End-to-end software engineering for enterprise-grade needs
I cover the full cycle —architecture, backend, AI, frontend and DevOps— with the rigour of someone who has spent over 10 years building and operating software in production, for private companies and government. Distributed platforms, ERPs, POS with electronic invoicing, and fintech — live in production.
Track record
Over a decade building and operating production systems — for private companies and the public sector. These are the roles behind every delivery.
Humanizar Systems
2022 — present
Multi-tenant SaaS ecosystem in production: e-commerce, POS with DIAN electronic invoicing, credit fintech and WhatsApp messaging, integrated through a central hub.
Finca Directa S.A.S
2021 — present
Technical leadership of a multi-tenant platform: OMS, RPA business automation, invoice OCR and CRM sync. Services agreement.
Indie Levels Studio S.A.S
2021 — present
Backend development on scalable services and production APIs. Fixed-term contract.
Critertec
2024 — 2026
Real production operations: Linux, networking and VPN, observability (SIEM), GCP and Docker. Fixed-term contract, ended 2026.
Soy Digital — Dominican Government (INDOTEL)
2023
Government project via Critertec: offline-first frontend with IndexedDB, data synchronisation and analytics for digital-enablement audit.
Agora: a distributed AI-agent platform in production.
A user edits documents, runs real Linux terminals in the browser, and talks to an AI agent that executes tools (git, kanban, shell, formal logic) inside its own workspace. A genuinely distributed system, live in production — and the clearest demonstration of the engineering level I bring to every project.
Capabilities
A complete engineering service: I cover the entire lifecycle of a serious system, from architecture to deployment. This is what I put to work on your business.
AI architecture and agents
Multi-tool agents, RAG and real-time streaming over interchangeable OpenAI, Anthropic, Gemini and DeepSeek providers.
Large-scale distributed systems
Microservices, real-time (WebSockets), versioned contracts and HMAC security — enterprise-level architecture, proven in production.
ERPs, POS and fintech
DIAN electronic invoicing, payment gateways (Mercado Pago / Wompi), real-time inventory and credit portfolio management.
Automation and integration
OCR, API connectivity, CRM sync and webhooks: pipelines that run on their own and do not break.
DevOps and SysAdmin
Docker, GCP / Cloud Run, VPN, reverse proxies, observability and encrypted backups. Real production, not demos.
Solid backend (NestJS / Node)
Scalable APIs on PostgreSQL, with auth and queues, designed to grow without rewriting.
Real systems in production
Proof before promise. Systems I designed and built, running today — go and check.
Agora
Distributed AI-agent platform: real Linux terminals in the browser and an agent executing real tools across separate services, deployed and running.
Live · viewGraf
Multi-store e-commerce (Humanizar): catalogue, real-time inventory, checkout and payment gateway. NestJS + PostgreSQL + Next.js, in production.
Live · viewSinergia POS
Point of sale with DIAN electronic invoicing, cash drawer, taxes and multiple gateways. PWA that keeps selling without internet.
Live · viewFIAR
Credit fintech (Humanizar): loan portfolio, recurring payments and analytics dashboard on NestJS + TypeORM + Mercado Pago, in production.
Live · viewCristina CMS
Custom editorial CMS in Next.js + Neon Postgres, foundation for media outlets and corporate blogs.
Live · viewSoy Digital
Systems for the Dominican Government (INDOTEL, via Critertec): offline-first frontend with sync and data analytics for digital-enablement audit.
Live · viewWhat I can do for you
Pick the one that matches your need. If it is not on the list, write to me anyway — I will most likely solve it.
AI-powered WhatsApp chatbot (24/7)
Your business responds, qualifies and schedules on its own — you stop losing sales from slow replies. Built on the official WhatsApp API, with your tone and your rules.
AI automation
Whatever steals your hours today, the system does on its own: document OCR, multi-app flows, CRM sync and automated replies. I connect everything you already use.
AI photo upscaling and restoration
Blurry or low-resolution images come out sharp and professional, in batch. Catalogue ready to sell within 48 h.
AI brand asset pack
Up to 50 consistent visual pieces for social media and campaigns, AI-generated and hand-curated. Your brand ready to publish.
Custom backend and systems (NestJS / Node)
When the problem is genuinely large: ERPs, CMS, RAG and AI integrations. I diagnose the root and build the whole system — no patches.
Landing page or conversion-focused website
Next.js sites, fast, SEO-ready and built to sell. Instant load and ready to receive clients.
How we work
Straightforward, low-risk and with results you can see.
1. Diagnose the real problem
I understand your business structure before writing a single line of code. No generic solutions.
2. Architectural design
I design a scalable solution sized to your need — no over-engineering, no useless dependencies.
3. Full execution
I build the whole system — backend, AI, frontend and deployment — at startup speed with production rigour.
4. Production and support
Delivered in production, tested and documented. And I stay with you for maintenance and monthly support.
Have an idea or a headache?
Tell me in a short call and you will leave with a clear plan and a fixed price. No commitment — write to me now.
Prefer email? stevenvallejo780@gmail.com