Onyedikachi Ejim
Backend Engineer
Four years of hands-on software engineering experience since 2022. I design and build backend systems for marketplaces, payments, operations, healthcare, and data-heavy products, covering APIs, business workflows, databases, webhooks, real-time features, and production reliability.
CORE TECHNICAL COMPETENCIES
ENGINEERING EXPERIENCE
PropTech & Marketplace platform for property listings and roommate matching in Nigeria.
- Architected versioned NestJS REST backend serving React Native mobile and Next.js web applications.
- Implemented real-time private chat using Socket.IO, message persistence, and delivery fallback notifications.
- Built automated Paystack payment pipeline for Premium subscriptions, handling signed HMAC webhooks and idempotency checks.
- Optimized listing search and filter queries in PostgreSQL with multi-column composite indexing.
Fintech platform powering digital wallets, merchant onboarding, and payments.
- Contributed Node.js backend microservices for core merchant wallets, payout disbursements, and ledger transactions.
- Integrated distributed Redis mutex locks to enforce atomic balance operations across concurrent disbursement attempts.
- Built KYC compliance pipelines for merchant identity verification and tier-based transaction limits.
- Handled background status reconciliation loops for third-party banking provider webhooks.
Municipal & commercial waste management logistics software in South Africa.
- Designed NestJS microservices and PostgreSQL schemas for field collection logging and depot storage tracking.
- Implemented strict state machine transitions enforcing valid status progression across collection crews.
- Engineered batch payload endpoints allowing offline mobile driver queues to sync upon signal restoration.
Digital healthcare infrastructure supporting RxKonet pharmacy management and myRx patient portal.
- Developed APIs for pharmacy inventory management, drug dispensing records, and patient prescription refills.
- Enforced strict role-based access control ensuring patient Health Identifiable Information (PHI) remained strictly isolated.
- Implemented custom log formatters stripping sensitive patient data prior to log aggregation streams.
Embedded ESP32 energy hardware telemetry connected to cloud ingestion and live monitoring dashboard.
- Configured ESP32 firmware MQTT telemetry publishing to AWS IoT Core over mutual TLS authentication.
- Built Node.js telemetry consumer downsampling high-frequency power readings into PostgreSQL time-series tables.
- Streamed near-real-time electrical telemetry updates to monitoring web dashboards via WebSockets.
Configuration-driven crypto exchange data ingestion and quantitative strategy execution engine.
- Built unified Python exchange adapters wrapping Bybit, Bitget, and BingX REST/WebSocket APIs with HMAC signing.
- Designed Pandas and SQLite data pipelines for tick-to-candle aggregation and strategy backtesting.
- Engineered hard risk controls including maximum order sizing, balance checks, and panic kill-switch daemons.
EDUCATION & PROFESSIONAL STATUS
Graduated with strong technical foundation
Status: Available for Remote & Hybrid Backend Engineering positions globally.