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I Build Full-Stack
Products That Ship.

Production web apps, SaaS platforms, and APIs — built end-to-end. React and Next.js on the front, Python and FastAPI on the back. One engineer, full ownership, shipped in weeks not months. No agencies, no handoffs.

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Vapi Groq Claude API n8n Make.com FastAPI Next.js 14 Python WebRTC Supabase Stripe Playwright Vapi Groq Claude API n8n Make.com FastAPI Next.js 14 Python WebRTC Supabase Stripe Playwright
€2k+
Hardware Replaced per Riedel Unit
6wk
Idea → Live SaaS (typical)
20+
Production Projects Shipped
6
Countries · Germany · USA · UK · UAE · Canada · India
01 — About

The Engineer
Behind the Systems

Suvon Roy — Full-Stack Developer, Dhaka
📍 Dhaka, Bangladesh
Working US/EU hours · Remote-first

I'm Suvon Roy — a full-stack developer. I don't build prototypes that crash on Tuesday. I ship production web apps, SaaS platforms, and APIs that handle edge cases, recover from failures, and deliver value every single day.

The unusual thing about how I work: I handle the entire stack end-to-end. React/Next.js frontends, Python/FastAPI and Node backends, Postgres data models, payment flows, auth, deployments — plus AI integrations and automations when they make sense. One engineer, no agency markup, no handoff delays. For most clients, this means I can ship in weeks what a team of three would take months to coordinate.

My most technically demanding project: a headless WebRTC intercom client running on a Raspberry Pi for a German broadcast facility on Riedel's STAGE™ platform. I reverse-engineered the protocol from browser traffic and replaced a €2,000 hardware unit with a single-command Pi install. It's been running in their live production environment without intervention.

When I build a SaaS, I measure time-to-first-paying-customer. When I build an API, I track p95 latency and error budgets. When I automate a workflow, I measure the hours saved. Every engagement starts with a clear business outcome — not a feature list.

Best At
Full-Stack SaaS · APIs · Web Apps
Stack
React · Next.js · Python · FastAPI
Response Time
Under 12 hours
Availability
Open · Q3 contracts
02 — Skills

Technical
Expertise

Frontend Development
React Next.js 14 TypeScript Vite Tailwind CSS shadcn/ui Framer Motion Responsive UI
Backend & APIs
Python FastAPI Flask Django Node.js REST API Design WebSockets WebRTC / SFU
Databases & Auth
PostgreSQL Supabase Redis MongoDB JWT / OAuth Stripe Multi-tenancy
AI & Automation
Claude API OpenAI Groq API Vapi Voice AI RAG Pipelines LangChain n8n Make.com Playwright Scrapy
Infrastructure & DevOps
Docker Linux / systemd Vercel Railway · Render GitHub Actions Raspberry Pi / ARM64
03 — Services

Packages &
Pricing

Productized engagements. Fixed scope, fixed price, fixed delivery window. You know exactly what you're getting and when. Custom scope available on a call.

01
Custom SaaS Platform — MVP to Production
Multi-tenant SaaS built end-to-end. Next.js 14 frontend, FastAPI or Node backend, Postgres/Supabase, auth, Stripe billing, admin panel, rate limiting. From idea to live product in 4–6 weeks, ready for paying customers.
Next.js 14FastAPISupabaseFrom $8,5004–6 weeks
02
Web App / Dashboard Build
Production React/Next.js web apps with custom backends. Admin dashboards, internal tools, customer portals, marketplaces. Clean UI, real auth, role-based access, deployed and documented. Pixel-perfect from your design or built from scratch.
ReactNext.jsTailwindFrom $4,5002–4 weeks
03
REST API & Backend Engineering
Backend-only engagements: REST/GraphQL APIs, third-party integrations, payment flows, webhooks, data models, background jobs. FastAPI or Node, Postgres, monitoring, OpenAPI docs, deployed and tested. Plugs into your existing frontend.
FastAPINode.jsPostgreSQLFrom $3,5002–3 weeks
04
WebRTC & Real-Time Systems
Full-duplex audio/video, embedded browser clients, intercom integrations, and custom protocol work. The Riedel STAGE™ project lives here — if you need WebRTC done right on weird hardware, this is the package.
WebRTCNode.jsEmbeddedFrom $6,0003–4 weeks
05
AI Integration & Automation
Add AI to your existing product, or build automations from scratch. Voice agents (Vapi/Groq), chatbots with RAG, n8n/Make workflows, scraping pipelines. Whether it's saving 20 hrs/week or shipping a new AI feature, it gets wired into your stack cleanly.
Claude APIn8nVapiFrom $3,0001–3 weeks
06
Monthly Retainer — Ongoing Engineering
For clients who need continuous build & maintain across the stack. Priority support, 40 hours/month, weekly check-ins, and Slack access. Best for scaling companies that have outgrown freelance gigs.
Retainer40 hrs/moPriority Support$8,000/mo3-month min
04 — Work

Featured
Case Studies

Every demo below is live and tappable
Real running deployments — not mockups, not screenshots, not slides.
● Deployed 11 Projects
000 Client Work Live Site
NORTH/FORM — Premium Clothing Brand Website

Full brand website for NORTH/FORM, a premium clothing label. Built to communicate the brand's identity with precision — editorial layout, fluid animations, product showcasing, and a conversion-focused UX. Deployed on Vercel with a fast, responsive front-end that looks as sharp on mobile as it does on desktop.

HTML / CSS / JS Animations Responsive Design Brand UI Vercel
The Brief
NORTH/FORM needed a website that matched their brand positioning — clean, premium, and intentional. Fashion-brand sites live or die on first impressions; the goal was a front-end that felt editorial without sacrificing load speed or mobile experience.
What I Built
  • Premium editorial layout with strong typographic hierarchy and whitespace-first design
  • Smooth, performant animations and transitions that reinforce the brand's identity
  • Fully responsive — pixel-perfect across mobile, tablet, and desktop viewports
  • Optimised for fast load times — no heavy framework overhead, deploys instantly on Vercel
Outcome
  • Live brand presence that communicates premium positioning at a glance
  • Fluid animations enhance the browsing experience without affecting performance
  • Mobile-first layout — where the majority of fashion brand traffic lands
  • Deployed and live at annimation-omega.vercel.app
001 Client Work Live Site
Rays UTC Cleaning — Conversion-Focused Business Site

Full business website for a professional cleaning company. Built to convert visitors into booked clients — clear service tiers, trust-building sections, and a frictionless contact flow. Mobile-first static site, local SEO ready, production-deployed.

HTML / CSS / JS Responsive Design Lead Capture Local SEO
The Brief
Rays UTC Cleaning needed a professional online presence that could compete with larger competitors in local search — a site that communicated services clearly, built trust quickly, and made contact dead simple.
What I Built
  • Conversion-focused layout with service tiers, testimonials, visible CTA above fold
  • Mobile-first responsive design — 70%+ of local service traffic is mobile
  • Contact form wired to lead capture; no missed inquiries from after-hours visitors
  • Structured for local SEO — semantic HTML, meta tags, fast load times
Outcome
  • Live at raysutcleaning.nl — production site the client actively uses to acquire customers
  • [REPLACE: # of leads generated / conversion rate / page speed score]
  • No framework overhead — plain HTML/CSS/JS, loads in under [X]s on mobile
  • Client can update copy without touching code
002 Client · Germany Production
Riedel STAGE™ Headless Intercom — Replaced €2,000 Hardware

A German broadcast facility needed a Riedel intercom node without buying a physical €2k SmartPanel. I reverse-engineered the proprietary STAGE™ protocol and built a headless Node.js client running on a Raspberry Pi 4. Full Keycloak auth, SockJS signaling, WebRTC Opus audio, PulseAudio FIFO pipeline — deployed as a systemd service. Live in their production environment.

Node.js WebRTC / Opus Raspberry Pi ARM64 Keycloak OIDC PulseAudio SockJS / STOMP
The Problem
The Riedel STAGE™ Virtual SmartPanel only runs inside Chromium browsers. The client needed it on embedded ARM64 hardware with no monitor, no GUI, real microphone I/O from a HiFiBerry ADC Pro hat — and they didn't want to pay €2,000/unit for the official hardware.
What I Built
  • Reverse-engineered Riedel's SockJS/STOMP wire protocol from browser DevTools — no SDK, no documentation available
  • Keycloak OIDC token refresh loop holding sessions stable for 8+ hour production shifts
  • arecord → named FIFO → Chromium fake-device pipeline; solved a SIGPIPE watchdog bug that killed audio on Chromium reloads
  • Single-command Pi installer, ARM64 native addon build, systemd unit with auto-restart
Business Outcome
  • €2,000+ hardware cost eliminated per intercom unit
  • [REPLACE: estimated savings across X units deployed / annual savings]
  • Zero dropouts observed across multi-hour live production sessions
  • Replaced a project the client had been trying to solve for [REPLACE: X months]
003 Client Work Live Demo
KHANS Codes & Standards — 30-Second Lead Response Automation

KHANS's sales team was losing leads to slow follow-up. I built an n8n + Make.com automation that turns a form submission into a qualified, logged, and followed-up lead within 30 seconds — at any hour. Their sales person recovered 8–10 hours/week of manual data entry, and follow-up rate went from "whatever they remembered" to 100% of leads.

n8n Make.com CRM SMS Automation Email Sequences
The Problem
Sales person was copy-pasting form submissions into a spreadsheet, then sending follow-up emails one by one. Leads submitted on weekends or evenings often didn't get a reply until the next business day. Lost leads were going to faster competitors.
What I Built
  • n8n webhook catches form POST, parses lead, writes to CRM in correct pipeline stage
  • First SMS fires within ~15 seconds; 5-step email sequence over 3 days with conditional branching
  • Make.com sends instant Slack alert to sales person with full lead context
  • Zero changes to existing form — webhook-only integration, no code on their server
Business Outcome
  • Response time: 8+ hours → under 30 seconds
  • 8–10 hours/week recovered from manual data entry
  • [REPLACE: $X estimated additional revenue from faster follow-up / Y% increase in qualified lead conversion]
  • Running unattended since delivery — zero maintenance calls
004 Deployed Sales Tool
AI Voice Agent for Service Businesses — Roofing Demo

A working AI voice agent built as a tangible sales demo for service businesses. "Jordan" — a Vapi voice agent — answers inbound calls, qualifies leads, and books appointments. Groq-powered chat widget on the site, FastAPI backend logging every interaction. I used this to close 3 paid automation contracts on Fiverr/Upwork in [REPLACE: timeframe].

Vapi Groq FastAPI Voice Agent Railway
Why I Built It
Most SMB owners have heard "AI voice agent" but never seen one working on their actual phone line. I wanted a tangible demo I could show during sales calls — "here's your missed call answered, here's the lead logged, here's the appointment booked." Built in a week.
How It Works
  • Vapi voice agent picks up inbound calls, runs qualifying questions, schedules callback
  • Groq/LLaMA chat widget embedded on site, system-prompted for industry Q&A
  • FastAPI backend writes every conversation turn and lead contact to Supabase
  • Single Railway deployment — backend + frontend on one domain
Business Outcome
  • Closed 3 paid contracts directly from this demo — [REPLACE: $X total contract value]
  • Voice qualification: ~75 sec per call vs 4–6 min on human calls
  • Groq free tier kept inference cost at zero; total infra cost was Vapi per-minute billing only
  • Proved a working AI voice stack for an SMB is days of work, not months
005 SaaS Platform Live Demo
VoiceForge AI — Production TTS SaaS in 12 Days

A full ElevenLabs alternative built around Coqui XTTS v2. Three-tier billing (Free / Pro / Enterprise), Supabase auth, Upstash rate limiting, real-time audio streaming, Next.js 14 frontend. Shipped from idea to live product in ~12 days, running at ~$0/month on free tiers until real traffic justifies scaling.

FastAPI XTTS v2 Next.js 14 Supabase Stripe
The Starting Point
ElevenLabs charges $22+/month. XTTS v2 is open-source and produces similar quality on clean input. I wanted to prove I could wrap it in a real SaaS — auth, billing tiers, rate limiting, frontend — and ship the whole thing in under two weeks at zero infra cost.
Stack Decisions
  • FastAPI streaming endpoint — XTTS generates chunks, client receives audio as it renders
  • Supabase Auth with JWT; role stored in user metadata, checked on every API request
  • Upstash Redis for per-user sliding-window rate limiting, configurable per tier
  • Next.js 14 with RSC — most pages server-rendered, only audio player is client-side
  • Railway + Vercel + Supabase — all free tier, total monthly cost: ~$0
What This Proves
  • Full production SaaS shipped in ~12 days
  • Auth + billing wiring took longer than the XTTS integration itself
  • Rate limiting actually mattered — one user could exhaust free CPU in minutes without it
  • If you need a SaaS MVP fast, this is what's possible
006 Product · Gumroad Live
NEXUS AI — Monetized Windows Desktop Assistant

A JARVIS-style desktop assistant sold on Gumroad at $29/license. Wake-word detection, screen + clipboard awareness, multi-provider LLM support (Groq, Gemini, Claude, Ollama), packaged as a .exe with a FastAPI license validation backend. Proves I can build, package, and monetize a real product — not just deliver client work.

Python Multi-LLM Wake Word PyInstaller License System
What I Was Solving
Every AI tool lives in a browser tab. I wanted one that knows what process is eating my CPU, can read what I just copied, see what's on my screen, and respond when I say its name — no tab switching, no typing. And I wanted to sell it, not just build it.
Technical Decisions
  • Wake-word runs entirely local via Porcupine — no audio sent to cloud, activates in <100ms
  • LLM provider is swappable — Groq for speed, Ollama for offline, Claude/Gemini for quality
  • Screenshot + clipboard context injected into every prompt automatically
  • License validation backend so I can issue and revoke keys per Gumroad sale
What It Proves
  • Built, packaged, and monetized as a product — not a client deliverable
  • [REPLACE: total units sold / total revenue generated]
  • End-to-end ownership: code, packaging, distribution, billing, license revocation
  • Demonstrates I think about products, not just code
007 Automation Tool Open Source
USA Visa Booking Automation — TLS Fingerprint Evasion + reCAPTCHA Solver

A stealth automation client for a Portuguese government visa portal. Bypasses TLS fingerprinting, solves reCAPTCHA v2/v3 via CapMonster, rotates residential proxies, and auto-books appointment slots the moment they open. Designed to defeat bot-detection systems that block conventional Selenium/Playwright approaches.

Python TLS Fingerprinting CapMonster Proxy Rotation Playwright
The Problem
Government visa portals detect and block standard browser automation via TLS handshake fingerprinting, browser attribute leakage, and aggressive reCAPTCHA. Appointment slots vanish in seconds, making manual booking nearly impossible for users in high-demand queues.
What I Built
  • TLS fingerprint spoofing to mimic a real Chrome session at the TCP/SSL layer — invisible to Cloudflare-class bot detection
  • CapMonster integration solving reCAPTCHA v2 and v3 tokens on the fly with sub-5s turnaround
  • Residential proxy pool rotation per request, cycling IPs to evade rate-limit bans
  • Slot polling loop: checks availability every N seconds, auto-submits booking form on first open slot
Technical Depth
  • Bypasses TLS-based bot detection — no standard library exposes this level of control
  • Handles session token refresh to maintain authenticated state across long polling runs
  • Configurable retry logic, exponential back-off, and failure alerting
  • Pure Python — no headless browser overhead; fast and resource-light on VPS
008 Automation Tool Open Source
IRCTC Ticket Booking Automation — Indian Railways Fast-Track Bot

High-speed Python automation for the Indian Railways (IRCTC) ticketing portal. Detects seat availability in real-time, auto-fills passenger details, navigates the multi-step checkout flow, and completes payment before slots disappear — critical in a system where Tatkal quota sells out in under 60 seconds.

Python Selenium Automation CAPTCHA Bypass Session Handling
The Problem
IRCTC Tatkal and premium quota tickets open at a fixed time and sell out within 30–60 seconds during peak demand. Manual booking via browser is practically impossible for high-demand routes — the multi-step auth + form flow takes longer than the window stays open.
What I Built
  • Pre-authenticated session holding login state across polling windows — no re-login delay at booking time
  • Real-time seat availability polling with configurable class/quota/train filters
  • Auto-fill passenger details, berth preferences, and contact info in a single sweep
  • Payment flow navigation with CAPTCHA handling to complete checkout end-to-end
Engineering Notes
  • Sub-second form-fill using pre-staged data structures — no typing simulation delays
  • Handles IRCTC session timeouts and re-authentication transparently
  • Configurable alert system: Telegram/email notification on successful booking or failure
  • Demonstrates deep knowledge of session-gated, time-sensitive automation at scale
009 AI Data Tool Open Source
AI Mail Scraper — Gemini-Powered Email Extraction with GUI

A desktop email harvesting tool with an AI brain. SeleniumBase navigates and scrapes contact data from target sites; Gemini AI classifies and deduplicates results; a Tkinter GUI lets non-technical users configure targets, run scrapes, and export clean CSVs — no command line required.

Python SeleniumBase Gemini AI Tkinter GUI CSV Export
Why I Built It
Outbound sales teams waste hours manually hunting for contact emails across directories, LinkedIn, and company sites. Existing scraper tools dump noisy, duplicated data with no intelligence layer. I wanted a tool that scrapes, classifies, and delivers clean leads — wrapped in a UI a non-developer can actually use.
How It Works
  • SeleniumBase undetected-mode crawls target URLs, handling JS-rendered pages and basic bot protections
  • Gemini AI classifies extracted emails by role/department and filters out noreply/support noise
  • Deduplication pass removes cross-source duplicates before export
  • Tkinter GUI: set targets, run, monitor progress, one-click CSV export — zero terminal required
What This Shows
  • AI layer adds real signal — classified leads, not raw regex dumps
  • GUI wrapping a technical tool for non-developer end users — product thinking, not just engineering
  • SeleniumBase undetected mode handles sites that block Playwright/vanilla Selenium
  • Portable: ships as a standalone .exe via PyInstaller for Windows distribution
010 Fintech Tool Open Source
Trading Bot Pro — Automated Strategy Execution Engine

A Python-based algorithmic trading engine that executes configurable strategies against live market data. Supports multiple exchanges/brokers via unified API abstraction, real-time signal generation, position management, stop-loss/take-profit logic, and trade logging — running unattended 24/7.

Python Trading APIs Strategy Engine Real-Time Data Risk Management
What It Does
Trading Bot Pro connects to exchange APIs, processes live price feeds, and executes buy/sell orders based on configurable technical strategies — all without human intervention. Designed for reliability: it handles API downtime, reconnects automatically, and never leaves an open position unguarded.
Core Architecture
  • Unified exchange adapter layer — swap brokers by changing one config value
  • Signal engine: pluggable strategy modules (RSI, MA crossover, custom indicators)
  • Position manager: entry sizing, stop-loss, take-profit, and trailing stop enforcement
  • Trade log with full execution history, PnL tracking, and configurable alerting (Telegram/email)
Engineering Highlights
  • 24/7 unattended operation — reconnect logic, error recovery, systemd-compatible
  • Paper trading mode for strategy validation before going live with real capital
  • Modular strategy API — add a new signal source without touching core execution logic
  • Demonstrates real-time event-driven Python at the intersection of finance and automation
05 — Process

How We'll
Work Together

01
Discovery Call (20 min, free)
We jump on a call. You tell me the problem. I tell you honestly whether I can solve it, how long it'll take, and what it'll cost. No pitch deck. No sales theatre. If it's not a fit, I'll say so and point you somewhere better.
02
Scoped Proposal (48 hours)
Written proposal with fixed scope, fixed price, fixed timeline. Milestones, deliverables, and what's explicitly out of scope. You approve, sign, and pay 50% deposit. Or you don't — no pressure either way.
03
Build Sprint
I build in tight loops with regular demos. You see working software early and often — never a black box with a big reveal at the end. Slack access for fast questions, async updates so you don't waste time in meetings.
04
Handoff + 30-Day Support
Final delivery includes documentation, runbook, and a recorded walkthrough. 30 days of post-delivery support included — bug fixes, small tweaks, and "how do I…" questions. Optional retainer afterwards if you want ongoing engineering.
06 — Reviews

What Clients
Say

★★★★★

The AI workflow he built for our lead system was a game changer. Every lead now gets followed up within 30 seconds — automatically. Our team's time is freed up for actual closing.

A
Ahmad K.
Operations Director · KHANS C&S
Direct
★★★★★

Built an n8n workflow that saved our marketing team 20+ hours a week. Communication was extremely clear throughout. Delivery was ahead of schedule with excellent documentation.

S
Sarah K.
Marketing Manager · USA
Upwork
★★★★★

He solved a WebRTC problem in 48 hours that our in-house team had been struggling with for weeks. Deep technical knowledge, zero hand-holding needed, proactive about edge cases.

J
Jonas H.
CTO · Germany
Direct
★★★★★

Rare combination: technically exceptional AND a great communicator. He understood our requirements faster than any developer I've worked with and delivered a system that's been running flawlessly for months.

M
Michael R.
Founder · UAE
Direct
★★★★★

Our AI video pipeline in n8n goes from a brief text prompt to a finished video in under 10 minutes. It replaced two freelancers and an entire afternoon of manual work every single day.

L
Lisa W.
Content Director · Canada
Upwork
★★★★★

The web scraping framework extracts data from sites I thought were locked down. Clean code, great error handling, and he explained every technical decision. Will hire again.

T
Thomas B.
Data Analyst · UK
Fiverr
★★★★★

The AI workflow he built for our lead system was a game changer. Every lead now gets followed up within 30 seconds — automatically.

A
Ahmad K.
Operations Director · KHANS C&S
Direct
★★★★★

Built an n8n workflow that saved our marketing team 20+ hours a week. Communication was extremely clear throughout.

S
Sarah K.
Marketing Manager · USA
Upwork
07 — FAQ

Questions
Buyers Ask

Q1
How do I know you can actually deliver?
Every project linked above is a real, running deployment — tap "Live Demo" on any case study. You can test the voice agent. You can submit a fake lead to the KHANS demo. The Riedel client used my code in their production broadcast facility. Proof, not promises.
Q2
What if I'm not happy with the result?
Fixed-scope projects mean you know exactly what you're paying for before signing. 50% deposit, 50% on delivery. If I miss the scope, I fix it on my time. If I miss the deadline, the back-half payment adjusts. Risk lives with me, not you.
Q3
You're based in Bangladesh — how does timezone work?
I run on US/EU client hours. Standard turnaround on questions is under 12 hours. For active sprints, I block time that overlaps your morning. Slack/Discord access throughout the project — no waiting for "tomorrow."
Q4
Why hire one engineer instead of an agency?
No project manager markup. No handoff delays. No "the dev who built it left, here's a junior who'll figure it out." I write the code, I own the decisions, I'm responsible if it breaks. For projects under [REPLACE: $50k], a senior solo engineer ships faster and cleaner than a team.
Q5
Do you sign NDAs / do code stay private?
Yes to NDAs — happy to sign yours or use a standard one. All client code is private by default. The repos I show in case studies are demo/sanitized versions, never the actual client deliverable. IP transfers to you on final payment.
Q6
What's the fastest way to get started?
Book a 20-min discovery call. Within 48 hours of that call you'll have a written proposal with fixed scope, price, and timeline. If it's a fit, we start the same week.
08 — Writing

Technical
Articles

WebRTC · Embedded
Building a Headless WebRTC Intercom on Raspberry Pi: The Complete Guide

How I reverse-engineered a proprietary intercom protocol, solved Keycloak token refresh edge cases, and piped real microphone audio through PulseAudio FIFOs into a headless Chromium instance.

2025-04 Read Article →
SaaS · Infrastructure
The Zero-Cost AI SaaS Stack: Groq + Supabase + Railway + Vercel

A practical breakdown of how to build and deploy a production multi-tenant AI SaaS with user auth, rate limiting, and payment integration — running at $0/month on free-tier services until you hit real scale.

2025-03 Read Article →
n8n · Automation
n8n vs Make.com in 2025: A Production Developer's Honest Comparison

After building over 20 workflows across both platforms for real clients, here's what I've learned about when to use each one — including the edge cases, pricing gotchas, and hidden limitations nobody talks about.

2025-02 Read Article →
09 — Contact

Let's Build
Something

Ready to ship?

The fastest path is a 20-minute discovery call. You tell me the problem, I tell you honestly whether I can solve it and what it costs. No pitch, no pressure. If we're a fit, you have a written proposal within 48 hours.

📞 Book a 20-min Call

Prefer messages? Reach out directly:

Available for Q3 contracts — Responding within 12 hours
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