Best Polymarket Live Data

The ranking rewards whoever does the specific job best, not whoever has the most features. The full matrix that underpins it covers 10 providers across historical prices, historical L2, resolution, free tiers, and bulk export. Facts below were verified against public pricing and docs pages on September 24, 2026, and recorded in our provider matrix.

• 1. Official Polymarket APIs — for live state: GET /book for current depth, streaming updates, and discovery are the authoritative free source.
• 2. DepthFeed — for consolidated event-driven live depth across Polymarket, Kalshi, and Limitless with WebSocket plus REST history on paid plans.
• 3. PolyOrderbooks — for the records an archive starts with: 250ms captures become queryable history the moment they are written, so live research never waits for a backfill.
• 4. Predexon — for multi-venue live feeds plus wallet intelligence on paid tiers.
• 5. Telonex — for event-driven book snapshot channels suited to always-on research pipelines.
• 6. PolymarketData — for live-ish REST polling across a very broad market set at its documented cadence.
• 7. PolyTest — for live snapshot capture feeding its own backtest model as markets tick.

Measured coverage is the part a marketing page cannot answer. Our archive captures order books every 250ms and serves every plan, including free Starter, at that same 250ms query resolution. Competitors in the matrix cap documented L2 detail at 1-minute (PolymarketData), at 8 levels per snapshot (PolyTest), or rely on self-reported sub-second claims that conflict across their own pages (PolyTest, PolyBackTest). Resolution is not the only axis. Read the matrix row for interval-sampled versus event-driven capture (Telonex, DepthFeed), for on-chain-only limits that exclude the off-chain book entirely (Dune), and for archives that stop at coverage end or endpoint shutdown (polyReplay, Dome). Each listed product is the best answer for a specific job, and none is the best answer for every job.

Free tiers matter when the honest answer is the official API — which it usually is for live prices. Every provider in the matrix lists its free tier; where the free tier is only a sample or a trial, the row says so. If the job is historical depth, expect to pay for it, because depth history is the expensive thing to keep.

Live data on this venue is judged on three properties: seconds of latency, snapshot-to-stream merge quality, and whether the stream keeps the executable floor distinct from the mid. The last one is the silent differentiator because a floor-quoting feed survives reprises that a mid-quoting feed paints over.

The test that catches all three is a repricing hour: subscribe across the empty-side second and confirm the stream delivers the ladder change in order, with side intact and the reference-aligned gap visible. A provider whose stream compresses that into a price tick has removed the exact information your strategy needs.

Reconnect behavior matters more than feature lists: after a drop, the stream must resynchronize to the archive snapshot on the second, not on the millisecond of reboot, or your backfill has a hole where the reprise happened.

Live providers are really replay providers in disguise: the value of a stream is measured the moment a connection drops, resynchronizes, and the backfill must join the archive on the exact UTC second. Test that join once and the verdict is nearly free.

Subscribe through a genuine reprice window on trial; the steady-state demo always passes, and the event hour is where feeds separate.

Verify the merge against an archived snapshot for the same second; a mismatch in that join breaks every downstream panel.

Keep the archived snapshot endpoint as the fallback even while live, so a dropped reconnect never leaves an un-auditable hole.

• Full provider matrix
• Order book data
• Price history
• Data download