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Product engineer

I build booking and payment systems that are mission critical.

For web and mobile, where one mistake costs real money.

Mehedi Hasan Sarkar
5+years
Building web and mobile products, since 2021.
4products
With Stripe payments, and 5 side projects of my own.
3countries
Clients in Australia, Sweden and the UK.
100K+downloads
On Google Play, for a booking app I worked on.

How I work

Before I build it, I write down how it breaks.

Went wrongTwo people book the same slot at the same moment.

HandledThe server decides. The second booking is refused.

Went wrongA payment event arrives twice.

HandledRepeat deliveries of the same event are ignored, so the customer is charged once.

Went wrongA customer cancels before the booking time.

HandledThe card was only held, so the hold is released instead of refunded.

Went wrongA background job stops halfway.

HandledA reminder is marked as sent only after the provider accepts it.

Let's work together

Tell me what is breaking or what you need built. I will reply with how I would approach it.

Let's talk