How a Japan Trip Sparked the Idea Behind MailTrigger

Last summer, I was helping my family plan a trip to Okinawa, Japan. Like any good son/brother/uncle, I was in charge of finding flight tickets. And not just any tickets—we wanted the cheapest possible.

So I did what most people do: I set up flight alerts using sites like Skyscanner. Everything looked fine at first... until I realized something annoying:

These price alerts were only sent once a day.

Come on. Flight prices change constantly. Once-a-day emails? That wasn’t going to cut it. I needed real-time alerts, as soon as the price dropped.

The DIY Route (and the Headache That Came With It)

Being a bit of a nerd, I decided to build my own price tracker. I wrote a small Python script that checked flight prices every hour. When it saw a drop below my target price, it would send me a LINE notification.

At least, that was the plan.

Then I tried to actually send a LINE message using their API... and wow, that rabbit hole went deep. I had to deal with authentication tokens, weird message formats, headers, rate limits... it quickly turned into more work than I expected.

I just wanted to send a message. Why was this so complicated?

Enter MailTrigger: Email-In, Notification-Out

That’s when the lightbulb went off. What if I didn’t need to deal with LINE’s messy API at all?

Instead, I built a small service called MailTrigger. Here’s the idea:

• I send an email to a special address (through SMTP)
• MailTrigger reads the email
• Based on rules I set, it forwards that message to other platforms like LINE, Slack, or WhatsApp

It’s like an email-based trigger system. Super simple.

So I set up a rule: If I send an email with the subject "Flight Alert", MailTrigger will forward it to my LINE.

Done.

My Python script didn’t need to learn LINE’s API anymore. It just sent a plain email, and MailTrigger handled the rest.

The Result? Cheap Tickets and a New Tool

Thanks to the setup, I was notified immediately when prices dropped. I managed to grab tickets at the lowest price I’d seen in weeks. Mission accomplished.

But more importantly, this whole thing made me realize something:

There are tons of situations where people just want to trigger an action from a script, tool, or app—without dealing with complicated APIs.

And so, MailTrigger was born.

Why This Matters

MailTrigger makes it super easy to build notification workflows. You don’t need to learn the ins and outs of every messaging app. If your script can send an email, that’s all you need.

Real-time alerts. No API headaches. Just email it.

If you’ve ever written a script and thought, “I wish I could get a notification when this happens,” now you can.