diff --git a/README.md b/README.md
index 1cc6d9b..755d8c6 100644
--- a/README.md
+++ b/README.md
@@ -45,6 +45,7 @@ const full = await aere.proof('0x' + sha256Hex);    // { block, txHash, finality
 // quantum readiness of a domain's public TLS edge (free, no key); attest:true notarizes the report digest on chain
 const scan = await aere.readiness('example.com');                    // { score, verdict, summary, findings, … }
 const attested = await aere.readiness('example.com', { attest: true }); // + attestation: { reportHash, txHash, proof, … }
+const fin = await aere.pqFinality('latest', 'testnet', 'both'); // AIP-21: { finality, agreement, postQuantumConfirmedByBoth, besu: {…}, nethermind: {…} }
 
 // pqVerify: pass interface:'external' to verify a standard FIPS 204/205 signature (the precompile implements the
 // internal interface; the gateway builds M' = 0x00 || len(ctx) || ctx || message for you)
diff --git a/index.mjs b/index.mjs
index 92280a7..f46284d 100644
--- a/index.mjs
+++ b/index.mjs
@@ -87,6 +87,13 @@ export class AereCloud {
   }
   readinessReport(domain) { return this._req('GET', `/pq/readiness/${encodeURIComponent(domain)}`, { auth: false }); }
 
+  // AIP-21 (2026-09-18): the per-block post-quantum finality record (seals heard by a validator, re-verified, quorum
+  // verdict). Free, no key. Testnet 28001 first; `network` is reserved for chain 2800 once the method reaches its validators.
+  // `client`: 'besu' (default), 'nethermind', or 'both' (two independent implementations, with `agreement` computed by the gateway).
+  pqFinality(block = 'latest', network = 'testnet', client = 'besu') {
+    return this._req('GET', `/pq/finality/${encodeURIComponent(block)}?network=${encodeURIComponent(network)}&client=${encodeURIComponent(client)}`, { auth: false });
+  }
+
   // audit log of every keyed request of this account for one UTC day (append-only, paged), with the day file's sha256
   auditLog({ day, offset = 0, limit = 1000 } = {}) {
     const q = new URLSearchParams({ offset: String(offset), limit: String(limit) });
diff --git a/package.json b/package.json
index aa4dd44..0fe451d 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@aere/cloud",
-  "version": "1.2.0",
+  "version": "1.2.1",
   "description": "Official client for the Aere Cloud API: keyed RPC, post-quantum verification, chain data, notarization, webhooks and gas sponsorship on Aere Network (chain 2800).",
   "type": "module",
   "main": "index.mjs",