ERNEST/ HAYFORD

Backend ArchitectureMicroservicesGraphQL & REST APIsEvent-Driven Systems

Lead Back-End · Software Factory Engineer

APIs, payments, and event-driven platforms · agent harnesses · validation gates

View full résumé for metrics & history ↗

Services

Node/TypeScript APIs, event-driven workflows, and distributed backends

Node.jsTypeScriptExpressGraphQLRESTHono

Data

Schema design, caching layers, and data integrity at scale

PostgreSQLMongoDBRedisDrizzle

Cloud & Edge

AWS, containers, observability, and global delivery infrastructure

AWSDockerKubernetesCloudflareServerless

Interface

Composable UIs, design systems, and micro-frontend surfaces

VueNuxtReactSvelte
01

Overview

Back-End PlatformsAPIs & ScaleSoftware Factory

Eight years of backend architecture, APIs, and production reliability. Sole architect of HustleSasa backend services scaling 1M+ payment transactions daily at 99%+ uptime. Node/TypeScript microservices, payment rails, and cloud-native infrastructure serve high-traffic platforms across African markets. Live entertainment and online ticketing workloads are a focus area. Software factory work covers agent harnesses, validation contracts, and eval gates that help teams ship verified changes.

Architecture

Node/TypeScript APIs, payment services, and event-driven backends on Postgres, Mongo, Redis, and AWS/Kubernetes. Vue, React, and Svelte surfaces plus agent harnesses and validation gates when teams adopt agent-native delivery. Systems scale across every layer — platform first.

APIs & Microservices

Node/TypeScript services with clear domain boundaries. REST and GraphQL APIs, resilient messaging, and observable pipelines stay reliable under load.

Payments & Reliability

Payment rails, rate limiting, caching, and uptime discipline for high-traffic platforms — the same patterns that keep ticketing and live-event surges healthy.

Serverless & Cloud

Event-driven architectures on AWS with Docker/Kubernetes delivery — API gateways, background workers, and infra that scales without idle waste.

Software Factory Systems

Agent harnesses, validation contracts, and orchestration loops. Intake, implementation, checks, and review gates help teams produce verified changes without linear headcount.

Micro-Frontends

Module federation and independent frontend teams shipping Vue, React, and Svelte apps that compose into a unified product surface.

03

Experience

Lead Back-End / Full-Stack Engineer @ HustleSasa

  • Sole architect of 5+ core backend services and APIs for payment, campaign, and messaging across African markets
  • Scaled payment volume from $50K to $900K+/mo — 1M+ transactions/month with 99%+ uptime under high-traffic load
  • Built event-driven delivery on AWS Step Functions and SQS; cut API latency 65% via Redis caching and query optimization
  • Mentored up to 4 engineers on service ownership, reviews, and delivery practices
  • Strengthened data handling and access controls for financial and customer PII workloads
  • Shipped micro-frontend surfaces with Module Federation alongside core backend ownership

AI Operator Consultant @ Invisible Technologies

  • Designed and implemented LLM evaluation frameworks for production AI systems
  • Built quality assurance pipelines for model output validation
  • Architected agent workflows with eval gates for reliable ops automation

Senior Software Engineer @ Simple Dealer

  • Built Autofill Engine processing 1,000+ transactions/minute
  • Achieved 97% test coverage across core services
  • Designed high-throughput automotive data ingestion pipelines
  • Delivered full-stack features across Vue frontends and Node.js/Rust backends

Technical Lead @ Agro Innova

  • Led engineering team through product pivot and platform consolidation
  • Defined technical roadmap and architecture for agritech products

Full Stack Engineer @ Agro Innova

  • Built USSD platform for farmer engagement at scale
  • Developed Akoko Market marketplace and Farm Business School (FBS)
  • Implemented Bulk SMS notification system for agricultural outreach

Freelance Software Engineer @ Independent

  • Delivered full-stack and AI automation solutions for startups and SMEs across West Africa
  • Built software factory patterns, internal tools, and agent workflows that multiply team output
  • Specialized in API design, agent orchestration, cloud infrastructure, and payment integrations

Projects

HMS

Full-stack hospital management system for clinics in Ghana: patient registration, OPD triage, billing, and role-based access

Vue 3HonoPostgreSQLDrizzleBetter AuthCloudflare R2

Standalone Autofill Engine

High-performance automotive data autofill engine rewritten in Rust

Rust

Agent Revenue Pipeline

Agent workflow: Clay enrichment and signal triggers feed n8n orchestration and HubSpot CRM. LLM agents handle lead research, routing, and outbound. Eval gates run before any prospect contact.

Clayn8nMakeHubSpotPythonTypeScriptLLM APIs

My Approval

Serverless platform for automating approval and workflow routing across departments

NuxtServerlessAWS
Visit ↗

Hami Express

GraphQL library for building schema-first APIs with minimal boilerplate

GraphQLNode.jsTypeScript
Repository ↗

SST Deploy

GitHub Action for deploying SST applications to AWS with zero config

GitHub ActionsSSTAWS
Repository ↗

Stack

Languages & Frameworks

  • TypeScript
  • Node.js
  • Express
  • Hono
  • GraphQL
  • Python
  • Rust
  • Mojo
  • Vue
  • Nuxt
  • React
  • Svelte

Databases & Caching

  • PostgreSQL
  • MongoDB
  • Redis
  • DynamoDB

Cloud & Infrastructure

  • AWS
  • Docker
  • Kubernetes
  • Serverless
  • SST
  • Cloudflare
  • Edge Computing

Architecture & Patterns

  • Microservices
  • Event-Driven
  • Distributed Systems
  • Payment Infrastructure
  • REST & GraphQL APIs
  • Serverless
  • Micro-Frontends
  • Module Federation

AI & Automation

  • AI Engineering
  • Software Factory Engineering
  • Agent Orchestration
  • Agent Harness Design
  • LLM Evaluation
  • Workflow Automation
  • Validation Contracts

Software Factory

  • Agent Harness
  • Validation Contracts
  • CI/CD Gates
  • Orchestration

Practices & Domains

  • Fintech
  • Payment Infrastructure
  • CI/CD
  • Test-Driven Development
  • Data Security & Privacy
  • Software Factory Systems
  • AI Engineering
06

Polyglot

TypeScript is home base. Other languages fit when the problem demands a different shape: memory safety, numeric performance, or AI-native tooling.

TypeScript

Production

Primary language for full-stack delivery: typed Vue/React frontends, Node services, shared contracts, and most production systems.

Rust

Experimenting

Systems programming experimentation: memory safety, concurrency, and performance patterns before production use.

Python

Active, when needed

AI agent pipelines, harness scripts, data tooling, and backend prototyping — the default reach for LLM-powered systems.

Mojo

Exploring

Early exploration for machine learning workloads: Python-like ergonomics with a path toward bare-metal performance for model-centric systems.

Software Factory

HarnessValidationDelivery

Build the factory, not every feature

Software factory engineering designs the system that produces software. Intake rules, agent orchestration, validation harnesses, and review gates turn backlog into verified output. Platform discipline keeps the line reliable under load.

Agent harness design

Orchestrator, worker, and validator roles with serial gates. Tasks carry acceptance criteria before any agent edits code.

Validation contracts

Numbered checks gate done from proven. Eval gates run before merge, release, or outbound contact.

Durable orchestration

File-backed state and loop-until-goal runs survive crashes and long jobs without chat memory.

Platform governance

CI/CD pipelines, sandboxes, observability, and autonomy policies control what agents can change and ship.

AI Engineering

ModelsMechanicsMastery

AI engineer, not AI user

Production AI systems sit on solid platform foundations: agent orchestration, evaluation frameworks, inference pipelines, and reliability layers that turn demos into production. LLM eval and QA work applies the same gate pattern as software factory validation contracts.

Agent orchestration

Multi-step LLM workflows for research, enrichment, routing, and follow-up. Tool use, guardrails, and human handoff when confidence is low.

Evaluation & benchmarking

Eval frameworks for LLM outputs: quality scoring, regression detection, and production safety gates before release.

Inference engineering

Latency, context windows, batching, and deployment patterns for fast, observable, dependable models in real products.

Model mechanics

Transformers, attention, embeddings, and architecture choices that shape capability and cost. Production systems are designed with limits in mind.

Life

Engineering is the craft, but balance keeps the edge sharp. Competitive games, pitch time, and the occasional jog keep me grounded outside the terminal.

Gaming

Apex Legends

Fast-paced BR: movement mechanics and team coordination.

FIFA

Football on the couch: tactics, seasons, and competitive matches.

Rainbow Six Siege

Tactical FPS: map knowledge, operator synergy, and clutch rounds.

Fitness & Outdoors

Swimming

Laps for clarity: low-impact cardio and a break from the screen.

Football

Pickup matches with friends on grass.

Basketball

Casual runs and shoot-arounds: competition without league fees.

Jogging

Morning or evening runs for focus and fitness.

Build Platform Systems

Open to Lead Back-End, platform engineering, and software factory roles. AI systems consulting remains available.

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© 2026 Ernest Hayford · Accra, Ghana