diff --git a/src/config/env.test.ts b/src/config/env.test.ts
index de822d6e..6087101c 100644
--- a/src/config/env.test.ts
+++ b/src/config/env.test.ts
@@ -10,6 +10,37 @@ const baseEnv = {
   METRICS_API_KEY: "test-metrics-key",
 };
 
+describe("production secret strength", () => {
+  it("rejects weak and placeholder secrets in production", () => {
+    const result = envSchema.safeParse({
+      ...baseEnv,
+      NODE_ENV: "production",
+      SOROBAN_BILLING_CONTRACT_ID: "contract",
+      UPSTREAM_HOST_ALLOWLIST: "api.example.com",
+    });
+    expect(result.success).toBe(false);
+    if (!result.success) {
+      expect(result.error.issues.filter((issue) =>
+        ["JWT_SECRET", "ADMIN_API_KEY", "METRICS_API_KEY"].includes(String(issue.path[0])),
+      )).toHaveLength(3);
+    }
+  });
+
+  it("accepts 32-byte production secrets", () => {
+    const secret = "a".repeat(32);
+    const result = envSchema.safeParse({
+      ...baseEnv,
+      JWT_SECRET: secret,
+      ADMIN_API_KEY: "b".repeat(32),
+      METRICS_API_KEY: "c".repeat(32),
+      NODE_ENV: "production",
+      SOROBAN_BILLING_CONTRACT_ID: "contract",
+      UPSTREAM_HOST_ALLOWLIST: "api.example.com",
+    });
+    expect(result.success).toBe(true);
+  });
+});
+
 describe("env schema — Soroban billing", () => {
   it("requires a nonempty contract ID in production", () => {
     for (const contractId of [undefined, "", "   "]) {
@@ -30,6 +61,9 @@ describe("env schema — Soroban billing", () => {
   it("accepts a valid production billing configuration", () => {
     const result = envSchema.safeParse({
       ...baseEnv,
+      JWT_SECRET: "j".repeat(32),
+      ADMIN_API_KEY: "a".repeat(32),
+      METRICS_API_KEY: "m".repeat(32),
       NODE_ENV: "production",
       SOROBAN_BILLING_CONTRACT_ID: "contract_123",
       SOROBAN_BILLING_RPC_URL: "https://soroban.example.com",
diff --git a/src/config/env.ts b/src/config/env.ts
index 95523758..6e57da2e 100644
--- a/src/config/env.ts
+++ b/src/config/env.ts
@@ -543,6 +543,30 @@ export const envSchema = z
       .default(345_600_000), // 96h = 4 days, the slow-burn window
   })
   .superRefine((values, ctx) => {
+    const secretFields = [
+      ["JWT_SECRET", values.JWT_SECRET, "JWT_SECRET"],
+      ["ADMIN_API_KEY", values.ADMIN_API_KEY, "ADMIN_API_KEY"],
+      ["METRICS_API_KEY", values.METRICS_API_KEY, "METRICS_API_KEY"],
+    ] as const;
+    const placeholders = new Set([
+      "your-jwt-secret-here",
+      "your-admin-api-key-here",
+      "your-metrics-api-key-here",
+    ]);
+    for (const [path, value, name] of secretFields) {
+      const weak = new TextEncoder().encode(value).length < 32;
+      const placeholder = placeholders.has(value.trim().toLowerCase());
+      if (values.NODE_ENV === "production" && (weak || placeholder)) {
+        ctx.addIssue({
+          code: z.ZodIssueCode.custom,
+          path: [path],
+          message: `${name} must contain at least 32 bytes of entropy and must not use a placeholder value in production`,
+        });
+      } else if (values.NODE_ENV === "development" && (weak || placeholder)) {
+        console.warn(`${name} is weak or uses a placeholder; use a random value of at least 32 bytes before production`);
+      }
+    }
+
     if (values.NODE_ENV === "production" && !values.SOROBAN_BILLING_CONTRACT_ID) {
       ctx.addIssue({
         code: z.ZodIssueCode.custom,