About
I like the hard parts of billing and payments.
I'm Jahid Hiron, a software engineer with 6+ years of experience. I build the money side of a product: subscriptions that charge the right amount, upgrades and downgrades that prorate correctly, failed payments that recover on their own, and webhooks that keep working when nobody is watching. When finance asks about a charge, the answer should already be in our own records.
ChartVPS Technologies
Today I work on ServerIQ, a server monitoring platform that watches 1,200+ servers for 200+ teams. I built the agent that runs on each server and reports every minute, the TimescaleDB pipeline that stores those metrics, and alerting that reaches people by email, SMS, WhatsApp, Telegram, Slack, Discord, Teams, or webhooks. I also built its billing on Stripe: plans, upgrades, downgrades, cancellations, failed-payment recovery, and reconciliation logs, so every charge can be explained.
Udemy
I started teaching on Udemy in 2023. Three years later, more than 72,000 students have taken my 6 courses, with an average rating of 4.5. Teaching keeps me honest. If I can't explain a decision simply, I probably shouldn't have made it.
How I think
When I look at a billing system, I start with a few questions. What happens if the same webhook arrives twice? What if it never arrives? If a customer upgrades on the 30th and downgrades on the 2nd, does their invoice match what support will tell them? If a card fails at 3 a.m., do they lose access, and do they get it back the moment they pay? If finance asks why someone was charged $47.13, can we answer from our own records without opening the payment dashboard? Getting every one of those answers to yes is the job. I also leave behind tests that prove it, so nobody has to remember why it works.
What I'm going deeper on
Stripe is where I started, not where I want to stop. I'm working through the rest of the payments stack: how a card payment actually moves from issuer to acquirer to payout, PayPal and local gateways like SSLCommerz and bKash, a gateway-agnostic billing engine with its own payment state machine, idempotency and a double-entry ledger, and the operations side: reconciliation, disputes, tax, and revenue recognition. I write up what I learn here as I go.
What I do now
I build ServerIQ, I write about billing and payments on this blog, I teach on Udemy, and I help a few teams each year get their billing and payment integrations right.