Idempotency: A Deep-Dive Triggered by a Real-World Double-Charge Failure
Payments should never charge twice. I break down Post/Redirect/Get, idempotency keys, and storage-layer guarantees that keep retries from corrupting state.
Read on MediumHi, my name is
Umar Ejaz Imam.
I am a Software Engineer who likes building reliable systems and backend infrastructure.
About Me
I work on backend services, automation, and platform reliability. I enjoy improving how systems run in production, making deployments smoother, and building tools that keep platforms stable. I’ve worked with C++, Go, Python, Node.js, Linux, containers, and cloud tooling to ship services that stay predictable under load.
Most of my work centers on clean automation, observability, and infrastructure that scales without drama.
Contact Me
Professional Experience
Siemens Technology
Software Developer
Python · Flask · PostgreSQL · Grafana · pandas · openpyxl · python-docx
- Built a backend analytics and automation platform used across 20+ engineering teams for bug classification, release tracking, and operational reporting.
- Designed configurable ingestion pipelines to process inconsistent Azure DevOps/TFS exports with schema normalization, dynamic headers, duplicate-column handling, and bounded extraction workflows.
- Developed a hybrid rules-based classification engine spanning 18+ functional domains using prioritized keyword matching and override mappings for automated defect categorization.
- Implemented regression spike detection and trend analysis pipelines with functional-area attribution for release-quality monitoring and anomaly detection.
- Built PostgreSQL-backed Grafana dashboards and automated DOCX reporting pipelines with LLM-assisted summaries, reducing manual reporting time from ~6 hours to under 2 minutes (~99% reduction).
Marine Edge
SDE Intern
- Refactored legacy PHP workflows into modular backend services with improved validation, maintainability, and clearer service boundaries.
- Designed REST API contracts for payment integrations, improving backend consistency and workflow reliability across service interactions.
- Implemented validation, error handling, and state management logic to prevent duplicate transactions and invalid payment flows.
- Improved backend reliability by debugging integration failures and strengthening service behavior across critical workflows.
Featured Projects
payeazie
Live DemoNode.js · Express · TypeScript · React · Supabase · Render
- Built a payment orchestration platform simplifying multi-gateway transactions with modern full-stack engineering, emphasizing scalability and authentication.
- Designed a layered architecture with worker queues for charge and reconciliation flows, per-user dashboards, comprehensive error handling, and real-time lifecycle polling.
- Deployed with automated GitHub Actions to Render using Supabase for persistent storage, staging/production environments, and full observability.
FixItDaddy
Python · FastAPI · Go · Chronos · PostgreSQL · Redis · Docker · Kubernetes
- Built an autonomous remediation control plane where Vigil detects issues, evaluates policy, and decides when to trigger remediation through Chronos.
- Designed the service split so Vigil stays the decision plane while Chronos handles durable scheduling, worker execution, retries, and dead-letter recovery.
- Hardened the integration contract around idempotency, tenant isolation, auditability, and deterministic status sync back into incident timelines.
- Expanded the operational story with correlation persistence, fail-safe retries, and end-to-end contract validation for duplicate, failure, and recovery paths.
TorrentEdge
Node.js · Express · Kafka · Nginx · Docker · Redis
- Developed a distributed P2P file-sharing platform using Kafka event streams for real-time peer discovery, status updates, and reliable synchronization.
- Architected a scalable node network with Nginx load balancing, Docker containerization, and Redis caching for fast peer lookups and connection management.
- Implemented resilient communication patterns with automatic retry logic, exponential backoff, and optimized peer synchronization to ensure reliable transfers under network volatility.
Order Execution Engine
Node.js · TypeScript · Fastify · PostgreSQL · Redis · BullMQ · Docker
- Built an asynchronous backend system with explicit state handling and idempotency guarantees for distributed order workflows.
- Implemented a worker pipeline with BullMQ, automatic retries, and structured failure handling, reducing downtime by 12%.
- Validated service coordination and runtime behavior of Dockerized services deployed on Linux with comprehensive error recovery.
Other Notable Projects
CipherNet
Node.js · Express · Docker · OpenVPN · IPsec
- Built a secure VPN platform with Node.js and Express offering encrypted tunnels and global server routing.
- Implemented JWT-based authentication, role-aware management, and encrypted file transfer workflows.
- Packaged OpenVPN/IPsec configurations inside Docker for reproducible deployment and real-time health monitoring.
LogWise
FastAPI · React · Tailwind CSS · Ollama · Docker
- Delivered an AI-assisted log analyzer that digests massive server logs into natural-language summaries using local LLMs via Ollama.
- Built a FastAPI backend with React + Tailwind UI for fast uploads, context-aware triage, and actionable diagnostics.
- Packaged the stack with Docker Compose, keeping analysis offline while exposing root causes, warnings, and remediation hints instantly.
Taska
TypeScript · Node.js · Next.js · PostgreSQL · Redis · Kafka · Nginx
- Architected a decentralized blockchain platform with microservices for consensus, staking, wallet ops, and explorer queries.
- Implemented services in TypeScript (Node.js) with Next.js frontends backed by PostgreSQL, Redis caching, and Kafka streams.
- Hardened ingress with Nginx and containerized deployment for scalable, secure infrastructure.
Ecom Microservice GraphQL
Node.js · GraphQL · Kafka · MongoDB · Docker
- Composed independent user, product, and order services behind a federated GraphQL gateway for a unified ecommerce API.
- Streamed cross-domain signals with Kafka, pairing producers/consumers to keep services eventually consistent and auditable.
- Containerized the stack with Docker Compose, wiring MongoDB per service plus automated Jest coverage for resolvers and APIs.
Terminal Time Traveler
C++17 · nlohmann/json · Docker · CLI
- Built a retro-inspired CLI explorer that parses modular JSON timelines to surface events for any year instantly.
- Leveraged modern C++17 with nlohmann::json for fast file parsing and extensible data loading.
- Containerized the workflow with Docker so the tool runs consistently across environments and doubles as an educational reference.
- Documented extension paths—additional JSON feeds, fuzzy search ideas, and CLI hooks—to guide contributors toward new features.
ClickHouse Flat File Ingestion Tool
Node.js · Express · ClickHouse · CSV · JWT
- Shipped a bidirectional ingestion app that syncs ClickHouse tables with CSV flat files from a web UI.
- Implemented JWT-secured Express APIs with column-level selection, record counts, and detailed status reporting.
- Orchestrated file uploads, previews, and CSV transforms using multer, csv-parser, and json2csv for smooth operator workflows.
DivvyMate
Node.js · Express · GraphQL · PostgreSQL · Redis · Kafka · Docker
- Designed a microservices backend for daily expense sharing with REST + GraphQL APIs across user, expense, and balance domains.
- Handled splits via equal, exact, and percentage modes while broadcasting events through Kafka for real-time updates.
- Backed services with PostgreSQL (Sequelize ORM), cached hot data in Redis, and fronted everything with Nginx and Dockerized deployment.
NexRule
Node.js · Express · MongoDB · AST · Docker
- Created an AST-driven rule engine that lets teams compose, combine, and evaluate rules like "age > 18 AND status == 'active'" on the fly.
- Persisted dynamic rule definitions in MongoDB with Express APIs for creation, evaluation, and management.
- Containerized the stack with Docker and shipped Jest/Supertest coverage to validate evaluation paths.
- Exposed WebSocket hooks so evaluators can watch rule outcomes change live as data or expressions update.
FortFile
Node.js · Express · MongoDB · JWT · RBAC
- Developed a secure file-sharing backend with JWT auth, bcrypt hashing, and role-based access control tiers.
- Implemented subscription-driven limits (Free, Basic, Premium) governing file sizes and permissions.
- Hardened the API with Helmet, CORS policies, and structured controllers/middleware for maintainability.
- Layered in audit logging and centralized error handling to trace uploads/downloads and troubleshoot issues quickly.
Featured Blogs
TorrentEdge — A Distributed BitTorrent Client
Reimagining BitTorrent for the cloud era with Node.js, Kafka, MongoDB, and Docker—covering architecture choices, observability, and scaling lessons.
Read on MediumEducation & Coursework
BMS Institute of Technology
B.E. in Information Science and Engineering · 2021 – 2025 · Bengaluru, Karnataka
Coursework: Data Structures & Algorithms, Object-Oriented Programming, Operating Systems, Database Management Systems, Computer Networks.
Certifications: Fundamentals of Backend Engineering, Docker Networking: Creating, Managing, and Troubleshooting Container Networks, Prometheus & Grafana: Monitoring Application Performance, Software Architecture: Patterns for Developers, Advanced Linux Networking and Security.
Skills
Languages & Patterns:
C++ · Python · Go · JavaScript
Distributed Systems · Event-Driven Design · Clean Architecture
Tools & Infrastructure:
AWS · GCP · Docker · Linux
GitHub Actions · Jenkins · GitOps
PostgreSQL · Redis · Kafka · BullMQ
Observability & Reliability:
Grafana · Azure DevOps APIs · GitLab APIs
REST API Observability · Incident Automation · Chaos Testing