Skip to content
mahadizulfiker
Mahadi Zulfiker
Open to work · Remote · GMT+6

Mahadi Zulfiker

full-stack software engineer in Dhaka, Bangladesh

I build voice-AI and commerce systems end-to-end: Bangla-speaking phone agents, wallet ledgers that have to balance, marketplaces that pay vendors correctly. Next.js, Node, PostgreSQL, React Native.

View work
years shipping
3
products shipped
22
built solo, end to end
10
result616 API operations behind Postgres row-level security, covered by 3,700+ unit tests and 700+ Playwright tests.Commerce ERP · sole author
scroll

Things I’ve built

Web app2026

Commerce ERP

DecisionIsolated tenants in the database itself: every tenant table has forced row-level security keyed to a per-transaction…
CostForced RLS makes every query and background job declare its tenant, and cross-tenant platform work needs a separate…

616 API operations behind Postgres row-level security, covered by 3,700+ unit tests and 700+ Playwright tests.

BunHonoDrizzle ORMPostgreSQL 17 (RLS)Redispg-boss
Sole authorPrivate repo
Architect and sole engineer, building through a spec-driven, test-first AI agent workflow.
Mobile app2025–2026

Talktivity

DecisionReplaced probabilistic parsing of the model’s report with deterministic scoring, and enforced per-plan voice-time…
CostDeterministic scoring is stricter and occasionally rejects a valid-but-oddly-shaped model response, so it needed a…

Cut a 32% incomplete-score rate on AI reports to near zero.

Next.jsReact NativeExpoNode/ExpressLiveKit / WebRTCGroq (STT/LLM)
Core contributorPrivate repo
Core contributor across web, mobile and backend; built the IELTS track end to end (team of ~6–8).
Web app2026

SeloraX Voice AI

DecisionBridged a SIP telephony gateway into a realtime LiveKit audio pipeline feeding Gemini Live, and paired it with a…
CostA custom TTS voice is far more work than a hosted one and has to be maintained, but no hosted option produced acceptable…
Gemini LiveLiveKitSIP gatewayCustom Bangla TTSNode.jsRealtime audio
Primary authorPrivate repo
Primary builder of the voice-AI engine.
Web app2026

XCall AI Assistant

DecisionBuilt the assistant on the app's own services rather than a parallel API, so anything it does is exactly what the page…
CostRouting through the product's real services means the assistant inherits every quirk of those services and has to be…

~30,000 lines of agent code, guarded by 1,300+ tests and a scored evaluation set.

Next.jsTypeScriptLLM tool callingGeminiMCP serverPrisma
Primary authorPrivate repo
Primary author of the assistant and its MCP layer: about 30,000 of 38,000 lines, on a team of five.
Web app2025–2026

Smart Sheba

DecisionSplit the system into customer, dashboard, super-admin, and control-plane services over one Postgres core, and modeled…
CostAn append-only ledger is more code and more careful queries than a single balance column, but it is the only version…

About 430 API paths, 130+ migrations and 5,800+ backend tests.

Next.jsNode.js / ExpressPostgreSQLPrismaRedisInngest
Sole authorPrivate repo
Sole author across backend, dashboard and storefront.
Website2026

NewTech Engineering

DecisionBuilt a Next.js front end over a Prisma/Postgres schema with an authenticated admin:
CostA full CMS is more up-front work than a static rebuild, but it removes the developer from every future content change,…
Next.js 16React 19TypeScriptPrisma / PostgreSQLNextAuthAWS S3 / R2
Primary authorPrivate repo

19 of 22 products were led or built solo.

Web app13Mobile app3Website2Package2Plugin1Game1
All work
under the hood

How the hard parts actually work

a call, end to endSeloraX Voice AI case study

A SIP gateway bridges a real phone call into a realtime LiveKit pipeline feeding Gemini Live, and the reply comes back through a custom Bangla voice. The accented path is the one the 300 ms latency budget lives on.

SeloraX Voice AI call pathA phone caller reaches a SIP gateway, which bridges into a realtime LiveKit room feeding Gemini Live. The reply is spoken by a custom Bangla text-to-speech voice and returned down the same call, the latency-critical path.CALLERinbound / outboundSIP GATEWAYtelephonyLIVEKITrealtime audioGEMINI LIVEreasoningBANGLA TTScustom voicespoken reply
call path · accent marks the latency-critical return

Client system, shown as an architecture narrative only: no source code, credentials, or user data.

Engineer who ships the whole thing

I’m Mahadi Zulfiker, a full-stack engineer with 3 years building production systems end-to-end: architecture, backend, interface, and deployment. Most of my work lives where things are hard to fake: realtime voice agents, wallet ledgers, multi-vendor marketplaces.

I like problems with a correctness cost, money that has to add up, a call that has to answer in Bangla under 300 ms, a score report that can’t silently fail. I’d rather write the stricter version that stays right than the quick one that drifts.

Comfortable owning a product solo, and comfortable being one of eight on a platform. I care about the details a reviewer actually notices, the empty state, the focus ring, the number that lines up.

Focus
Voice-AI · Commerce · Platforms
Now
Full-stack engineer @ SeloraX
Stack
Next.js · Node · PostgreSQL · RN
Based
Dhaka, Bangladesh (GMT+6)
Study
BSc CSE, Uttara University

Where I’ve worked

  1. Nov 2025 → PresentHybrid · Dhaka, Bangladesh

    Full-Stack Software Engineer

    SeloraX

    Building AI and commerce products end-to-end across the PERN/Next.js stack.

    • Built the SeloraX voice-AI call agent (realtime Bangla speech over SIP) and its self-serve platform: plans, prepaid billing, campaigns and a public API.
    • Primary author of the XCall AI assistant (~30k lines): an agent that runs calling campaigns from one chat, also served over MCP.
    • Sole author of Smart Sheba, a commerce and rewards platform with a ledger-backed wallet and rank engine.
    • Shipped SEO Studio and AI Marketing Studio; added the SEO/GEO layer and AI-consultation funnel on selorax.io.
    • Contributor to the core multi-tenant SaaS: backend, dashboard, and frontend.
    shipped thereand 7 more
  2. Jun 2025 → PresentRemote

    Full-Stack Engineer

    Talktivity

    Building a realtime voice-AI English tutor that scores spoken English and returns a CEFR report.

    • Core contributor across the React Native app, the Next.js web frontend (about a third of its code) and the Node backend (nearly 40% of commits).
    • Built the IELTS speaking and listening track end to end: mobile drills, web reports and the scoring APIs behind them.
    • Work across the realtime audio pipeline: LiveKit/WebRTC with Groq STT/LLM and Kokoro TTS.
    • Cut a 32% incomplete-score rate on AI reports to near zero by reworking the BullMQ scoring queue.
    shipped there
  3. Aug 2025 → Oct 2025Remote · Korea

    Full-Stack Engineer

    Anirix

    Built and optimized scalable full-stack features across backend services and UI.

    • Developed backend services and frontend improvements with modern frameworks.
    • Worked across a distributed, remote team.
    focus
    • Backend services
    • Frontend UI
    • Distributed remote team
  4. Jun 2025 → Jul 2025Dhaka, Bangladesh

    Frontend Engineer

    Softvence Agency

    Delivered responsive, client-ready interfaces with a focus on UI polish.

    • Built reusable component architecture and improved front-end performance.
    focus
    • Client-ready interfaces
    • Reusable components
    • Front-end performance
  5. Jan 2025 → Aug 2025Bangladesh

    Co-Founder & Full-Stack Engineer

    AMGoal

    Co-founded and built the product end-to-end.

    • Owned architecture, backend, frontend, and delivery.
    shipped there
before engineering
  • Data Annotator·Intelligent MachinesOct 2020 → Mar 2021
Education
  • BSc in Computer Science & Engineering (Honors)Ongoing
    Uttara University · 2024–2027
  • HSC & SSC
    Uttara High School & College · 2023

What I build with

Frontend
ReactNext.jsTypeScriptTailwind CSSReduxshadcn/uiReact Native
Backend
Node.jsExpressNestJSPythonRESTGraphQLPrisma
Data
PostgreSQLMongoDBMySQLRedis
Platform & DevOps
DockerVercelCI/CDAWS S3 / R2npm packagesGit
AI & Realtime
LiveKit / WebRTCGeminiGroqLLM integrationTTS/STT
Payments
StripeSSLCommerzAamarPayLemon SqueezyEPS

Let’s build something

Open to work

I’m Mahadi Zulfiker, open to full-time software engineering roles and select freelance work, from Dhaka, Bangladesh (GMT+6). If you’re hiring or have a system that needs building, the fastest way to reach me is email. I reply within a day.

mahade.adib45@gmail.com
WhatsApp · +880 1862 183566Download résumé
Based
Dhaka, Bangladesh · GMT+6
Open to
Full-time roles, select freelance
Reply
Within a day
Notice
Available to talk now
Chat on WhatsApp