diff --git a/app/api/health/route.ts b/app/api/health/route.ts
new file mode 100644
index 0000000..ce1d107
--- /dev/null
+++ b/app/api/health/route.ts
@@ -0,0 +1,7 @@
+import { NextResponse } from "next/server";
+import { logLine } from "@/lib/logger";
+
+export async function GET() {
+  logLine("health.hit", { ok: true });
+  return NextResponse.json({ ok: true });
+}
diff --git a/app/api/signup/route.ts b/app/api/signup/route.ts
index 77b0678..af3a9ff 100644
--- a/app/api/signup/route.ts
+++ b/app/api/signup/route.ts
@@ -5,6 +5,8 @@ import { prisma } from "@/lib/prisma";
 import { DEFAULT_ALERTS, DEFAULT_DEFAULTS, DEFAULT_SHIFT } from "@/lib/settings";
 import { buildVerifyEmail, sendEmail } from "@/lib/email";
 import { getBaseUrl } from "@/lib/appUrl";
+import { logLine } from "@/lib/logger";
+
 
 function slugify(input: string) {
   const trimmed = input.trim().toLowerCase();
@@ -120,10 +122,16 @@ export async function POST(req: Request) {
       text: emailContent.text,
       html: emailContent.html,
     });
-  } catch {
+  } catch (err: any) {
     emailSent = false;
+    logLine("signup.verify_email.failed", {
+      email,
+      message: err?.message,
+      code: err?.code,
+      response: err?.response,
+      responseCode: err?.responseCode,
+    });
   }
-
   return NextResponse.json({
     ok: true,
     verificationRequired: true,
diff --git a/lib/email.ts b/lib/email.ts
index 1887acf..5695e87 100644
--- a/lib/email.ts
+++ b/lib/email.ts
@@ -1,4 +1,6 @@
 import nodemailer from "nodemailer";
+import { logLine } from "@/lib/logger";
+
 
 type EmailPayload = {
   to: string;
@@ -25,11 +27,23 @@ function getTransporter() {
     throw new Error("SMTP not configured");
   }
 
+  const smtpDebug = process.env.SMTP_DEBUG === "true";
+  logLine("smtp.config", {
+    host,
+    port,
+    secure,
+    user,
+    from: process.env.SMTP_FROM,
+    smtpDebug,
+  });
+
   cachedTransport = nodemailer.createTransport({
     host,
     port,
     secure,
     auth: { user, pass },
+    logger: smtpDebug,
+    debug: smtpDebug,
   });
 
   return cachedTransport;
@@ -40,15 +54,55 @@ export async function sendEmail(payload: EmailPayload) {
   if (!from) {
     throw new Error("SMTP_FROM not configured");
   }
-
-  const transporter = getTransporter();
-  return transporter.sendMail({
-    from,
+   logLine("email.send.start", {
     to: payload.to,
     subject: payload.subject,
-    text: payload.text,
-    html: payload.html,
+    from,
   });
+
+
+  const transporter = getTransporter();
+    try {
+    const info = await transporter.sendMail({
+      from,
+      to: payload.to,
+      subject: payload.subject,
+      text: payload.text,
+      html: payload.html,
+      headers: {
+        "X-Mailer": "MIS Control Tower",
+      },
+
+      replyTo: from,
+    });
+
+    // Nodemailer response details:
+    logLine("email.send.ok", {
+      to: payload.to,
+      from,
+      messageId: info.messageId,
+      response: info.response,
+      accepted: info.accepted,
+      rejected: info.rejected,
+      pending: (info as any).pending,
+    });
+
+    return info;
+  } catch (err: any) {
+    logLine("email.send.err", {
+      to: payload.to,
+      from,
+      name: err?.name,
+      message: err?.message,
+      code: err?.code,
+      command: err?.command,
+      response: err?.response,
+      responseCode: err?.responseCode,
+      stack: err?.stack,
+    });
+    throw err;
+  }
+  
 }
 
 export function buildVerifyEmail(params: { appName: string; verifyUrl: string }) {
diff --git a/lib/logger.ts b/lib/logger.ts
new file mode 100644
index 0000000..d24ba43
--- /dev/null
+++ b/lib/logger.ts
@@ -0,0 +1,20 @@
+import fs from "fs";
+import path from "path";
+
+const LOG_PATH = process.env.LOG_FILE || "/tmp/mis-control-tower.log";
+
+export function logLine(event: string, data: Record<string, any> = {}) {
+  const line = JSON.stringify({
+    ts: new Date().toISOString(),
+    event,
+    ...data,
+  });
+  console.log(line);
+  try {
+    fs.mkdirSync(path.dirname(LOG_PATH), { recursive: true });
+    fs.appendFileSync(LOG_PATH, line + "\n", { encoding: "utf8" });
+  } catch {
+    // If file logging fails, we still want something:
+    console.error("[logLine-failed]", line);
+  }
+}