diff --git a/apps/api/src/config/proxy.ts b/apps/api/src/config/proxy.ts
index c520b50..ef6f086 100644
--- a/apps/api/src/config/proxy.ts
+++ b/apps/api/src/config/proxy.ts
@@ -6,7 +6,13 @@ export function resolveTrustProxy(raw = process.env['TRUST_PROXY']): TrustProxy
   const value = raw?.trim()
   if (!value || value.toLowerCase() === 'false') return false
   if (value.toLowerCase() === 'true') return true
-  if (/^\d+$/.test(value)) return Number(value)
+  if (/^\d+$/.test(value)) {
+    // Hop-count-only trust can't validate the immediate peer, so @fastify/proxy-addr
+    // no longer supports it (it always fails closed). The only documented deployment
+    // puts the reverse proxy on the same host, forwarding to loopback, so treat a
+    // numeric value as "trust the loopback interface" to keep TRUST_PROXY=1 working.
+    return ['127.0.0.1', '::1']
+  }
   const addresses = value.split(',').map((address) => address.trim()).filter(Boolean)
   if (addresses.length === 0) return false
   return addresses.length === 1 ? addresses[0]! : addresses
diff --git a/apps/api/test/rate-limit.test.ts b/apps/api/test/rate-limit.test.ts
index dde0dd6..f300762 100644
--- a/apps/api/test/rate-limit.test.ts
+++ b/apps/api/test/rate-limit.test.ts
@@ -35,7 +35,7 @@ describe('rate limit isolation and proxy handling', () => {
   it('parses explicit trust proxy settings safely', () => {
     assert.equal(resolveTrustProxy(''), false)
     assert.equal(resolveTrustProxy('false'), false)
-    assert.equal(resolveTrustProxy('1'), 1)
+    assert.deepEqual(resolveTrustProxy('1'), ['127.0.0.1', '::1'])
     assert.deepEqual(resolveTrustProxy('127.0.0.1, ::1'), ['127.0.0.1', '::1'])
   })