# Diwash Bhandari > Senior Software Engineer | Python, FastAPI, AI/ML & System Architecture Kathmandu, Nepal · 5+ Years · Open to Opportunities ## Summary I build scalable backend systems, AI-powered applications, and multi-tenant SaaS platforms that ship fast and scale reliably. ## Highlights - Built scalable REST APIs, GraphQL APIs, and real-time backend services for cloud telephony and SaaS platforms - Integrated CRM, customer support, marketing automation, analytics, and communication platforms using REST APIs, GraphQL, webhooks, ETL pipelines, and event-driven architectures - Developed AI-powered applications using RAG pipelines, LangChain, LangGraph, vector databases, and multiple LLM providers - Designed secure authentication systems, real-time data synchronization pipelines, and scalable microservices using FastAPI, PostgreSQL, Redis, and EdgeDB (Gel) - Improved engineering quality through code reviews, mentoring, SOLID principles, CI/CD practices, and cross-functional collaboration ## Core Competencies - Backend Architecture & API Design - Cloud Telephony & CRM Integrations - Microservices & Distributed Systems - AI/LLM & RAG Applications - Event-Driven Architecture & Real-Time Systems - Performance Optimization - DevOps & CI/CD ## Services ### Backend API Development From $2,500 · 2-4 weeks High-performance REST and GraphQL APIs built with FastAPI, handling 100K+ requests/day with sub-200ms response times. Includes authentication, authorization, database optimization, and comprehensive API documentation. - RESTful API design & development - GraphQL APIs with subscriptions - Database architecture & optimization - Authentication & authorization systems - API documentation & testing **Technologies:** FastAPI, PostgreSQL, Redis, GraphQL, Docker ### AI/ML Integration From $3,500 · 3-6 weeks Production-ready AI applications — RAG platforms, LLM-powered chatbots, and document Q&A systems with 92% accuracy. Built for enterprise teams needing fast, reliable AI-powered responses. - RAG (Retrieval-Augmented Generation) systems - LLM-powered chatbots & assistants - Document processing & Q&A - Vector database integration - Multi-provider AI orchestration **Technologies:** LangChain, OpenAI, ChromaDB, Qdrant, FastAPI ### System Architecture & Consulting From $1,500 · 1-3 weeks Microservices design, monolith-to-microservices migration, and performance optimization. Reduced deployment time by 40% and scaled systems from 10K to 100K+ users with containerized infrastructure. - Microservices architecture design - Monolith decomposition - Performance optimization - System scalability planning - Code review & mentoring **Technologies:** Docker, AWS, gRPC, RabbitMQ, PostgreSQL ### Cloud Telephony Solutions From $3,000 · 3-5 weeks IVR workflows, call routing, SMS automation, and CRM integration across multiple countries with real-time monitoring dashboards. - IVR system design & implementation - Call routing & recording - SMS & notification automation - CRM integration - Real-time call monitoring dashboards **Technologies:** Twilio, DIDWW, Telynx, WebSockets, FastAPI ## Experience ### Senior Software Engineer — Freelance May 2026 - Present · Remote · Freelance / Consulting Architecting and delivering production-grade backend systems across warehouse management, large-scale member management, software licensing, and AI-powered customer support engagements. - Delivered multi-tenant warehouse management backend with real-time slot locking and operational dashboards. - Built large-scale member management platform supporting ~30M records with RBAC, caching, and ML-powered recommendations. - Designed commercial licensing server and client-side enforcement SDK with Ed25519 signatures and offline grace periods. - Shipped LangGraph-based ISP support platform with hybrid RAG, OTP-gated plan changes, and QR-code payments. **Technologies:** Python, FastAPI, PostgreSQL, Redis, Docker, AI/ML, WebSockets ### Mid-Level Software Engineer — Codavatar Tech Pvt. Ltd. June 2023 - May 2026 · Kalopul, Kathmandu · Full-time Built scalable cloud telephony and CRM integration platforms by delivering secure backend services, real-time communication systems, and event-driven integrations that improved automation, interoperability, and operational efficiency. - Built GraphQL subscription infrastructure over WebSockets, reducing client-side polling. - Led Casdoor identity integration and legacy auth migration across business-critical services. - Designed modular CRM adapter architecture used by multiple product teams. **Technologies:** Python, FastAPI, EdgeDB (Gel), PostgreSQL, GraphQL, Redis, Twilio, DIDWW, Telnyx, Casdoor ### Software Engineer — Chuchuro Firm May 2022 - July 2023 · Sinamangal, Kathmandu · Full-time Improved system throughput and reliability through distributed asynchronous architecture, intelligent caching, and Docker-standardized environments. - Introduced Celery + RabbitMQ background processing, reducing API response latency. - Integrated Meilisearch to improve full-text search relevance and speed. - Standardized Docker environments across development and staging. **Technologies:** Python, Tornado, Celery, RabbitMQ, Redis, PostgreSQL, Peewee ORM, Meilisearch, Docker ### Associate Software Engineer — Young Minds Creation (P) Ltd. December 2020 - April 2022 · Young Minds Tower, Kathmandu · Full-time Delivered production web applications for enterprise clients with reliable uptime and strong client satisfaction. - Awarded Eminent Developer of the Year for exceptional contributions to software development and innovation. - Delivered production web applications for enterprise clients with reliable uptime and strong client satisfaction. **Technologies:** PHP, Laravel, MySQL, Docker, REST APIs, Middleware ## Projects ### Warehouse Management System (WMS) Multi-Tenant Warehouse Backend — Slot Locking, Picklists, ASN/LPN, SFTP Sync & Real-Time Dashboards · Backend Systems | Warehouse Operations A multi-tenant warehouse backend that coordinates receiving, inventory, outbound picking, slot operations, and loading across tenants without conflicting updates. Real-time slot locking and reservation sync keep warehouse-floor state consistent. ASN/LPN and picklist workflows cover the full item lifecycle, while SFTP and CSV integrations sync with external systems. Operational dashboards provide visibility into traffic, pick logs, and audit history. **Technologies:** Python, FastAPI, PostgreSQL, SQLAlchemy, Redis, WebSockets, SFTP, CSV, Sentry ### Member Management System (MMS) Large-Scale Member Platform — 30M Records, Lifecycle Workflows, RBAC, Caching & Store Recommendations · Backend Systems | Enterprise SaaS A large-scale member management platform for a loyalty and club-management program, handling onboarding, lifecycle changes, card transactions, and club summaries across very large datasets. Efficient pagination and caching keep high-volume queries responsive. Member events are tracked with full audit history, while role-based access control and secure document storage maintain compliance. External sync adapters and a location-recommendation component support operational integration and store planning. **Technologies:** Python, FastAPI, Async SQLAlchemy, PostgreSQL, Redis, S3, scikit-learn, Claude API, Twilio, SFTP, CSV, Sentry ### Guard License Server Commercial Software Licensing — Ed25519 Signatures, Node-Locked & Floating Licenses, Encrypted Storage · Backend Systems | Security | Licensing A licensing server that issues and verifies commercial licenses offline using Ed25519 signatures. It supports node-locked and floating license models, with pluggable storage across MessagePack, SQLite, and PostgreSQL. AES-256-GCM encryption, rate limiting, and structured logging protect the admin API and license data. **Technologies:** Python, FastAPI, PostgreSQL, SQLite, MessagePack, AES-256-GCM, Ed25519, Docker, Loguru ### Guard Trust — License Enforcement SDK Client-Side License SDK — Offline Verification, Machine Binding, Background Monitoring & Nuitka Protection · Backend Systems | Security | Licensing A client-side SDK that enforces licenses offline by verifying Ed25519 signatures and binding licenses to machine fingerprints. It supports configurable offline grace periods, import-time validation, background monitoring, and runtime revocation detection. FastAPI middleware auto-revalidates licenses on HTTP requests, while Nuitka compilation and encrypted local caching protect source and license data. **Technologies:** Python, FastAPI, Ed25519, AES-256-GCM, PostgreSQL, Nuitka, Docker, GitLab CI/CD ### ISP Customer Support Platform LLM-Powered ISP Support — LangGraph Agent, Hybrid RAG, QR Payments, Ticketing & Live Dashboard · AI Support Platform A LangGraph-based support platform where an agent uses 16 function-calling tools to handle subscriptions, invoices, plan upgrades, ticketing, QR-code payments, and technician workflows through conversation. Hybrid RAG combines dense vector and BM25 search with Reciprocal Rank Fusion, while a dual LLM fallback maintains availability. OTP verification via RFC 4226 HOTP secures sensitive actions, and QStash processes async tasks with JWT-verified webhooks across pluggable Redis, Upstash, and PostgreSQL cache backends. **Technologies:** Python, FastAPI, LangGraph, Upstash Vector, Redis, PostgreSQL, QStash, GitLab CI/CD ## Skills - **Programming Languages:** Python, Go, JavaScript - **Backend Frameworks:** FastAPI, Starlette, Laravel, Tornado - **Frontend:** React, JavaScript, HTML/CSS - **Databases:** PostgreSQL, Redis, MongoDB, MySQL - **Ai Ml Technologies:** LangChain, OpenAI GPT, ChromaDB, FAISS, RAG Systems - **Apis Architectures:** RESTful APIs, GraphQL, gRPC, Microservices - **Devops Cloud:** Docker, AWS, Git, CI/CD - **Other Technologies:** WebSockets, AsyncIO, TDD ## Education - **Bachelor in Information Management** — [Nepal Commerce Campus (NCC)](https://ncc.tu.edu.np/) (Information Technology & Business Management · 2017 - 2021) - **Higher Secondary Education (Management - Computer Science)** — [Ambition College](https://ambition.edu.np/) (Computer Science & Business Studies · 2014 - 2016) ## Writing - [Context Engineering: The Next Evolution Beyond Prompt Engineering](https://medium.com/@diwasb54/context-engineering-the-next-evolution-beyond-prompt-engineering-94f0ea3c0f75) — Medium · January 2026. In-depth article exploring the shift from prompt engineering to context engineering for building more effective AI systems - [MVP vs SLC: Which Development Strategy Wins for Web Projects?](https://medium.com/@diwasb54/mvp-vs-slc-which-development-strategy-wins-for-web-projects-2f405ef46921) — Medium · December 2025. Comparative analysis of Minimum Viable Product vs Simple, Lovable, Complete development strategies - [Pydantic v2: 24 Features That Will Transform Your Python Code](https://medium.com/@diwasb54/pydantic-v2-24-features-that-will-transform-your-python-code) — Medium · December 2025. Comprehensive guide to new features in Pydantic v2 with practical examples and use cases ## Certifications - [Python For Beginners Course In-Depth](https://www.udemy.com/certificate/UC-8b76db5f-747b-47b2-9224-7f2f2cc79a0d/) — Udemy · October 2022 - [The Complete ReactJs Course - Basics to Advanced [2021]](https://www.udemy.com/certificate/UC-9c90c56a-2f49-41db-9b8b-2a88aef3ffc2/) — Udemy · August 2021 ## Awards - **Imminent Developer of the Year** — Young Minds Creation (P) Ltd · February 2022. Awarded on the 15th Annual Day for exceptional contributions to software development, innovation, and leadership in tech projects ## Contact - **Email:** dev@diwash-bhandari.com.np - **Phone:** +977-9861037328 - **Location:** Kathmandu, Nepal - **Availability:** Open to Opportunities - **Contact form API:** POST https://www.diwash-bhandari.com.np/api/contact - **LinkedIn:** https://www.linkedin.com/in/diwash-bhandari-3814b2157/ - **GitHub:** https://github.com/Diwas2055/ - **GitLab:** https://gitlab.com/Diwas2055 ## Machine-Readable Resources - OpenAPI 3.1 specification: https://www.diwash-bhandari.com.np/openapi.json - API documentation: https://www.diwash-bhandari.com.np/api/docs - MCP manifest: https://www.diwash-bhandari.com.np/.well-known/mcp/manifest.json - MCP endpoint (Streamable HTTP, JSON-RPC 2.0): https://www.diwash-bhandari.com.np/mcp - llms.txt: https://www.diwash-bhandari.com.np/llms.txt - Sitemap: https://www.diwash-bhandari.com.np/sitemap.xml --- - Canonical URL: https://www.diwash-bhandari.com.np/ - Source: Diwash Bhandari (www.diwash-bhandari.com.np) - This markdown is generated from the same data as the HTML page at this URL.