Tanvir AR

Founder

Nov 2025 - May 2026 • 6 mos

Designed and developed Langodium, an AI-powered language learning SaaS focused on live speaking practice, structured curriculum progression, and personalized learning. The platform enables learners to hold real-time conversations with an AI tutor, complete lessons and assessments, track progress across levels and units, receive adaptive placement recommendations, and manage credits, subscriptions, and account settings. Built the frontend with Next.js, React, TypeScript, and modern responsive UI patterns, including onboarding, placement testing, lesson progression, live session controls, transcript views, microphone and camera settings, subscription management, and interrupted-session recovery. Developed a NestJS backend with Supabase/PostgreSQL for authentication, curriculum data, learner progress, session records, transcripts, evaluations, billing, and administrative operations. Integrated AI voice and video services to support interactive speaking sessions and post-session performance analysis. Implemented a comprehensive Stripe billing system covering one-time purchases, subscriptions, renewals, plan changes, refunds, disputes, failed payments, dunning, credit holds, welcome credits, gift credits, and manual adjustments. Added safeguards for duplicate grants, frozen credits, disputed payments, webhook failures, and reconciliation between Stripe and internal records. Created an internal admin dashboard for managing users, orders, refunds, disputes, credits, emails, plan changes, billing health, and support workflows without direct database access. Strengthened production readiness through Supabase RLS, database privilege hardening, reliable webhooks, cron-based reconciliation, Cloudflare Queue processing, PostHog analytics, SEO, cookie consent, transactional emails, and deployments across Vercel, Railway, Cloudflare, Supabase, and Stripe. Key achievement: delivered a complete production-oriented AI SaaS covering product design, frontend, payments and so on.

Founder

Dec 2024 - Dec 2025 • 1 yr

Designed and developed Xspace, a production-oriented social networking and community platform combining elements of Reddit, X, and Facebook. The platform supports public discussions, community posts, short-form xposts, threaded comments, nested replies, follow relationships, primary and ghost profiles, notifications, moderation workflows, and real-time modmail. Built the frontend with Next.js, React, TypeScript, Redux Toolkit Query, and Tailwind CSS, delivering responsive dark and light interfaces, infinite feeds, profile and community pages, rich-text editors, media uploads, notification views, moderation consoles, and secure account flows. Developed a modular NestJS backend covering authentication, profiles, communities, posts, comments, voting, reporting, notifications, and moderation. Implemented Redis-backed feeds with pagination, engagement-based sorting, PostgreSQL fallback, stale-entry recovery, deletion filtering, and self-healing cache reconstruction. Integrated Cassandra for high-write voting and counter workloads. Created secure multi-profile identity switching between primary and ghost profiles, with ownership validation, privacy enforcement, and protection against cross-profile access. Built community moderation features including role-based permissions, moderator invitations, post approvals, reports, content removal and restoration, warning templates, activity logs, unread tracking, internal notes, and real-time modmail through Supabase Realtime. Strengthened production readiness through Supabase RLS, database views, indexes, migration hardening, runtime validation, API timeout handling, session propagation, analytics, image optimization, Cloudflare media storage, and deployment configuration for Vercel and Supabase. Key achievement: delivered the complete architecture across product design, frontend, backend, databases, caching, real-time systems, moderation, security, and operational tooling.