September 9 is Testers’ Day a day to celebrate QA professionals around the world.
This special date is linked to September 9, 1947, when Grace Hopper’s team recorded the first actual computer bug (a moth stuck in a relay!). That’s why we honor testers today, the people who keep technology running smoothly.
Share Your Bug Story
To mark the day, let’s do something fun (and rewarding):
Share the most memorable bug you’ve ever found.
It can be funny, surprising, or a real “saved the day” moment.
Everyone who joins will be entered into a lucky draw.
3 winners will each receive a $15 gift card!
Example:
I once found a bug where the login button only worked if your username started with “Z.”
Join the celebration by posting your story below, and let’s give a shout-out to testers everywhere for keeping the tech world safe!
Notes
Notes:
The eligible period to receive both badges is only from 2025-09-08T17:00:00Z to 2025-09-15T16:59:00Z.
We will announce a list of eligible winners for this activity after 2025-09-20T16:59:00Z.
The Katalon Holiday E-card Maker is back for Testers’ Day!
Show your appreciation to the incredible testers and QA professionals in your life. Send them a thoughtful note and let them know how much their hard work means to you by going to the link below
Thank you to all testers for the important work you do every day to improve quality and reliability.
but the system kept rejecting it as invalid. after debugging, i discovered that there was actually a zero-width space (Unicode U+200B) hiding inside the string, between the username and the @
here’s a quick proof using javascript:
const e = "notjohndoe\u200B@gmail.com";
console.log(e, e.length);
for (let i = 0; i < e.length; i++) {
console.log(i, e[i], e.charCodeAt(i));
}
and the result clearly shows 8203 (U+200B), an invisible character that breaks email validation
this bug was interesting because users didn’t type it directly. it often came from copy–pasting emails from chat apps, documents, or mobile keyboards, which silently added hidden Unicode characters
Thank you for sharing with us, this is mind blowing
btw, to all @trust_level_1 out there, the Giveaway is still going, please share your story with us fellow testers here and have a chance to win $15 gift card
one time in a banking app I was testing the loan calculator and instead of numbers it started to show like random fortune texts, things like your future looks bright or happiness awaits where the monthly payment was supposed to be. at first I thought it was some kind of joke inside the app or like an easter egg but then i checked the api calls and saw the response was coming from a json file that had been used in dev to test the layout. the developer had used a mock from a fortune cookie api and forgot to replace it with the real backend endpoint. If this went live people would open the app to know how much they pay per month and get a prediction about their destiny instead. we fixed it before release but was one of the funniest bugs I ever saw
oh my God, that’s interesting, but I found that extremely funny to find out “my future looks bright” instead of how much my monthly repayment is, hahah
Couple of years ago, one of the leading multinational financial services company made a critical error in their cashback calculation involving decimal handling. Instead of crediting 1 unit as intended, customers were mistakenly credited with 100 units. Had this bug not been identified, it could have led to significant financial losses for the company and a severely negative customer experience
Share Your Bug Story
Example:
Join the celebration by posting your story below, and let’s give a shout-out to testers everywhere for keeping the tech world safe! 
Notes:
Keep an eye out for the next round of giveaways - and don’t hesitate to share your own Bug Tales in the forum. You might be our next spotlight!