Mazedul Islam

eVisas.com is an online visa application platform. Admin staff builds one application form per destination country, and that form adapts to each applicant's nationality, visa type, entry type, processing speed, and earlier answers.

As the head of software engineering (contract), I set the architecture and technical direction and wrote most of the code for the back end, the admin portal, and the customer web app.

On the back end, I designed the PostgreSQL schema and built a NestJS API with Drizzle ORM and Zod covering form templates, conditional logic, visa packages and pricing, customer accounts with Google sign-in, document uploads to S3, saved drafts, and submissions.

I built the admin portal in React with TanStack Router and Query, including a drag-and-drop form builder and a visual rule editor for show/hide and required-field conditions.

I built the customer web app in Next.js, where applicants fill in the dynamic forms, upload passports and photos, save progress, and track their applications.

I also led the UI/UX designer and the React Native developer, and set up AWS staging with Terraform and GitHub Actions deployments.

PureSign is a web app that turns a photo of a handwritten signature into a clean, transparent PNG and lets people sign PDFs in the browser, with no account required. I built it alone, from product spec to production, including architecture, UI, back end, billing, and deployment.

Signature extraction and PDF signing run on the client side. Extraction uses adaptive thresholding to keep sharp edges and anti-aliasing. Signing renders pages with PDF.js and places signatures as overlays with pdf-lib, so the original text layers, fonts, bookmarks, and metadata stay intact.

The back end is Next.js on Netlify with PostgreSQL (Drizzle ORM and Neon) and Cloudflare R2 storage. I added email-code and Google sign-in with Better Auth, a saved-signature vault, and a usage dashboard. Subscriptions and pay-as-you-go credits run on Paddle, with signed, idempotent webhook handling.

Every API route enforces rate limits, daily export quotas, upload size caps, CSRF checks, and file-type sniffing. SEO was part of the build from day one, including metadata, schema.org markup, a sitemap, and guide pages.

Verbex is a multi-tenant AI voice agent platform that businesses use to handle automated inbound and outbound phone calls. As a full-stack engineer, I designed and built the platform's role-based access control from scratch and took it to production.

On the back end, I wrote a reactive Spring Boot service using WebFlux, R2DBC, PostgreSQL, and Redis that manages permissions, roles, and role assignments across organizations and workspaces, and resolves permission checks via URL pattern matching. I integrated it with the API gateway, extended the identity layer to support workspace-scoped API keys and organization membership, and wrote the database migrations and scripts to migrate existing customers to the new model.

On the front end, I built the matching Next.js/TypeScript console features, including role management, team invitations, workspace-scoped API keys, and a Do Not Disturb list with CSV bulk upload, backed by tenant-scoped APIs that validate phone numbers. I also maintained the Kubernetes/ArgoCD deployment configuration and API routing for these services.

Meteor Wallet is a non-custodial crypto wallet for the NEAR ecosystem, shipped as iOS and Android apps, a web app, and a Chrome extension, all built from a single React Native and TypeScript monorepo. I joined when the v2 rebuild started and contributed 1,000+ commits.

I built much of the shared component library in Tamagui, including buttons, inputs, tabs, toasts, skeleton loaders, and charts, and later the branded design system components used across every platform.

On the feature side, I built the token send flow, NEAR staking and unstaking with validator selection and reward claiming, NFT collections with NFT transfers, and wallet import via seed phrase and private key. I also built a multi-chain address book with contacts and recent addresses, the Meteor Card signup flow, and biometric and password app lock with auto sign-out. I added haptic feedback across the native app, interactive price charts for native and web, and fixed platform-specific UI issues on iOS, Android, and web.

I contributed to the back end of a hospital's mobile app, focusing on its queue management system. It notifies patients when their turn is ready and connects them with care staff by voice call.

The system is event-driven. I built the event producer and consumer that publish and handle queue events (arrived, acknowledged, canceled, and call events), with error handling in each handler so a single failure doesn't stall the pipeline.

On the serverless side, I built the notification pipeline for queue arrival and missed calls, including platform-specific push notifications and stored notification records. I also built the Twilio voice integration, including platform-specific token generation, call status callbacks, and voice messages in the patient's language. Notifications and voice messages support English, Thai, Japanese, and Arabic.

I documented the endpoints with OpenAPI/Swagger, fixed bugs such as a loop in the cancel/acknowledge notification, and wrote Jest unit tests for the event handlers and queue utilities.

SlimWiki is a SaaS wiki platform where teams create, organize, and share documentation, with real-time collaborative editing, public and private wikis, shareable links, custom branding, and subscription billing. I was a full-stack engineer on the product team.

On the back end, developed using Node.js/TypeScript, Koa, and PostgreSQL, I built a token-whitelist authentication layer backed by DynamoDB, covering token storage on login, signup, and social SSO, hashed tokens, TTL expiry, and revocation on logout. I also fixed Google SSO, tuned S3 signed URLs and asset caching, and moved logging and monitoring from Coralogix to Sentry.

On the front end, using Next.js, Tailwind, Radix UI, and Tiptap, I shipped:

• Revocable, shareable links
• Upgrade-plan flows for private wikis
• Logo upload handling
• Search and page-tree fixes
• Unit tests for auth components

I also contributed to the React/Redux client and the real-time editor proof of concept.

BRIKL is an eCommerce platform that lets merchants build and run branded online stores and micro-stores for custom and print-on-demand merchandise. I was a senior software engineer on the team, working in a large Nx monorepo (React, Next.js, TypeScript, and Apollo GraphQL) and shipping 46 merged pull requests over about 7 months across the merchant dashboard and the customer-facing storefront.

In the dashboard, I built a bulk product import flow, including an upload modal, file validation, live job status via GraphQL subscription, bulk order shipping and payment status updates, a tax-exemption settings tab for micro-stores, per-micro-store variant SKU overrides, role-based access controls, and custom checkout data in order details.

On the storefront, I fixed cart, checkout, coupon, tax display, and localization issues and added Markdown support to product and collection cards. I also contributed reusable components to the shared design system and wrote Jest and React Testing Library tests for new features.

An internal admin portal for managing the subscription and licensing side of a SaaS product, including organizations, plans, plan periods, products, and orders. I was the main contributor on both the front and back end.

On the back end, I built Java Spring Boot (JHipster) REST APIs using a PostgreSQL database, including plan and order management, rules for updating active orders, and a self-registration feature with generated access keys.

On the front end, I built the React and TypeScript UI with Material UI and Formik, including data tables, forms, tooltips, and loading states. I also fixed bugs, wrote tests, and polished the UX through to release.

A web-based file administration system for AtMetis, a Dutch risk management, inspection, and valuation firm, replacing manual Excel spreadsheets for tracking client files and field data. I worked as a full-stack developer on a two-person team, contributing to a responsive Angular (TypeScript and Angular Material) dashboard that engineers use on phones and tablets during site visits, and to the Spring Boot REST API with JPA/Hibernate and MySQL.

The system includes automatic file assignment to engineers based on workload, a state-machine workflow covering data collection, verification, and reporting, role-based access across departments, and automatic handoff of completed files to the company's risk management system.

A bulk import feature for AtMetis' file administration system, built for institutional clients who send requests covering dozens or hundreds of properties at once. I designed and built an Angular upload interface and a separate Python/Flask microservice that uses Pandas to parse, validate, and clean CSV data, keeping heavy preprocessing off the core Java back end.

The service integrates with the Spring Boot API, which stores the cleaned records in MySQL and automatically creates the files. This replaced manual, one-by-one data entry and cut intake time for large clients.

I designed and built an AI assistant for my portfolio that answers recruiter and client questions about my work, and rebuilt it twice as the requirements changed.

Version 1 was a full RAG pipeline, including pages scraped from my site and blog with Playwright, split into overlapping chunks, embedded with OpenAI text-embedding-3-small, and indexed in FAISS. Each question retrieved the top-6 chunks, which LangChain passed to a Llama 3.2 model I self-hosted with Ollama, streamed through an Express API (PM2, nginx).

Version 2 moved into Next.js. The knowledge base is only about 17 KB, so I replaced retrieval with cached full-context injection, which removed the vector store and retrieval misses. It refreshes through a CMS webhook, streams via the Vercel AI SDK, and has a guardrailed prompt and a lead-capture tool call. It also has Redis rate limiting, Zod validation, PostgreSQL logging, and PostHog failure tracking.