Backend systems, platform tooling, APIs
Hi, I'm Debashis Mitra,
software engineerfrom Kolkata, India
I design and implement solutions to problems in society into application systems based on website and mobile platforms.
What I Work On
Not a skills list. These are the responsibilities I take on.
Backend Systems
Designing and operating REST APIs with Spring Boot, applying DTO validation, security chains, OAuth2, and JWT. Building services that handle real traffic.
Distributed & Data
Event-driven architecture with Kafka, multi-database design (relational + document + cache), and systems that stay consistent under load.
Cloud & Operations
Deploying and operating services on Azure VMs with Docker, Nginx, SSL termination, secrets management, and uptime monitoring.
Developer Tooling
Building SDKs, CLI tools, and internal platforms that other developers rely on. Integration-first thinking means less friction and more reliability.
Upblit
Problem
Existing monitoring tools were either too expensive or too generic for small product teams. Upblit gives teams a lightweight, self-hosted way to track uptime, send alerts, and publish status pages.
What it does
Teams register services, configure check intervals, and get a public status page automatically. When something goes down, alerts fire; when it recovers, the incident is logged. The system is API-first.
Architecture
Engineering Challenges Solved
Tech Used
Other Systems I've Built
The flagship carries weight. These show consistency.
Automated customer-facing chatbot pipelines for businesses using retrieval-augmented generation over proprietary documents without vendor lock-in.
A LeetCode-like platform where users solve algorithmic problems, track personal progress, and review solution histories across sessions.
Practical Experience
Framed by what was delivered, not job titles.
Backend Engineer - Freelance
2024 - Present- Designed and delivered backend systems for client products from scratch
- Integrated transactional email infrastructure with SPF/DKIM and queue-backed delivery
- Deployed production APIs on cloud VMs with zero-downtime rollout strategy
- Built API key issuance and scoped access control for multi-tenant clients
- Set up monitoring and alerting for client-facing services
Engineering Notes
Writing proves understanding. Understanding reduces hiring risk.
Why my first caching strategy failed
I cached at the wrong layer. Data was stale in Redis while the DB had the truth, and that changed how I think about invalidation.
ReadDesigning token authentication for Upblit's API
A walkthrough of a dual-token system: short-lived JWTs for sessions and long-lived API keys for SDK consumers with scoped permissions.
ReadDeploying Spring Boot with Nginx and SSL on Azure
From a raw VM to production service: reverse proxy config, Let's Encrypt renewal, and a zero-downtime restart strategy.
ReadOpen Source & Community Work
Hacktoberfest Contributor & Maintainer
Reviewed pull requests, triaged issues, mentored first-time contributors, and kept community submissions production-minded.
Community Building
Grew a project to 11k users organically with contributor onboarding, clear guidelines, and steady issue triage.
Issues & Code Review
Resolved 60+ issues and reviewed public patches while maintaining backward compatibility across a public API.
Technical Stack
Tools do not differentiate the work. Responsibilities do.
Get in Touch
Open to backend and platform engineering roles and internships.