diff --git a/identity-webhook/package-lock.json b/identity-webhook/package-lock.json
index 3f5c84d..5c17374 100644
--- a/identity-webhook/package-lock.json
+++ b/identity-webhook/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@pymthouse/clearinghouse-identity-webhook",
-  "version": "0.4.1",
+  "version": "0.4.2",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@pymthouse/clearinghouse-identity-webhook",
-      "version": "0.4.1",
+      "version": "0.4.2",
       "license": "MIT",
       "dependencies": {
         "jose": "^5.9.6"
diff --git a/identity-webhook/package.json b/identity-webhook/package.json
index ed6f53e..913e73d 100644
--- a/identity-webhook/package.json
+++ b/identity-webhook/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@pymthouse/clearinghouse-identity-webhook",
-  "version": "0.4.1",
+  "version": "0.4.2",
   "description": "API-key + OIDC identity webhook for go-livepeer remote signer (jose)",
   "type": "module",
   "license": "MIT",
diff --git a/identity-webhook/protocol.mjs b/identity-webhook/protocol.mjs
index 2131fcc..f13628b 100644
--- a/identity-webhook/protocol.mjs
+++ b/identity-webhook/protocol.mjs
@@ -28,6 +28,7 @@ export const REMOTE_SIGNER_HTTP_STATUS = {
   REFRESH_SESSION: 480,
   PRICE_EXCEEDED: 481,
   NO_TICKETS: 482,
+  /** Identity-hook: end-user allowance / credits exhausted (mint or live gate). */
   INSUFFICIENT_BALANCE: 483,
   BILLING_UNAVAILABLE: 503,
 };
@@ -114,11 +115,10 @@ export function authIdFromIdentity(identity) {
 
 export function isValidUsageIdentity(identity) {
   return Boolean(
-    identity &&
-      identity.issuer &&
-      identity.client_id &&
-      identity.usage_subject &&
-      identity.usage_subject_type,
+    identity?.issuer &&
+      identity?.client_id &&
+      identity?.usage_subject &&
+      identity?.usage_subject_type,
   );
 }
 
diff --git a/identity-webhook/verifiers.mjs b/identity-webhook/verifiers.mjs
index b0f9001..3864fe0 100644
--- a/identity-webhook/verifiers.mjs
+++ b/identity-webhook/verifiers.mjs
@@ -12,7 +12,12 @@
  */
 import { hkdfSync, randomBytes } from "node:crypto";
 import { createLocalJWKSet, createRemoteJWKSet, jwtVerify } from "jose";
-import { bearerToken, WebhookError } from "./protocol.mjs";
+import {
+  bearerToken,
+  REMOTE_SIGNER_ERROR_CODE,
+  REMOTE_SIGNER_HTTP_STATUS,
+  WebhookError,
+} from "./protocol.mjs";
 import { loadApiKeyStore } from "./keys.mjs";
 
 export const IDENTITY_AUTH_MODES = ["api_key", "oidc"];
@@ -117,10 +122,10 @@ export function createApiKeyVerifier({
   expiryTtlSeconds = 60,
 }) {
   if (!issuer) {
-    throw new Error("createApiKeyVerifier: issuer is required");
+    throw new TypeError("createApiKeyVerifier: issuer is required");
   }
   if (typeof resolveApiKey !== "function") {
-    throw new Error("createApiKeyVerifier: resolveApiKey is required");
+    throw new TypeError("createApiKeyVerifier: resolveApiKey is required");
   }
   return {
     kind: "api_key",
@@ -205,10 +210,55 @@ export async function discoverJwksUri(jwtIssuer, options = {}) {
  * When `fetchImpl` is set (tests / custom HTTP), JWKS is loaded through it into
  * a local keyset. Otherwise jose's createRemoteJWKSet fetches and caches.
  */
+async function createLocalJwksResolver(uri, fetchImpl) {
+  let response;
+  try {
+    response = await fetchImpl(uri);
+  } catch (err) {
+    throw new Error(
+      `JWKS request failed (${uri}): ${err instanceof Error ? err.message : err}`,
+    );
+  }
+  if (!response.ok) {
+    throw new Error(`JWKS request failed (${uri}): HTTP ${response.status}`);
+  }
+
+  let doc;
+  try {
+    doc = await response.json();
+  } catch {
+    throw new Error(`JWKS response is not JSON (${uri})`);
+  }
+  try {
+    return createLocalJWKSet(doc);
+  } catch (err) {
+    throw new Error(
+      `JWKS is invalid (${uri}): ${err instanceof Error ? err.message : err}`,
+    );
+  }
+}
+
+function createRemoteJwksResolver(uri) {
+  try {
+    return createRemoteJWKSet(new URL(uri));
+  } catch (err) {
+    throw new Error(
+      `JWKS URI is not a valid URL (${uri}): ${err instanceof Error ? err.message : err}`,
+    );
+  }
+}
+
+async function resolveOidcKeyResolver({ jwksUri, jwtIssuer, fetchImpl }) {
+  const uri = jwksUri ?? (await discoverJwksUri(jwtIssuer, { fetchImpl }));
+  return fetchImpl
+    ? createLocalJwksResolver(uri, fetchImpl)
+    : createRemoteJwksResolver(uri);
+}
+
 function createOidcKeyResolver({ jwks, jwksUri, jwtIssuer, fetchImpl }) {
   if (jwks) {
     if (typeof jwks !== "function") {
-      throw new Error(
+      throw new TypeError(
         "createOidcVerifier: jwks must be a jose key resolver function (e.g. createLocalJWKSet(...))",
       );
     }
@@ -219,44 +269,7 @@ function createOidcKeyResolver({ jwks, jwksUri, jwtIssuer, fetchImpl }) {
   let resolving;
   return async (protectedHeader, token) => {
     if (!remote) {
-      resolving ??= (async () => {
-        const uri = jwksUri ?? (await discoverJwksUri(jwtIssuer, { fetchImpl }));
-        if (fetchImpl) {
-          let response;
-          try {
-            response = await fetchImpl(uri);
-          } catch (err) {
-            throw new Error(
-              `JWKS request failed (${uri}): ${err instanceof Error ? err.message : err}`,
-            );
-          }
-          if (!response.ok) {
-            throw new Error(`JWKS request failed (${uri}): HTTP ${response.status}`);
-          }
-          let doc;
-          try {
-            doc = await response.json();
-          } catch {
-            throw new Error(`JWKS response is not JSON (${uri})`);
-          }
-          try {
-            return createLocalJWKSet(doc);
-          } catch (err) {
-            throw new Error(
-              `JWKS is invalid (${uri}): ${err instanceof Error ? err.message : err}`,
-            );
-          }
-        }
-        let jwksUrl;
-        try {
-          jwksUrl = new URL(uri);
-        } catch (err) {
-          throw new Error(
-            `JWKS URI is not a valid URL (${uri}): ${err instanceof Error ? err.message : err}`,
-          );
-        }
-        return createRemoteJWKSet(jwksUrl);
-      })();
+      resolving ??= resolveOidcKeyResolver({ jwksUri, jwtIssuer, fetchImpl });
       try {
         remote = await resolving;
       } catch (err) {
@@ -383,6 +396,57 @@ function createCompositeExchangeCache() {
   };
 }
 
+/**
+ * Map a non-OK composite token-exchange response to a webhook reject.
+ *
+ * go-livepeer `authLivePayment` forwards webhook body `status` + `reason` to the
+ * gateway unchanged (see remote_signer.go). Align allowance rejects with the
+ * live balance gate: 483 `insufficient_balance` / 503 `billing_unavailable`.
+ * Do not collapse payment failures to 401 (auth-only).
+ *
+ * Upstream mint gates often use HTTP 402 + `trial_credits_exhausted`; that is
+ * remapped onto the identity-hook wire statuses above.
+ */
+function webhookErrorFromExchangeReject(httpStatus, payload) {
+  const upstreamCode =
+    payload && typeof payload.error === "string" && payload.error.trim()
+      ? payload.error.trim()
+      : "";
+  const reason =
+    payload &&
+    typeof payload.error_description === "string" &&
+    payload.error_description.trim()
+      ? payload.error_description.trim()
+      : "";
+
+  if (
+    httpStatus === REMOTE_SIGNER_HTTP_STATUS.BILLING_UNAVAILABLE ||
+    upstreamCode === REMOTE_SIGNER_ERROR_CODE.BILLING_UNAVAILABLE
+  ) {
+    return new WebhookError(reason || "billing balance unavailable", {
+      status: REMOTE_SIGNER_HTTP_STATUS.BILLING_UNAVAILABLE,
+      code: REMOTE_SIGNER_ERROR_CODE.BILLING_UNAVAILABLE,
+    });
+  }
+
+  // Mint/OIDC exchange: HTTP 402 or trial_credits_exhausted → identity-hook 483.
+  if (
+    httpStatus === 402 ||
+    upstreamCode === "trial_credits_exhausted" ||
+    upstreamCode === REMOTE_SIGNER_ERROR_CODE.INSUFFICIENT_BALANCE
+  ) {
+    return new WebhookError(reason || "insufficient balance", {
+      status: REMOTE_SIGNER_HTTP_STATUS.INSUFFICIENT_BALANCE,
+      code: REMOTE_SIGNER_ERROR_CODE.INSUFFICIENT_BALANCE,
+    });
+  }
+
+  return new WebhookError(reason || "token exchange failed", {
+    status: 401,
+    code: "invalid_token",
+  });
+}
+
 async function exchangeCompositeApiKey({
   exchangeBaseUrl,
   publicClientId,
@@ -441,10 +505,7 @@ async function exchangeCompositeApiKey({
       `composite api key exchange rejected status=${response.status} client_id=${logSafe(publicClientId)} key_id=${keyId}` +
         (correlationId ? ` correlation_id=${correlationId}` : ""),
     );
-    throw new WebhookError("token exchange failed", {
-      status: 401,
-      code: "invalid_token",
-    });
+    throw webhookErrorFromExchangeReject(response.status, payload);
   }
 
   const accessToken =
diff --git a/identity-webhook/verifiers.test.mjs b/identity-webhook/verifiers.test.mjs
index 7552e83..c62f95e 100644
--- a/identity-webhook/verifiers.test.mjs
+++ b/identity-webhook/verifiers.test.mjs
@@ -657,7 +657,75 @@ describe("createOidcVerifier composite API key exchange", () => {
     });
     await assert.rejects(
       () => verifier.verify({ authorization: `Bearer ${clientId}_bad` }),
-      /token exchange failed/,
+      (err) => {
+        assert.equal(err.name, "WebhookError");
+        assert.equal(err.status, 401);
+        assert.equal(err.code, "invalid_token");
+        assert.match(err.message, /token exchange failed|invalid/);
+        return true;
+      },
+    );
+  });
+
+  it("maps exchange 402 trial_credits_exhausted to webhook 483", async () => {
+    const { jwks } = await setup();
+    const clientId = "app_3b386c81a1db1169fd2c3986";
+    const fetchImpl = async () =>
+      Response.json(
+        {
+          error: "trial_credits_exhausted",
+          error_description: "Starter allowance exhausted",
+          correlation_id: "c-402",
+        },
+        { status: 402 },
+      );
+    const verifier = createOidcVerifier({
+      jwtIssuer: "https://idp.test/",
+      jwtAudience: "clearinghouse",
+      jwks,
+      tokenExchangeBaseUrl: "https://billing.test",
+      fetchImpl,
+    });
+    await assert.rejects(
+      () => verifier.verify({ authorization: `Bearer ${clientId}_deadbeef` }),
+      (err) => {
+        assert.equal(err.name, "WebhookError");
+        // Match createBalanceGate / go-livepeer webhook passthrough wire.
+        assert.equal(err.status, 483);
+        assert.equal(err.code, "insufficient_balance");
+        assert.equal(err.message, "Starter allowance exhausted");
+        return true;
+      },
+    );
+  });
+
+  it("propagates exchange billing_unavailable as 503", async () => {
+    const { jwks } = await setup();
+    const clientId = "app_3b386c81a1db1169fd2c3986";
+    const fetchImpl = async () =>
+      Response.json(
+        {
+          error: "billing_unavailable",
+          error_description: "Billing allowance could not be confirmed",
+        },
+        { status: 402 },
+      );
+    const verifier = createOidcVerifier({
+      jwtIssuer: "https://idp.test/",
+      jwtAudience: "clearinghouse",
+      jwks,
+      tokenExchangeBaseUrl: "https://billing.test",
+      fetchImpl,
+    });
+    await assert.rejects(
+      () => verifier.verify({ authorization: `Bearer ${clientId}_deadbeef` }),
+      (err) => {
+        assert.equal(err.name, "WebhookError");
+        assert.equal(err.status, 503);
+        assert.equal(err.code, "billing_unavailable");
+        assert.equal(err.message, "Billing allowance could not be confirmed");
+        return true;
+      },
     );
   });
 });