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Oliver A.OA

Oliver A.

🚀 Senior Software Engineer

€500/day
Cádiz, ES
15+ years

Average response time: 1 hour

About Oliver

I am a Staff-level Software Engineer and tech founder with 12+ years of experience building and scaling products for startups and scale-ups. I specialise in full-stack and platform architecture, shipping end-to-end solutions from fuzzy idea to production systems.

Recently, I led the creation of CrimeMapX.com, an AI-powered crime analytics platform. I designed and delivered tools using MCP, agents, LangChain, LLMs, RAG, and vector databases to turn noisy public data into actionable insights, owning everything from backend orchestration and data pipelines to product delivery and go-to-market experiments.

Before that I spent three years at 90POE on the Platform/Core team, working on complex micro-frontend architectures, performance, and developer experience, and now I focus on Staff-scope work at UserTesting across frontend, backend, infra, and AI. My work usually sits at the seams: platform engineering, observability, migrations, and AI integrations that other teams can safely build on.

I enjoy mentoring, clarifying messy problems, and collaborating across teams. I am most effective when solving hard technical problems that also require product thinking and business context, always aiming for systems that are reliable, understandable, and commercially useful.
  • Spanish

    Native or bilingual

  • English

    Fluent

Remote only
Primarily works remotely

Experience

  • Usertesting.com
    Staff Software Engineer
    January 2026 - Today (7 months)
    Seattle, WA, USA
    Staff-scope IC. I own cross-team work that sits at the seams (frontend, backend, infra, AI) and ship it end-to-end.
    • ● Architecture, backend and infra: lead micro-frontend migrations across multiple repos and orgs, modernize serverless deploy pipelines, ship features on Scala microservices, migrate them to NestJS with agnostic end-to-end tests, and extend Terraform stacks and Datadog monitoring so services are production-ready by default.
    • ● Guild, docs and AI: drive the engineering guild, improve core docs and decision records, and lead AI initiatives around SDD with OpenSpec, agents and skills, token-usage optimization, and step-by-step adoption plans.
    • ● AI / MCP / RAG: co-create an MCP-powered domain assistant using MongoDB Atlas Vector Search to enhance context retrieval, RAG to improve answer quality, Mastra to orchestrate the agent, and a self-indexing loop plus reusable agent rules and skills across repos
    • ● Stack: React, NextJS, TypeScript, NestJS, GraphQL, gRPC, AWS (Lambda, Aurora, MongoDB Atlas with Vector Search, Bedrock), Kafka, Terraform, Helm, ArgoCD, OpenSpec, MCP servers and legacy Angular microfrontends.
    Typescript React.js Software Architecture CI/CD Management Generative AI
  • CrimeMapX.com
    Founder
    June 2025 - May 2026 (11 months)
    • ● Built full-stack crime analytics platform with Next.js/React frontend and Python/FastAPI backend. Implemented advanced SSR, ISR, and hydration strategies for optimal SEO and performance. Architected platform processing 500K+ crime records with sub-200ms response times using Supabase (PostgreSQL + pgvector).
    • ● Implemented RAG (Retrieval-Augmented Generation) pipeline with LangChain, integrating OpenAI models and vector similarity search on pgvector extension. Achieved 95% semantic search relevance accuracy across crime incident data.
    • ● Deployed serverless edge functions with Deno for real-time data aggregation, achieving global CDN distribution with <50ms latency across 285+ cities worldwide.
    Python Data Cleaning and Preprocessing CI/CD Management External API integration React.js
  • 90poe.io
    Lead Software Engineer
    November 2022 - December 2025 (3 years and 1 month)
    London, UK
    • ● Architected microservices using Go and Node.js/NestJS with API Gateway pattern, handling 2M+ daily requests with 99.9% uptime. Implemented event-driven architecture with Kafka for asynchronous processing across 15+ services.
    • ● Optimized PostgreSQL database performance through query tuning, connection pooling, and implementing read replicas, reducing average query time from 450ms to 85ms (81% improvement).
    • ● Built internal platform tooling and CLI that reduced deployment time by 60% and standardized service scaffolding across engineering teams.
    • ● Implemented comprehensive observability stack (Datadog, Sentry) with distributed tracing, reducing MTTR by 70% and providing real-time insights into system health.
    • ● Led migration of monolithic services to microservices architecture, improving team autonomy and enabling parallel development across 4 squads.
    IT Architecture MySQL React.js GO MCP Server

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Education

  • Computer Science
    Oviedo University
    Computer Science

Skill set

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