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WebSocketCrypto

Pyth Network Hermes (Price Update Service)

Pyth Network Hermes (Price Update Service) is a websocket from Pyth Network (Pyth Data Association) providing crypto data. Hermes is Pyth Network's price update service that aggregates the Pyth oracle's first-party publisher prices from Pythnet/Wormhole and serves them over a REST + server-sent-events (SSE) streaming API. A Polymarket bot can stream low-latency BTC-USD, ETH-USD and altcoin oracle prices to anticipate or settle "will BTC close above $X" hourly/daily markets, since Hermes delivers the same pull-oracle style price data on-chain settlement relies on.

At a glance

ProviderPyth Network (Pyth Data Association)
TypeWebSocket
CategoryCrypto
Real-timeYes — streaming
AuthAPI key
PricingFree public endpoint (10s updates, view-only/rate-limited); paid plans from $500/mo (Starter) and Pro from $2,500/mo for sub-second/1ms updates and API access — Free: every asset at 10s update frequency, view-only access (public Hermes endpoint hermes.pyth.network, 10 req/10s per IP), Starter: $500/mo — crypto, NAV, crypto indices/redemption rates at up to 1s updates with API access, Pro: from $2,500/mo (up to $10,000/mo full coverage) — all asset classes at real-time, up to 1ms update frequency, Note: Pyth Core upgrade July 31, 2026 requires an API key (Bearer token) for all users

What data it provides

  • BTC-USD, ETH-USD and altcoin spot price feeds (aggregated first-party oracle prices)
  • Per-feed price, confidence interval, exponent, and publish timestamp
  • Latest price updates via REST (/v2/updates/price/latest) and continuous SSE streaming
  • 3,000+ feeds across crypto, equities, FX, commodities/metals, rates and economic indicators
  • Signed price-update payloads (Wormhole VAAs) usable for on-chain settlement/verification
  • Beta endpoint (hermes-beta.pyth.network) for Aptos/Sui/Near testnets

Features

  • Server-sent-events (SSE) streaming plus on-demand REST fetch
  • Public endpoint rate limit: 10 requests per 10 seconds per IP (429 on overage)
  • Update cadence tiered: 10s (free) up to 1ms (Pro)
  • Official @pythnetwork/hermes-client TypeScript/JS SDK (HermesClient)
  • Open-source service; redundant third-party RPC providers (Triton, P2P, extrnode, Liquify) for production
  • First-party pull-oracle data matching on-chain settlement; signed updates verifiable on-chain

Links

Use it in a bot

Other crypto data sources

Listed, not endorsed. Pricing and capabilities change without notice — check the provider's own documentation before you depend on anything here. Browse the full data resources directory or the strategy database.
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