Built because the checkout was broken and nobody knew

Uptime monitors tell you the homepage answers. They say nothing about whether a new customer can sign up, get the welcome email, pay, and land in the paid area. That path breaks quietly: a changed selector, an email provider hiccup, a Stripe setting flipped in a deploy. You find out from a support ticket, days and a few customers late.

Mystra walks that path with a real browser after every deploy and proves each step. When something breaks, you get the screenshot, the request that failed and the console error, not a red dot. When Mystra cannot prove a break, it says “uncertain” and leaves you alone.

What it is, in one sentence

Mystra is revenue-path monitoring for web apps: a scripted Chrome browser that signs up on your product with a throwaway account, follows your welcome email, reaches Stripe Checkout without paying, and checks that the paid area is closed to an account that has not paid, after every deploy and on a schedule in between. The full mechanics are in How a run works.

Who makes it

Mystra is independent and self-funded, built in Europe. There is no funding round and no roadmap slide; there is a changelog that records every release. Support email is answered by the people who build the product, usually within a working day.

How it is built

The web app is Next.js on Vercel, with functions in Frankfurt. The runner is Playwright driving a real Chromium, so what it sees is what a customer sees, cookie banners and client-rendered forms included. Runs are queued in MongoDB Atlas. Every run gets its own address at inbox.mystra.run, received through Resend in the EU, so the welcome-email step waits on a real inbox rather than an API. Product analytics and error tracking go to PostHog in the EU, and never include evidence or email content. The full list of what Mystra touches on your app and what it stores is on the security page.

What Mystra checks on itself

A monitor that is down is worse than none, so Mystra checks its own plumbing every five minutes: the site, the database, the runner, the scheduler, and mail in and out. The results, with 90 days of history, are public on the status page. Incidents open and close on their own from those checks.

Principles

• Proof, not guesses. An alert without evidence is noise.
• Safe by default. Verified domains only, throwaway accounts, never pay unless you ask.
• Say what you know. Passed, broken, uncertain, or flaky, and why.
• Nothing to install. A deploy webhook in, an alert out. Removing Mystra is deleting the webhook.

Where it is going

Mystra is in public beta. The next pieces are payment-proof modes that finish Checkout for free with a 100%-off code, so the webhook path is proven too, and a wider set of signup shapes for the runner. Ideas and broken runs both go to contact.