SERVICE / API & SYSTEMS ARCHITECTURE
API Development & Backend Architecture from Sylhet, Bangladesh
A product is only as dependable as the systems behind it. I design and build APIs, backend services, and the infrastructure they run on — with clear service boundaries, predictable data flows, and the observability to debug problems quickly.
This is the work I do every day as Principal Systems Architect at Spacebly: owning the architecture decisions that let a platform grow without being rewritten. I bring the same discipline to client projects of any size.
What you get
REST APIs and backend services
Typed, documented APIs in Node.js/Express or Python/FastAPI with authentication, validation, rate limiting, and tests.
Systems architecture
Service boundaries, data models, and infrastructure plans for new platforms — or a structured review and refactor plan for an existing one.
Databases and data modeling
PostgreSQL and Supabase schema design, row-level security, migrations, and query performance tuning.
Edge and serverless
Cloudflare Workers and Supabase Edge Functions for low-latency APIs, rendering, and request routing.
Third-party integrations
Payment, accounting, authentication, and AI provider integrations built to survive API changes and outages.
Technology
Node.js, Express, TypeScript, Python, FastAPI, Flask, PostgreSQL, Supabase, Firebase, Cloudflare Workers, GitHub Actions.
Related projects
- Together CFO — built with Express (live site)
- Chohan Foundation — built with Express (live site)
- Medical Supplies DME — built with Vite, SSR (live site)
How it works
- Discovery call. A 30-minute call to understand the problem, constraints, and what success looks like.
- Scoped proposal. A written scope with milestones, timeline, and cost — fixed-price or hourly, whichever fits the work.
- Build in milestones. Working software delivered in small increments with regular demos, so you can steer early.
- Handover and support. Documentation, credentials, and a walkthrough — plus ongoing maintenance if you want it.
Frequently asked questions
Can you review or fix an existing backend?
Yes. A common engagement is an architecture and code review that ends with a prioritized list of fixes — performance bottlenecks, security gaps, and scaling risks — followed by implementing the most important ones.
Which backend technologies do you use?
Mostly Node.js with Express and TypeScript, and Python with FastAPI or Flask, on PostgreSQL or Supabase. For edge workloads I use Cloudflare Workers and Supabase Edge Functions.
Do you work with startups or only established companies?
Both. Startups usually need a pragmatic architecture that ships fast but will not collapse at scale; established teams usually need integrations, refactors, or a second senior opinion on a critical system.
Other services
Work with Saiki Sarkar
Have a web application, automation, or API project? See how engagements work, book a 30-minute call, or email ytosko@ytosko.dev.