Diego Fernando Ángel Londoño
Verified Expert in Engineering
Full-stack Developer
Martínez, Buenos Aires Province, Argentina
Toptal member since May 20, 2021
Diego is a senior software engineer with over 9 years of experience in building back-end systems and platforms for startups and enterprise products. His work typically involves designing and operating services that coordinate multiple systems, data sources, and external APIs to support production workflows. Diego takes ownership of projects from early design through to production, emphasizing reliability, performance, and maintainable architectures as systems grow.
Portfolio
Experience
- Docker Compose - 9 years
- Node.js - 9 years
- Amazon Web Services (AWS) - 7 years
- TypeScript - 6 years
- Serverless Framework - 5 years
- GraphQL - 5 years
- MongoDB - 4 years
- React - 4 years
Preferred Environment
NeoVim Text Editor, Slack, Tmux, Docker, Docker Compose, Amazon Web Services (AWS), Unix
The most amazing...
...thing I've done is take a marketplace back end from 0 to 1, scaling it to handle thousands of applications monthly with a 3-5 minute application flow.
Work Experience
Senior Software Engineer
Proxet - General Catalyst
- Owned and shipped AI agents using MCP tools and RAG pipelines to automate research workflows, allowing investment teams to generate reports, retrieve portfolio data, and explore relationships between main entities through natural language.
- Led the development of a large-scale entity resolution system that consolidates people, companies, and roles across 8 heterogeneous sources into a canonical dataset with 98%+ matching accuracy and zero duplicates for verified identifiers.
- Built core back-end services and data models powering a relationship intelligence and portfolio platform used by investment teams to analyze entities networks, manage portfolio reports, and track notes and meetings across portfolio companies.
- Developed internal HR systems to automate recruiting workflows and employee management, developing back-end services and integrations to synchronize employee data across external HR platforms, eliminating time-consuming manual updates.
Senior Software Engineer
Zoolatech (Knock - RealPage)
- Owned and built conversational AI workflows across voice, chat, and email for the RealPage/Knock leasing platform, handling 100K+ prospect and resident conversations per month.
- Reduced average support conversation time from around 10–15 minutes to 5–10 minutes (35–50%) by redesigning conversation routing and expanding automated self-service flows, reducing human-handled conversations by roughly 30%.
- Cut p95 response times from 1+ minute to around 100-400ms by redesigning conversation handling and removing blocking service calls. Introduced caching and a routing service for voice, chat, and email, reducing live call abandonment by around 30.
- Led the design and implementation of an internal session viewer to debug production AI conversations, allowing engineers and the product team to inspect transcripts, triggers, and failures and jump directly to problematic segments.
Sr. Software Engineer (Founding Engineer)
Protege
- Joined at inception and built the back end and infrastructure from scratch to production for a marketplace connecting applicants with experts, powering application workflows, expert video reviews, and payments with payouts via Stripe.
- Scaled the platform to support around 5,000–10,000 applications per month and about 2,000 daily visits while maintaining under 1 second API latency and less than 2% application flow errors across payments and media processing.
- Built a media processing pipeline for expert review videos, validating uploads in the request path, and handling video processing asynchronously to keep the application flow fast.
- Designed a fast and reliable application flow, achieving under 2% error rates and enabling end-to-end application completion in about 2–3 minutes, reducing user drop-off and support requests.
Senior Node.js Developer | Tech Lead | Associate
Fizzmod (Janis)
- Built and evolved event-driven order orchestration handling 100,000+ orders/day, coordinating inventory, picking, and delivery across multiple logistics providers for major LATAM retailers, including Walmart, Jumbo, and Miniso.
- Created and maintained integrations with 8 logistics providers (DHL, Uber, FedEx, Andreani, etc.), coordinating picking, delivery scheduling, routing, and stock updates with under 50ms service execution and less than 200ms end-to-end latency.
- Led delivery across three teams (13 engineers total) spanning events infrastructure, delivery orchestration, and the Jumbo Argentina client while remaining hands-on in back-end development.
- Managed the dedicated team for the Jumbo Argentina client, delivering custom logistics and order-lifecycle features for one of the company’s largest retail partners.
Full-stack Developer
Cerantola
- Built features for an internal operations system used by staff to manage quotes and orders.
- Implemented back-end APIs and admin UI forms to automate manual workflows and improve data accuracy.
- Built internal tools that streamlined quoting and order workflows, reducing manual processing and helping operations staff complete daily tasks faster and with fewer errors.
Full-stack Developer
Inside
- Developed and maintained a website and admin tools for a retail store to manage products, orders, and inventory.
- Implemented back-end logic and database models for products, orders, and customers, integrating them with the admin UI.
- Helped strengthen and improve the platform they used to manage the company's inventory.
Experience
Janis Delivery Service
Education
Bachelor's Degree in Petroleum Engineering
Universidad Industrial de Santander - Bucaramanga, Colombia
Certifications
AWS Certified Developer – Associate
Amazon Web Services Training and Certification
Skills
Libraries/APIs
Node.js, OpenAPI, Vue 2, React
Tools
Docker Compose, Terraform, Dialogflow, Amazon Simple Queue Service (SQS), Amazon Simple Notification Service (SNS), AWS IAM, Amazon Cognito, BigQuery, Sentry, Apache Airflow
Languages
PHP, JavaScript, TypeScript, GraphQL, Python 3, Python
Frameworks
Serverless Framework, Express.js, JSON Web Tokens (JWT), NestJS, Django, Spark
Paradigms
REST, Scrum, Agile Software Development, Microservices
Platforms
AWS Lambda, Amazon Web Services (AWS), Docker, Unix, AWS IoT, Airbyte
Storage
MongoDB, PostgreSQL, MySQL, Redis, Amazon DynamoDB, Amazon S3 (AWS S3), Datadog, Google Cloud
Other
Back-end Development, Message Queues, Remote Team Leadership, Software Architecture, RESTful Microservices, Serverless, OpenAI, ECS, Amazon API Gateway, LangChain, Weaviate, Data Build Tool (dbt)
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