hexcursion — the trip from an idea to something in production.
Consider me your next technology partner — not just another pair of hands.
6+
Years shipping
25+
Mobile apps delivered
30+
Web platforms
12M+
Users on platforms
To build technology that makes human life easier — software that feels obvious to use and quietly removes friction from an ordinary day.
I'm Mahmudul Islam, a Lead Software Engineer. 6+ years, 25+ mobile apps and 30+ web platforms across fintech, mental health, edtech and commerce — as a CTO, as a VP of Engineering, and as an engineer still in the codebase at midnight.
What I look for in a problem is leverage: a remittance app that gets a month's wages home in seconds, a therapy platform that reaches someone at 2 a.m., a storefront that puts a small merchant online in ten seconds. The stack is only ever a means to that. I want to lead teams and ship systems where the measure of success is a life made a little lighter — and to keep learning, mentoring and building for the long term while doing it.
Moving between the architecture diagram and the codebase — leading teams while writing the hard parts myself.
Mar 2026 — Present
Mangosteen Studio
Building community-focused AI products across the studio's ecosystem — CrushQuota AI, InvoiceAgent, Greenfield — end to end, from service architecture to the frontends people actually use.
Jul 2025 — Feb 2026
Relaxy
Owned engineering for a mental-health platform: team, system design, R&D and core delivery. Shipped Riri, the AI companion, and the therapy-session stack behind it.
May 2021 — Apr 2025
Zatiq
Four years building the commerce and fintech ecosystem: architecture, hiring, review culture, and the Zatiq Easy SaaS that put thousands of merchants online.
Feb 2021 — Jan 2024
Vivacom · Nairobi (remote)
Seven projects, 12+ applications maintained — MyCash, Hidmona and GetBetal among them. Money movement, compliance, and the reliability that comes with both.
Aug 2020 — Aug 2023
Prottoy Visual Learning
Took an edtech idea to a live platform: streaming, exams, content management and the whole technical resource plan behind it.
May 2020 — May 2021
EasyTrax
Complex tracking UI from designer specs, and the professional email template system for client communication.
I pick technology against business goals, not trends — then take ownership of the result.
Practical written lessons, clear examples, and projects that take you from the first idea to working software.
Learn Python one small idea at a time, from your first line of code to a tested, packaged production project.
Explore course →
Speak English with confidence through short lessons and real conversations, with audio for every sentence.
Visit english.hexcursion.com ↗Platforms I architected, led or built end to end — live products with real users and real money moving through them, plus what is shipping next.
Sr. Full Stack Engineer · Mangosteen Studio
Connect Gmail in two minutes and it reads only the billing mail — receipts, invoices, renewals — to show every subscription, token invoice and forgotten trial you are actually paying for. Read-only by design: it never sends, modifies or cancels anything.
Sr. Full Stack Engineer · Mangosteen Studio
Built for the breakup you can't bring up anymore, the grief that doesn't fit a mood tracker, the thought you replay at 2am. You choose what you're carrying, Rescript asks one question and then waits. Not a chatbot — and the entries stay yours. Web, iOS and Android.
Sr. Full Stack Engineer · Mangosteen Studio
Specialist agents investigate every account in a rep's book and an orchestrator turns what they find into ranked verdicts, priorities and next actions for the week — with the evidence kept visible so the call survives a territory review. Currently in early access.
Mobile App Developer
A Bitcoin research companion, not a wallet: live prices and candles, MACD and RSI overlays, government-holdings maps, curated news and a course library — with in-app purchases and an explainer chatbot.
CTO · Relaxy
Led engineering for a confidential wellness platform on iOS and Android: real-time chat, video sessions on Agora, mood journaling, nutrition and fitness guidance, and payments. 120,000+ families across Bangladesh, in three languages.
CTO · Relaxy
The web side of Relaxy: the front door for expert sessions and Riri, a business offering for employers, a Bangla and English content library, and the funnel that carries a visitor from a landing page into a booked session.
CTO · Relaxy
The companion inside Relaxy: it talks through a hard day, remembers earlier conversations, and suggests coping techniques drawn from the clinical team's own material, with emergency support one tap away. 50k+ active users and eight months of learning where retrieval helps and where it lies.
CTO · Relaxy
The booking side of Relaxy: browse verified psychologists and counsellors, match on what you're actually dealing with, pay, and meet in a private encrypted video room. 11,000+ sessions booked to date.
VP of Engineering · Zatiq
Architected a multi-tenant commerce platform for Bangladeshi merchants: storefronts in ten seconds, inventory and orders, bKash/Nagad/card payments, merchant and customer apps, custom domains. 100,000+ entrepreneurs on the platform and thousands of transactions a day.
Head of Technology · BDChat
Led the team building a communication platform for Bangladeshi expatriates: rich messaging, HD voice, video with screen sharing on the Agora SDK, plus remittance and bill payment in the same app.
CTO · Prottoy
An edtech platform closing the gap between urban and rural students: live and recorded classes, auto-graded exams, question banks, leaderboards, and a streaming pipeline that holds thousands of concurrent viewers.
Mobile App Developer · Amtel
Three apps — subscriber, agent, merchant — over one core-banking integration: transfers, cash in and out, bill pay and top-ups in real time, with role-based access, commissions and settlements, PIN and biometric locks.
Mobile App Developer · Hidmona
A remittance app moving money from Europe into Africa and Asia: live FX rates, KYC, multi-factor auth, fraud checks, transfer limits and end-to-end tracking — thousands of transactions a month across several banking rails.
Lead Full Stack Engineer · MyMaraneo, USA
A 365-day meal planner for iOS and Android: nutrition breakdowns, video recipes, imports from the web and social, Amazon Prime shopping, Stripe subscriptions with gifting, and a magazine section.
Software Developer · EasyTrax
Where it started: the UI and logic for Bangladesh's largest vehicle-tracking service — live maps with custom markers, geofence alerts, route history, fuel and driver-behaviour analytics, and the client email templates.
Field notes on mobile, frontend, backend architecture and leading engineers — written while the decisions were still fresh.
07 Oct 2026 · 16 min
Give an AI agent one real job and it becomes a team. Here is every piece of Google's Agent Development Kit that makes that work, each one run for real.
03 Oct 2026 · 15 min
We killed a real process in the middle of charging a card. With LangGraph's default setting the restart began from step one; with one flag it resumed at the charge. Either way, the charge ran twice. Here is the whole runtime: state, edges, reducers, checkpoints, interrupts, durability, parallel work, and what to ship.
30 Sep 2026 · 14 min
An agent is a model, your functions, and a loop. Here are the eight building blocks of a LangChain 1.x agent, every one run for real, plus the three numbers that decide whether it is safe in production: 5,000 calls, 109k tokens, and one spoofed user.
The trips, teams and milestones that recharge the builder — a few frames away from the keyboard.
“We appointed Mahmudul as Head of Technology for our fintech and communication platform. He showed strong technical leadership, clear architectural vision and effective team management — and delivered on time without compromising quality or security.”
“One of the most dedicated and capable engineers I've worked with. He breaks down complex problems, delivers clean scalable solutions, and mentors others while doing it — a measurable impact on both product quality and team morale.”
“Strong expertise across backend and frontend, understood the requirements quickly, and proposed solid technical solutions. Communication was smooth, deadlines were met, and the code quality was excellent.”
I take on a small number of engagements at a time — product builds, platform rescues, and engineering leadership. Tell me what you're shipping and when it needs to be live.