StatusCurrently invite-only — finalizing onboarding
Hedera-nativeSmart contract events, delivered.

Real-time events for Hedera smart contracts.

Stop polling mirror nodes. HashStream delivers every smart contract event to your webhook the moment it reaches consensus — with retries, audit trails, and replay built in.

Log inSee how it works
P99 latency
< 8s
Uptime SLA
99.99%
Networks
2
POST /events
200 OK · 238ms
// Webhook delivered in 238ms · 200 OK
{
  "id": "evt_8f3a2b41",
  "event": "Transfer",
  "contractId": "0.0.48670965",
  "network": "mainnet",
  "consensusTimestamp": "1714545600.123456789",
  "data": {
    "from": "0.0.1234567",
    "to":   "0.0.7654321",
    "amount": "100000000"
  },
  "signature": "0xa1b2c3..."
}
Capabilities

Everything you need to ship.

Production-grade webhook infrastructure for the Hedera ecosystem. Built once, so you don't have to build it again.

  • 01

    Real-time delivery

    Webhooks fire within seconds of consensus. No polling, no missed events, no stale state.

  • 02

    Built-in resilience

    Exponential backoff, automatic retries, full audit trail per event. Replay any delivery on demand.

  • 03

    Predicate filtering

    Subscribe to a specific contract ID. Route events by network, status, or custom predicate.

  • 04

    Signed webhooks

    Every delivery is signed with ECDSA P-256. Verify it against our public JWKS so you know each request is genuinely from HashStream.

  • 05

    Mainnet & testnet

    Single dashboard, both networks. Switch with one click. Same API, same predictable shape.

  • 06

    Hedera-native

    Built specifically for Hedera. Deep expertise in HCS, mirror nodes, and the smart contract service.

How it works

Three steps. No polling.

  1. Step 01

    Register your contract

    Drop in your contract ID and pick a network. Mainnet or testnet, your call.

    Step 01json
    {
  "contractId": "0.0.48670965",
  "network": "mainnet"
}
  2. Step 02

    Wire your webhook

    Point a stream rule at your endpoint. Every delivery is signed — verify the signature against our public JWKS before you trust the payload.

    Step 02http
    // Headers on every delivery
x-hashstream-signature: <base64 ECDSA P-256>
x-hashstream-signature-timestamp: 1714545600123
x-hashstream-signature-key-id: <kid>
x-hashstream-signature-version: v1
  3. Step 03

    Receive events

    Sit back. Every matching contract event hits your endpoint with full payload, audit log, and replay tooling.

    Step 03json
    // Webhook delivered in 238ms · 200 OK
{
  "id": "evt_8f3a2b41",
  "event": "Transfer",
  "contractId": "0.0.48670965",
  "network": "mainnet",
  "consensusTimestamp": "1714545600.123456789",
  "data": {
    "from": "0.0.1234567",
    "to":   "0.0.7654321",
    "amount": "100000000"
  },
  "signature": "0xa1b2c3..."
}
FAQ

Common questions.

What is a smart contract event subscription?
A managed service that watches the blockchain for events emitted by contracts you care about, then delivers them to your endpoint as they happen — no polling required.
How is this better than polling a mirror node?
Polling is slow, expensive, and lossy. HashStream pushes events to you the moment they reach consensus, with retries and audit trails baked in.
Which networks do you support?
Hedera mainnet and testnet. We're Hedera-native by design and have no plans to fragment focus across other chains.
How is delivery secured?
TLS in transit, encrypted at rest. Every webhook is signed with an ECDSA P-256 (ES256) signature over the timestamp and raw body — verify it against our public JWKS to confirm the request came from HashStream and wasn't tampered with.

Ship faster. Stop polling.

Real-time webhook delivery for every contract event. Set up in minutes, runs forever.

Log inRead the docs