Examples

Copy-paste Lit Action examples for triggers — echo a webhook payload, notarize it with a keyless signature — plus links to full runnable demos with contracts, setup, and end-to-end clients.

The actions below are complete: paste the code as a trigger’s action_code (see Creating Triggers). For flows that need a contract, a deploy step, and an off-chain client, see the full demos.

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1. Echo a webhook payload

The simplest trigger action — returns what it received. Useful to confirm a webhook is wired up and to see the exact params shape.

const main = async (params) => {
  return {
    ok: true,
    received_at: new Date().toISOString(),
    source: (params && params.source) || null,
    event: (params && params.event) || null,
    header_keys: params && params.headers ? Object.keys(params.headers) : [],
  };
};

Create it as a webhook trigger, then POST /webhook/<id> with any JSON body — the body comes back under event, and the safe request headers under header_keys.

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2. Notarize a payload with a keyless signature

Take any webhook payload, compute a deterministic digest, and sign it with the action’s own wallet — a key held by the Lit network, not by any server. The result is a tamper-evident receipt that only this exact action code could have produced. This is the building block the on-chain demos extend.

// Deterministic JSON (sorted keys, recursive) so any verifier reproduces
// the exact bytes that were signed.
const stableStringify = (v) => {
  if (Array.isArray(v)) return "[" + v.map(stableStringify).join(",") + "]";
  if (v && typeof v === "object") {
    return "{" + Object.keys(v).sort()
      .map((k) => JSON.stringify(k) + ":" + stableStringify(v[k]))
      .join(",") + "}";
  }
  return JSON.stringify(v);
};

const main = async (params) => {
  const payload = (params && params.event) || {};
  const digest = ethers.utils.id(stableStringify(payload)); // keccak256(utf8)

  const wallet = new ethers.Wallet(await Lit.Actions.getLitActionPrivateKey());
  const signature = await wallet.signMessage(ethers.utils.arrayify(digest));

  return { signer: wallet.address, digest, signature, payload };
};

Verify a receipt anywhere:

const recovered = ethers.utils.verifyMessage(ethers.utils.arrayify(digest), signature);
// recovered === signer  →  payload is authentic and unmodified

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3. Sign a scheduled heartbeat

A schedule trigger that signs a timestamped heartbeat each tick — a minimal “signed cron” you can post on-chain or to an external monitor.

const main = async (params) => {
  const wallet = new ethers.Wallet(await Lit.Actions.getLitActionPrivateKey());
  const message = `heartbeat ${params.scheduled_at}`;
  return {
    cron: params.cron,
    scheduled_at: params.scheduled_at,
    signer: wallet.address,
    signature: await wallet.signMessage(message),
  };
};

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4. React to a chain event

A chain-event trigger that reads ABI-decoded args from a matched log. Pair the Transfer(address,address,uint256) signature with an ERC-20 contract to watch transfers; decoded.arg2 is the amount.

const main = async (params) => {
  const e = params.event;
  return {
    chain: e.chain_key,
    tx: e.transaction_hash,
    from: e.decoded.arg0,
    to: e.decoded.arg1,
    amount: e.decoded.arg2,
  };
};

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Full demos

These need more than one file to run — a Solidity contract, a deploy script, an end-to-end client — and live under examples/lit-triggers/ in the repo:

Example	Trigger	What it shows
release-attestation	webhook	Verify a GitHub release webhook (HMAC over the raw body), then anchor the release on-chain via a keyless signer.
uptime-insurance	schedule	Parametric insurance: an autonomous ETH payout from a pool key nobody holds when a monitored service is down.
chainlink-feed-mirror	chain_event	Relay a Chainlink price feed to a chain Chainlink doesn’t support, with no trusted relayer.

Each ships a hardened action, a one-shot setup script (action CID, scoped key, contract deploy, trigger creation), and an end-to-end client.

Want an agent to wire any of these up for you? Point it at https://triggers.litprotocol.com/SKILL.md.