• Add Spam Filtering to Your Nostr Client in 10 Lines
  • The API
  • Filter Spam
  • Detect Bots
  • Free Tier and SDK

§Add Spam Filtering to Your Nostr Client in 10 Lines

Every Nostr client has spam. Bots, impersonators, follow-farmers. If you’re building a client, you need trust scoring. But computing PageRank over 51K+ nodes and 620K edges isn’t something you want to do client-side.

§The API

The WoT Scoring API at wot.klabo.world crawls the follow graph every 6 hours, runs PageRank, publishes NIP-85 trust assertions, and exposes 49 endpoints.

The simplest integration — a trust score for any pubkey:

const res = await fetch(
  'https://wot.klabo.world/score?pubkey=' + hexPubkey
);
const data = await res.json();
// data.composite_score: 0-100 trust score
// data.followers: follower count

One call. The composite_score blends PageRank with external NIP-85 assertions (70% internal, 30% external).

§Filter Spam

Score every event author and hide low-trust accounts:

async function shouldShowEvent(event) {
  const res = await fetch(
    'https://wot.klabo.world/score?pubkey=' + event.pubkey
  );
  const data = await res.json();
  if (!data.found) return false;
  if (data.composite_score < 3) return false;
  return true;
}

§Detect Bots

The /sybil endpoint runs 8 behavioral signals:

const res = await fetch(
  'https://wot.klabo.world/sybil?pubkey=' + hexPubkey
);
const data = await res.json();
// data.classification: 'genuine', 'suspicious', 'likely_sybil'
// data.spam_probability: 0-100

§Free Tier and SDK

50 requests/day free. After that, L402 Lightning micropayments (1-10 sats).

JavaScript SDK: npm install nostr-wot

Full docs: wot.klabo.world/demo | wot.klabo.world/swagger