Personal details

Yosvel Q. - Remote full-stack developer

Yosvel Q.

Software Engineer
Based in: 🇪🇸 Spain
Timezone: Bangkok (UTC+7)

About

Senior Full-Stack Engineer | TypeScript, Multi-Tenant SaaS & Distributed Systems | AI Agents

Full-Stack Engineer with 15+ years in software development, building multi-tenant SaaS platforms across fintech, insurance, HR-tech and facility management. Specialized in TypeScript, Node.js/NestJS and Nx monorepos, with repeated experience in legacy JavaScript-to-TypeScript migrations. Extends core full-stack engineering with AI agent orchestration (LangChain, LangGraph), building automation into the product itself rather than bolting it on as a side feature.

Core Skills

  • AI & Agentic Systems: LangGraph (stateful graphs, Postgres checkpointing), LangChain, Claude API, OpenAI API, Gemini API, pgvector / RAG, LLM extraction & structuring pipelines, prompt eval sets
  • Languages: TypeScript, JavaScript (ES6+), SQL
  • Backend & Architecture: Node.js (NestJS, Express), modular monoliths, contract-first APIs (Zod, oRPC, OpenAPI), REST, GraphQL, event-driven systems (BullMQ, transactional outbox), Drizzle, TypeORM, Mongoose
  • -Frontend: Next.js (App Router, RSC), React, React Native, TanStack Query/Table, Zustand, Redux, Angular (NgRx, RxJS), Vue (Vuex), Tailwind CSS, shadcn/ui
  • Data & Storage: PostgreSQL (RLS, multi-tenant design, pgvector), MongoDB, Redis, MySQL, DynamoDB
  • Cloud & DevOps: AWS, Google Cloud, Azure, Supabase, Docker, CI/CD (GitHub Actions, CircleCI), Nx monorepos
  • Testing: Playwright, Vitest, Jest, Cypress, Mocha/Chai
  • Also worked with: Hono, Nuxt (Pinia), Better Auth, Stripe (subscriptions, webhooks, metered billing), Clerk, Resend, Sentry, Coolify, Uptime Kuma, Crawlee, pgTAP, Kafka, RabbitMQ

Work Experience

Independent Contractor, Software Engineer
Arc.dev | Sep 2022 - Present
Node.js
MongoDB
TypeScript
Docker
React
Jwt
JavaScript
GraphQL
NestJS
Tailwind css
Playwright
Zustand
Supabase
Langchain
Langgraph

Independent Contractor, Remote · direct clients; via Arc.dev since Oct 2024

  • Rebuilding a legacy ASP.NET MVC / SQL Server facility-management system (~90 controllers, 130+ tables, 120+ stored procedures, 110+ reports) as a multi-tenant NestJS modular monolith in an Nx monorepo (Next.js, oRPC, Drizzle, Supabase), after delivering the technical review and estimate that scoped it.
  • Migrated the legacy data (7,500+ contractor records, 3,000+ contacts) and demoed working modules on it to the client, with Microsoft Entra ID sign-in end to end.
  • Enforced row-level tenant isolation with Postgres RLS plus scoped query factories, verified by cross-tenant leakage tests that run through the connection pooler under load.
  • Built a durable event backbone on a transactional Postgres outbox and BullMQ, with idempotent consumers, dead-letter queues and graceful shutdown.
  • Established a contract-first workflow where Zod schemas drive DB, API and UI types, backed by 750+ automated tests (Vitest unit/integration, 85+ Playwright end-to-end).
  • Earlier engagements: full-stack features for multi-tenant products, including a creator-economy platform, a gaming-community platform and an AI capital-markets intelligence platform (Nx, NestJS, Next.js; GraphQL + Mongoose/MongoDB, TypeORM + REST); Stripe subscriptions and webhooks for a fintech budgeting app; Angular (NgRx, RxJS) and Vue (Vuex) frontends.

Tech: TypeScript, Node.js, NestJS, Next.js, React, oRPC, Zod, Drizzle, Supabase (Postgres, RLS, Auth), BullMQ, Redis, LangChain, LangGraph, TanStack Query, shadcn/ui, Tailwind, Zustand, Nx, Playwright, Vitest, GitHub Actions

Lead Software Engineer
YPB Group | Feb 2022 - Aug 2022
Node.js
Amazon EC2
Lambda
TypeScript
Docker
JavaScript
Jest
AWS DynamoDB
Postman
RESTful API
NestJS
Express.js
AWS
  • Joined a team running many AWS Lambda microservices spread across separate repositories, many in plain JavaScript; consolidated them into a single Nx monorepo of TypeScript NestJS applications with shared logic and types.
  • Refactored services consuming AWS (Lambda, S3, RDS, DynamoDB), so a class of errors that only appeared at runtime is now caught at compile time.

Tech: TypeScript, NestJS, Express.js, AWS (EC2, Lambda, S3, RDS, DynamoDB, IAM), Nx, Docker

Projects

OmniCore
2026
Next.js
NestJS
Nx
Supabase
Langchain
Langgraph
AI data engine (own product, private): solo-built Nx monorepo of contract-first services. Agentic pipeline with LangChain and LangGraph for tiered ingestion (API → RSS → HTTP → headless), structured extraction and translation, with a per-run cost ledger and circuit breaker.
Slack Anonymizer
2025 | https://github.com/yosvelquintero/slack-anonymizer
TypeScript
RESTful API
Openapi specification
slack-anonymizer: Hono REST API that strips PII from Slack exports (hashed user IDs) and reports sentiment and usage statistics; Zod validation, OpenAPI 3 docs.

Education

University Silverio Blanco Núñez
Bachelor's degree・BSc, Mathematics and Computation
Jan 1996 - Jan 2002

Certifications & Awards

React: Components, Context, and Accessibility
LinkedIn | Sep 2024
Arc Certified Remote Developer
Arc.dev | Sep 2024