Status: acquired by Polymarket — APIs retired April 28, 2026

Polymarket acquired Dome on February 19, 2026 (Dome was a Y Combinator F25 startup), and all standalone Dome APIs reached end-of-life on April 28, 2026. The api.dome.fi / api.domeapi.io endpoints no longer serve traffic. Dome directs developers to Polymarket’s native APIs for ongoing prediction market data. For the same unified, multi-platform interface Dome offered, pmxt is an actively maintained open-source aggregator (Polymarket + Kalshi + others). The reference below is retained for historical context; do not build new integrations against Dome.

Overview

Dome provided unified APIs and SDKs that normalized prediction market data from multiple platforms into a single interface. Instead of integrating separately with Polymarket’s CLOB API, Kalshi’s REST API, and other platform-specific endpoints, developers could use Dome’s single API key and standardized data format to access markets across the ecosystem. (Since April 28, 2026, this functionality is no longer available from Dome directly — see the status note above.)

Key Features

Multi-platform normalization — Access data from Polymarket, Kalshi, Limitless, and other platforms through one API with consistent schemas.

Real-time and historical data — Live market prices and order books plus historical data for backtesting agent strategies.

Single API key — One authentication credential for all platforms, simplifying agent configuration.

Standardized format — Consistent JSON schemas across platforms, eliminating the need to write platform-specific parsers.

Agent-Friendliness

AspectRating
API qualityGood — clean REST with consistent schemas
Multi-platformExcellent — single key for multiple exchanges
Data coverageGood — real-time and historical
JSON supportYes — standardized across platforms
Use caseData consumption and cross-platform comparison

Migration (the Dome API is retired)

The original Dome endpoint (https://api.dome.fi/v1) was decommissioned on April 28, 2026 and returns no data. The maintainers of the open-source pmxt aggregator publish a Dome migration guide and an automatic codemod that rewrites Dome calls to pmxt:

# Automatically migrate a Dome codebase to pmxt
npx dome-to-pmxt ./src

pmxt (MIT, no API key) exposes Polymarket, Kalshi, Limitless, and other venues through one interface:

# pip install pmxt  —  https://github.com/pmxt-dev/pmxt
import pmxt

api = pmxt.Exchange()

# Search an event, then read a specific market's price
events = api.fetch_events(query="bitcoin 100k")
market = events[0].markets[0]
print(f"{market.title} — {market.yes.price}")

For Polymarket-specific data and order execution, use Polymarket’s native APIs directly. The single-integration advantage Dome offered now lives in maintained open-source aggregators rather than the retired Dome service. See pmxt’s Dome API alternative guide for a full migration walkthrough.

When to Use Dome vs. Direct APIs

ScenarioUse DomeUse Direct APIs
Cross-platform price comparison✓
Arbitrage scanning across exchanges✓
Platform-specific advanced features✓
Order placement and execution✓
Historical data for backtesting✓
Minimizing integration maintenance✓

Dome focused on the read side — market discovery, price comparison, and historical data. That same split applies to its successors: use an aggregator such as pmxt for unified cross-platform reads, and direct platform APIs (Polymarket CLI or Kalshi API) for order execution.

Pricing

Not applicable — the Dome APIs reached end-of-life on April 28, 2026. The recommended open-source replacement, pmxt, is MIT-licensed and free (self-host or use its hosted API), and Polymarket’s native APIs follow Polymarket’s standard access terms.

Best For

The use case Dome served — arbitrage agents comparing prices across Polymarket and Kalshi, and any agent scanning the whole prediction market ecosystem without maintaining separate integrations — is now best served by the open-source pmxt aggregator, since the Dome APIs are no longer available.