Backend Engineer

Open to full-time

Bio

Wahab E is a Backend Engineer with several years of experience in scalable API development and high-performance backend architectures. Wahab's core stack includes Ruby on Rails, Grape, PostgreSQL, Redis, and AWS. He builds robust APIs and backend systems, focusing on performance tuning and security practices like token-based authentication and IP-based rate limiting. His work often involves integrating complex systems, such as payment gateways and CRM platforms, within a microservices architecture. At Elgrocer by Smiles, Wahab developed production systems handling over 50,000 daily requests, cutting database load by 60% through Redis caching and Sidekiq processing. He also reduced campaign setup time by approximately 70% with an Angular feature module for TopSort campaigns, integrating real-time previews and RBAC controls. Wahab holds a Bachelor of Computer Science from FAST (National University of Computer and Emerging Sciences). He is well-suited for roles that require building and optimizing scalable backend systems, particularly in e-commerce and high-traffic environments.

Expertise

Ruby on RailsRelational DatabaseDocument DatabaseDatabase CachingAWSAngularHTMLCSSJavaScriptGitGraphQL

Video Intro

Assessments

General Coding and Video Assessment

(90/100)

Implement LRU Cache AlgorithmHard
Optimize Angular E-commerce Platform PerformanceMedium

Projects

Top Sort Campaign Manager – Angular & Rails

Built an Angular feature module enabling marketing teams to schedule TopSort campaigns where partner brands bid for top placement in category listings. Integrated with TopSort APIs to fetch auction data, manage bids, and sync updates with Rails. Implemented reactive forms, RBAC controls, and real-time previews to reduce campaign setup time by ~70%.

B2B Partner Onboarding & Rewards – El Grocer by Smiles

Developed a Rails-based onboarding workflow with CRM integration. The system auto-identifies partner employees via domain matching, unlocking company-specific discounts, promotions, and tiered rewards. Added dashboards to track engagement, payouts, and campaign performance. Stack includes Rails, PostgreSQL, Redis, Sidekiq, Grape APIs, AWS S3.

Multi-Shipment Order Orchestration

Refactored checkout to split a customer order into multiple retailer/warehouse-based child shipments. Built a scheduler for smart carrier assignment, partial cancellations, and safe refunds. Integrated Locus APIs for accurate ETAs and sequencing. Improved dispatch speed, reduced order delays, and enhanced support visibility.

Experience

Software Engineer
elgrocer by smilesAug 2023 — Present
- Designed and maintained RESTful APIs handling 50K+ daily requests across multiple versions using Grape, token-based authentication, and RBAC.
- Integrated Tabby installment gateway and built a wallet transaction engine with credit/debit flows.
- Developed promo system with advanced discount rules, usage limits, and B2B-specific campaigns.
- Implemented multi-shipment order architecture and integrated Locus API for real-time ETAs.
- Built AI-driven vehicle assignment logic for optimized delivery routing.
- Reduced database load by 60% using Redis caching, N+1 query elimination, and Sidekiq background jobs.
- Implemented IP-based rate limiting, OTP-based bilingual email verification, and configurable throttling.
- Automated B2B onboarding via CRM integration enabling real-time rewards accrual and tier-based benefits.
Ruby on RailsGrapeRESTful APIsSidekiqResquePostgreSQLMongoDBRedisSQLiteGitHubDockerMicroservices ArchitectureAngularHTMLCSSJavaScriptCoffeeScriptGraphQLAlgolia SearchMetabaseTabbyOnline Payment GatewaysAWS (S3)HerokuAzureRack::AttackActive Interactioni18nThrottling