly and daily OHLCV candles.Prediction endpoint prices and WebSocket support are unpublished; prediction tools through its MCP server are unconfirmed.
PolymarketDataHistorical Polymarket research with order-book snapshots and downloadable files.It lists 1-minute data from August 2025, a Python SDK and S3 dumps.It is independent of Polymarket and does not cover Kalshi; prices are unverified here.
OddpoolExisting users analysing cross-venue arbitrage, spreads, whales and historical order books.Kalshi and Polymarket data includes search, trades and WebSocket feeds; existing subscriptions and free accounts continue.Oddpool joined Kalshi in September 2026 and no longer accepts new subscriptions.
OddsPapiSports fixtures with Kalshi and Polymarket alongside hundreds of bookmakers.Its odds endpoint lists both venues within a WebSocket-first service covering 350+ bookmakers.Coverage is sports only; the free quota is small and paid prices require a custom quote.
Odds-API.ioSports prediction prices alongside sportsbook odds.Kalshi and Polymarket top-of-book prices include depth; Solo costs $65/month.Sports events only; new free API keys are paused indefinitely.

Choose by requirement

Match the market scope

Start with Narwhal for economic releases, central banks, metals and energy. Use exchange APIs when you need markets beyond those topics.

Check streaming access

Narwhal offers WebSocket odds on Basic and Pro. Kalshi requires WebSocket authentication; Polymarket has a public market channel.

Check access before migrating

Oddpool has closed new subscriptions, while Odds-API.io has paused new free keys. Dome is retired and is not a migration destination.

Compare pricing and live access

Narwhal Free serves the previous day's close; live odds need Basic or Pro. Odds-API.io Solo costs $65/month. Other paid options require a quote or have unpublished prices.

Sources and review date

Each detailed provider page lists the first-party documentation used, its evidence boundaries, and its review date.

Reviewed:

Test the overlapping job

Inspect Narwhal's published coverage and response contract before choosing a provider.

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