Best prediction market API, ranked by live latency and uptime
Warm price endpoint latency of five prediction market venue APIs from three regions, plus a live uptime panel that answers whether each API is up right now.
Read this carefully
Uptime here means our probes succeeded from three specific regions at a polite request rate. A venue can be up for us and degraded for you, especially during regional network incidents, and a brief blip between probe cycles can go unrecorded. Treat the panel as a measured signal, not a guarantee.
When the Polymarket API stops answering, the only pages that notice are downdetector clones aggregating complaints. None of them actually probe the API. This benchmark does. A harness in three regions requests the price endpoint of Polymarket, Kalshi, Limitless, Manifold and Myriad every 5 seconds over warm connections, records every round trip, and publishes two things venue status pages do not: a latency leaderboard ranking the best prediction market API by measured p50, and a per venue uptime panel computed from the same probes. If you are here to check whether the Polymarket API is up right now, the uptime panel below is a direct measurement, refreshed continuously, not a complaint counter. If you are choosing which venue API to build on, the leaderboard ranks them by the latency of the one endpoint every integration hits hardest, the single market price quote.
Methodology
Each venue's price endpoint, the single market quote that every bot, dashboard and integration polls hardest, is probed every 5 seconds (7 on Manifold) from us-east, eu-west and Singapore over a warm keep alive pool. Every sample records full round trip, time to first byte and a CDN cache flag from the response headers. Latency aggregates exclude CDN cache hits, because a cached read measures the edge, not the API, and Manifold's entire API sits behind a 5 second cache. The headline is the 24h p50 of warm, non cached price requests. Uptime per venue is the 24h and 7d average of a health gauge derived from the same probes, so "is this API up" is answered by direct measurement from three regions rather than by user reports. Samples that fail because our pinned market expired are classified probe_invalid and never count against the venue.
Frequently asked
Is the Polymarket API up right now?
Check the uptime panel above, it is a direct measurement, not a complaint counter. Our harness requests Polymarket's CLOB midpoint endpoint every 5 seconds from three regions (US East, EU West, Singapore) and computes a health gauge from the outcomes. The 24h uptime figure shown for Polymarket is the average of that gauge, so 100 percent means every probe cycle in the last 24 hours succeeded from every region. If Polymarket is having a partial outage, you will usually see it first as a dip in one region's health or a spike in the latency series before it shows as a hard failure.
What is the best prediction market API?
By measured latency, Polymarket currently leads with a 103 ms p50 on its price endpoint over warm connections in the last 24h. But best depends on what you need: Polymarket has the deepest CLOB and a public WebSocket, Kalshi is the regulated US venue with a documented API contract, Manifold explicitly welcomes bots, Limitless is a CLOB with no API documentation to speak of, and Myriad has the smallest API surface. This leaderboard gives you the one number none of their docs publish, real latency and uptime measured continuously from three regions.
Does Kalshi have a public API?
Yes. Kalshi exposes a public REST API for market data, including the single market endpoint we probe, without authentication. Trading and the WebSocket feed require an account and API credentials. It is also the only venue in this cohort with a documented request budget per access tier. Its measured latency and uptime are on this page; how it behaves under rising request rates is covered in the pm-rate-limits benchmark.
How do you measure Polymarket API status and outage history?
Every 5 seconds, from three regions, the harness requests the midpoint of a pinned liquid market over a warm connection and classifies the outcome (ok, timeout, 4xx, 5xx, network error). The health gauge derived from those outcomes feeds the 24h and 7d uptime panels, and the latency time series keeps the shape of past incidents: an outage shows up as a gap or a spike you can scroll back to. Failures caused by our own pin going stale, for example a market that resolved intraday, are classified probe_invalid and excluded from both uptime and latency.
Why is the Myriad API slower from Europe and Asia?
Geography. Myriad's origin is a single region Heroku deployment in US East, with no multi region presence and no order book or WebSocket endpoints. From eu-west and Singapore every request pays a transatlantic or transpacific round trip before the API does any work. Use the region selector to compare venues from your own region; from us-east, Myriad's API is much closer to the rest of the cohort.
Why do latency numbers exclude CDN cache hits?
Because a cache hit measures the distance to the nearest edge node, not the venue's API. Manifold serves its entire API behind a 5 second cache and Kalshi's market list sits on CloudFront, so a naive average would mostly rank CDN proximity. Every sample carries a cache flag read from the response headers, and the headline aggregates only non cached, successful requests. The number you see is what a client polling for fresh quotes actually experiences at the origin.
Does this benchmark cover throttling or data providers?
No, deliberately. What happens to each venue's API as request rates climb, including 429 onset and queueing behaviour, is its own benchmark, pm-rate-limits, which runs a careful daily ramp. And if you consume venue data through a provider such as Mobula or Codex rather than calling the venue directly, the relevant number is relay freshness, measured in pm-data-freshness. This page answers two narrower questions: which venue API is fastest at a polite request rate, and is it up right now.
Source code github.com/MobulaFi/mobula-monorepo/tree/main/miniapps/pm-rate-limits