Philosopher & Software Engineer

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.

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PRÁXISBACKENDAIFRONTENDDEVOPSARCHITECTURE
10+
years building software in real production
7
coordinated services in the Agora platform
BYOK
AI agent engine with a client-configurable LLM provider
AES-256
encrypted secrets; Zod contracts and a custom MCP server
  • Where I have built systems
  • Humanizar Systems
  • Finca Directa S.A.S
  • Indie Levels Studio S.A.S
  • Critertec
  • Soy Digital — Dominican Government (INDOTEL)

Track record

Over a decade building and operating production systems — for private companies and the public sector. These are the roles behind every delivery.

  1. 2022 — present

    Humanizar Systems

    Founder / Lead Developer

    Multi-tenant SaaS ecosystem in production: e-commerce, POS with DIAN electronic invoicing, credit fintech and WhatsApp messaging, integrated through a central hub.

  2. 2021 — present

    Finca Directa S.A.S

    CTO / Head of Systems

    Technical leadership of a multi-tenant platform: OMS, RPA business automation, invoice OCR and CRM sync. Services agreement.

  3. 2021 — present

    Indie Levels Studio S.A.S

    Backend Developer

    Backend development on scalable services and production APIs. Fixed-term contract.

  4. Nov 2024 — Jun 2026

    Critertec

    Systems Administrator

    Real production operations: Linux, networking and VPN, observability (SIEM), GCP and Docker. Fixed-term contract, ended 2026.

  5. Nov 2024 — Jun 2026 · via Critertec

    Soy Digital — Dominican Government (INDOTEL)

    Frontend Developer

    Government project via Critertec: offline-first frontend with IndexedDB, data synchronisation and analytics for digital-enablement audit.

Platform case study

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.

  • Independent services: Next.js frontend, Cloud Run backend, real-time hub and workers in containers.
  • Agentic engine with an extensible tool registry (git, kanban, shell, formal logic) and a client-configurable LLM provider (BYOK).
  • Docker workers running real Linux terminals with HMAC-secured synchronisation.
  • Verifiable design: typed contracts with Zod, AES-256-GCM encrypted secrets, a custom MCP server. Deployed and running.
See Agora live

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 · view

Graf

Multi-store e-commerce (Humanizar): catalogue, real-time inventory, checkout and payment gateway. NestJS + PostgreSQL + Next.js, in production.

Live · view

Sinergia POS

Point of sale with DIAN electronic invoicing, cash drawer, taxes and multiple gateways. PWA that keeps selling without internet.

Live · view

FIAR

Credit fintech (Humanizar): loan portfolio, recurring payments and analytics dashboard on NestJS + TypeORM + Mercado Pago, in production.

Live · view

Cristina CMS

Custom editorial CMS in Next.js + Neon Postgres, foundation for media outlets and corporate blogs.

Live · view

Soy Digital

Systems for the Dominican Government (INDOTEL, via Critertec): offline-first frontend with sync and data analytics for digital-enablement audit.

Live · view

What 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.

From $400 USD + $30–60/moI'm interested

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.

From $300 USDI'm interested

AI photo upscaling and restoration

Blurry or low-resolution images come out sharp and professional, in batch. Catalogue ready to sell within 48 h.

From $150 USDI'm interested

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.

$200–500 USDI'm interested

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.

$35 USD/h or fixed scopeI'm interested

Landing page or conversion-focused website

Next.js sites, fast, SEO-ready and built to sell. Instant load and ready to receive clients.

From $500 USDI'm interested

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.

Write to me now

Prefer email? stevenvallejo780@gmail.com