Muhammad Hashim
Islamabad
Summary
I build sophisticated data-driven web apps and specialize in complex relational data, and highly expressive simple code. I pride myself on finding clean, thorough, requisite solutions to the problems that matter, and on my dedication to my clients' big-picture business needs and the end users' happiness.
Overview
1
1
year of professional experience
Work History
Senior Backend Software Developer
Intuon Group
Islamabad
07.2025 - Current
- Led backend architecture and development of a multi-tenant fintech accounting platform built from scratch using NestJS, TypeScript, and TypeORM.
- Built a full-featured quotations engine supporting VAT rules, multi-currency pricing, discounts, tax categories, and precision-safe financial calculations using Decimal.js.
- Architected transactional financial calculations with deterministic rounding strategies to prevent floating-point inaccuracies in accounting workflows.
- Implemented complex quotation lifecycle management, including drafts, issuance, history tracking, email delivery, duplication, and conversion to proforma invoices.
- Developed dynamic VAT logic supporting standard, zero-rated, exempt, and out-of-scope categories, aligned with UAE tax requirements and B2B/B2C rules.
- Designed scalable pagination, filtering, and search systems for financial resources, with advanced query builders and optimized database access patterns.
- Engineered Stripe subscription integration, including checkout sessions, webhooks, billing lifecycle management, and subscription state synchronization.
- Built a secure public quotation-sharing system with expiring stateless tokens and protected link generation.
- Designed file upload architecture using Google Cloud Storage, with object naming strategies and access control for documents, attachments, and media.
- Established a modular monorepo architecture (Nx) with shared backend and frontend utilities for consistent financial calculation logic.
- Led backend engineering decisions, technical planning, and feature architecture for the accounting domain.
Senior Backend Engineer
RFZ Digital
Islamabad
09.2024 - 06.2025
- Led the design and development of a fintech-based, multi-currency, fractional real estate product.
- Led backend enhancements for authentication architecture by implementing refresh token-based auth flows, improving session security, and token lifecycle management for mobile clients.
- Designed and integrated KYC/AML verification workflows using DidIt, including onboarding status tracking, webhook handling, and verification state synchronization.
- Integrated Firebase Cloud Messaging (FCM) to enable real-time push notifications for iOS and Android builds (deposit confirmations, verification updates, and platform events).
- Designed and implemented back-end APIs for property listing management for fractional real estate investments.
- Developed scalable listing retrieval endpoints with filtering and pagination to support a mobile-first UX.
- Led the complete migration from DidIt to IDWise for KYC/AML verification — fully owned architecture, implementation, and rollout.
- Designed a new integration layer for IDWise APIs, including identity verification, document processing, and AML screening.
- Implemented webhook processing and verification status reconciliation for IDWise.
- Initiated and architected integration with Fireblocks for secure crypto custody infrastructure.
- Built scalable logic to support USDT and USDC across multiple blockchain networks (EVM and non-EVM).
- Secured web hook endpoints and implemented IP whitelisting for transaction event validation.
- Evaluated SDK vs. REST API approaches and chose REST for reduced dependency overhead.
- Conducted extensive R&D on double-entry accounting systems for fin-tech-grade money movement.
- Evaluated Ledger-as-a-Service providers versus in-house implementation for scalability and regulatory control.
- Ensured architecture alignment with compliance requirements and fraud prevention standards.
- Designed and implemented back-end services to synchronize Fireblocks transaction updates (deposits, transfers, withdrawals) with Rewoa’s internal systems.
- Built web hook consumers to process transaction life cycle events (submitted, confirmed, failed).
- Ensured idempotent transaction handling to prevent duplicate ledger entries.
- Initiated integration with Blnk Finance to introduce structured double-entry ledger capabilities.
- Established financial transaction flow, custody event -> Ledger entry -> Wallet balance update.
- Successfully implemented multi-currency wallet balance persistence for users (supporting USDT, USDC, and USD).
- Designed balance aggregation logic sourced from ledger entries instead of a mutable wallet state.
- Built a wallet–ledger synchronization service, ensuring accurate available balance, pending balance tracking, and atomic state updates.
- Implemented safeguards to prevent double-spend scenarios during concurrent requests.
- Integrated dynamic network fee retrieval from Fireblocks for real-time withdrawal cost estimation.
- Introduced a Redis-based caching layer to reduce repeated external API calls.
- Optimized fee estimation performance, and reduced Fireblocks API overhead.
- Implemented TTL-based cache invalidation strategy for accurate, yet performant, gas price updates.
- Improved user experience by surfacing real-time network fee data during the withdrawal flow.
Education
Bachelor of Science - Software Engineering
COMSATS University
Lahore08.2020
Timeline
Senior Backend Software Developer
Intuon Group
07.2025 - Current
Senior Backend Engineer
RFZ Digital
09.2024 - 06.2025
Bachelor of Science - Software Engineering
COMSATS University