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CV · EXPERIENCE

Cristhian FonsecaCristhian Javier Delgado Fonseca

Technical Lead · AI agents in production · FinTech at scale on AWS

Colombia · Remote (CT/ET overlap)Open to: Remote Technical Lead / Senior AI Engineer roles with US teams · full-time or contract
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Client names are withheld under confidentiality agreements. I'm happy to share them — and references — during a hiring process.

Technical Lead and full-stack engineer with 5+ years building cloud-native FinTech and banking platforms. I lead engineering for a digital credit marketplace embedded in a major telecom's Super App — ~100K monthly active users inside a 45M-user ecosystem — and between 2022 and 2026 I built core banking modules for an enterprise banking client. I build AI systems that run in production — an MCP server the business uses to query live data, an autonomous triage agent, a multi-agent delivery pipeline — and I own the AWS underneath: I cut our cloud bill by 43% and trace every incident to root cause.

AT A GLANCE

  • 5+

    Years shipping to production (since 2021)

  • ~100K

    Monthly active users on my current platform

  • −43%

    AWS bill after the cost audit I led

  • 30×

    Faster bulk data export (638K rows in 21 s)

WORK HISTORY

May 2025 – Present

Full-time

Bogotá, Colombia

Current

Technical Lead · Prosperas

Credit marketplace inside a major telecom's Super App

  • Lead architecture and full-stack delivery of a cloud-native credit marketplace used by ~100K monthly active users within a 45M-user ecosystem.
  • Lead a cross-functional engineering team: technical standards, architecture patterns, code-review guidelines and a DevOps-first culture. Main technical interface with the partner and senior leadership.
  • Implemented user authentication with AWS Cognito and secret management with Secrets Manager across dev → staging → production pipelines, with CloudWatch monitoring and alerting.
  • Built a read-only MCP server that lets managers and analysts query production data in natural language. I found and fixed a 98.4% undercount at its root cause, and closed its security gaps under adversarial review.
  • Built an autonomous production-triage agent (headless Claude Code with the Sentry, Jira and Slack MCPs) that runs on weekdays under a strict no-commit contract.
  • Led an AWS cost audit across 17 regions that cut the monthly bill by 43%, with budgets, anomaly alerts and retention policies so the savings hold.
  • Replaced a managed BI service with charts-as-code (Angular, ECharts, FastAPI, Postgres materialized views) at exact parity with the legacy dashboards; bulk export became 30× faster.
  • Optimized analytical queries across 2M+ records and resolved production incidents to root cause: storage burst exhaustion, database locks, an orphaned queue, and WAF false positives.
AWS CDKLambdaRDS/PostgreSQLElastiCache/RedisS3API GatewayCognitoSecrets ManagerCloudWatchPythonFastAPIAngularTypeScriptClaude APIMCP

Nov 2024 – Mar 2025

Full-time · Remote

Lead Developer · ImkGlobal (Ingenieros de Marketing)

Apps for government-backed regional tourism services

  • Led a development team: technical decisions, architecture and sprint planning in an agile environment.
  • Built cross-platform mobile and web applications in Flutter for government-backed regional tourism services.
  • Bridged technical teams and non-technical stakeholders, turning business requirements into development tasks.
FlutterDartREST APIs

Oct 2022 – Aug 2026

Contract · Remote

Remote

Full-Stack Developer (Frontend consulting) · eSoluzion

Core banking modules for an enterprise banking client

  • Built and maintained Angular interfaces across multiple core banking modules.
  • Designed end-to-end modules in Java (Spring Boot) and Thymeleaf that meet the bank's code-quality and regulatory-compliance standards.
  • Remediated security vulnerabilities in a legacy Java codebase by replacing unsafe regex-based methods.
  • Delivered features with product owners and QA against business requirements.
  • Integrated an AI chat assistant into an internal credit-analysis application through the bank's corporate AI gateway, including enterprise authentication flows (Spring MVC, Thymeleaf).
AngularTypeScriptJavaSpring BootThymeleaf

Apr 2022 – Mar 2023

Full-time · Remote

Software Engineer · Dualboot Partners

Cloud services for a US-based car-rental platform

  • Designed and deployed AWS services for message delivery, notifications and operational workflows.
  • Built serverless architectures with AWS Lambda and Chalice, automating data flows and removing manual processing bottlenecks.
  • Configured high-availability infrastructure (EC2, Elastic Load Balancers, Route 53, API Gateway) and Python/Django services on PostgreSQL/MySQL with SES and SNS.
PythonDjangoAWS LambdaChaliceEC2ELBRoute 53API GatewaySESSNSPostgreSQLMySQL

May 2021 – Jun 2022

Full-time · Remote

Data Analyst / Java Developer / Full-Stack Developer · Accenture

A global bank's Colombian operation and a telecom operator

  • Built Java (Spring Boot) backend services on the bank's batch and online frameworks, plus full-stack features on the MEAN stack.
  • Built administrative dashboards (Google Apps Script, Data Studio) that helped recover a project running one year behind schedule.
  • Built Power BI dashboards integrating Oracle and MongoDB sources for real-time telecom incident statistics.
JavaSpring BootMEAN stackPower BIOracleMongoDBGoogle Apps ScriptData Studio
FOUNDER WORK

2026 – Present

Side project · Founder

Founder & Tech Lead · Aphrodite — AI companion marketplace

A marketplace where AI that actually knows each user fights loneliness. It runs several internal micro-economies, so the product and the business model are built together. Pre-launch; happy to walk through the code in an interview.

  • Founded and build, solo, Aphrodite, an AI companion marketplace: hexagonal architecture, two-tier conversational memory with crypto-shredding erasure, a pre-LLM safety gate, and signed idempotent payments.
  • Deliver with a multi-agent software factory (planner, coder and adversarial reviewer agents working from specs), backed by 3,000+ automated tests and rollback exercised in production.
TypeScriptNext.jsPostgreSQLpgvectorDockerTerraformCloudflareClaude Code
HOW I WORK
  • Measure before you execute. Before a destructive data operation I write down the expected numbers and rehearse on a copy of production; that rehearsal once caught 6 errors before they reached users.
  • Percentiles over averages. A cluster averaging 12.7% CPU looked oversized; its p99 was 97.5%. I kept it.
  • A merge to infrastructure is not a deploy. A fix merged weeks earlier had never reached the CDN. Now I verify the running artifact, not the pull request.
  • Monitor the outcome, not the mechanism. Every check was green while production ran a 38-day-old build. I added an ancestry gate and a staleness alarm.
  • An agent's report is a claim, not evidence. I use AI agents heavily, and every delivery goes through adversarial reviewer agents and a check against the real tree before it counts as done.
EDUCATION & CERTIFICATIONS

  • B.Eng. Systems Engineering

    Universidad Autónoma de Bucaramanga (UNAB) · 2016 – 2020

  • Technical Degree in Computer Systems

    SENA · 2014 – 2016

  • Claude Code in Action

    Anthropic · Feb 2026

  • AWS Partner: Accreditation (Technical)

    Amazon Web Services · Jul 2020

  • Neural Networks and Deep Learning

    deeplearning.ai / Coursera · Sep 2020

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