
Daniel Fonnegra Garcia
Verified Expert in Engineering
Software Engineer and Developer
Berlin, Germany
Toptal member since July 4, 2024
Daniel is a skilled software engineer with seven years of experience in various industries like IoT, mining, fintech, and streaming. He specializes in architecting scalable software in Python with FastAPI, SQLAlchemy, and PostgreSQL, combined with software design approaches like domain-driven design (DDD), CQRS, event sourcing, and hexagonal architecture. Daniel has deployed scalable apps to AWS for several years using services like Amazon EC2, Amazon S3, Amazon EKS, Route 53, and Amazon RDS.
Portfolio
Experience
- Python - 7 years
- PostgreSQL - 6 years
- Docker - 6 years
- Amazon Web Services (AWS) - 5 years
- FastAPI - 4 years
- SQLAlchemy - 4 years
- Software Architecture - 3 years
- Domain-driven Design (DDD) - 2 years
Preferred Environment
Python, FastAPI, SQLAlchemy, PostgreSQL, Vue, Kubernetes, Docker, Domain-driven Design (DDD), Hexagonal Architecture, Amazon Web Services (AWS)
The most amazing...
...thing I've developed is a web application to manage plans, dredging maps, and reports for Mineros SA, the biggest mining company in Colombia.
Work Experience
Senior Software Engineer
ESG Book
- Developed the platform's Go-based back end, enabling companies to publicly and privately disclose environmental, social, and governance (ESG) data and investors to view and score such data.
- Designed a framework mapping feature that enables companies to disclose information faster by prefilling part of the disclosure with publicly available or previously disclosed data.
- Wrote design documents with architectural decisions and models on several new features.
- Maintained a custom project for a private client that had over 200,000 users.
Back-end Engineer
DIZZBO
- Designed and implemented multiple microservices for a freight transport app using FastAPI and SQLAlchemy. Deployed them in an EKS Kubernetes cluster.
- Automated the creation of database users, roles, and permissions using PostgreSQL and Terraform.
- Built a project template for the microservices to boost the development and deployment process.
- Created a Helm charts template tailored to the infrastructure requirements of each microservice.
- Designed the authorization infrastructure for granular ACM between users and microservices.
- Developed communications microservices integrated with SendGrid for transport managers to use to control the orders via email.
Full-stack Engineer
castLabs
- Engineered the back- and front-end infrastructure for the Above venture by Touch and castLabs, focusing on a scalable web application that enables CSPs to generate video content for fast aircraft uploading.
- Coordinated the use of multiple tools, including Amazon ECS, Amazon Elastic Container Registry (ECR), Amazon RDS, AWS ALB, Amazon Virtual Private Cloud (VPC), Amazon Route 53, Amazon CloudFront, AWS CodePipeline, CDK, Django, and Vue.
- Managed a three-person team composed of two full-stack engineers and one front-end engineer.
Software Engineer
Ubidots
- Designed a data analysis module for user-driven statistics on time series, model execution, and regular report generation.
- Developed an algorithm to minimize query loads on a Cassandra database and regulate RedBeat task frequency, cutting server overload from 700% to 20%.
- Implemented a scalable dataset service allowing users to store large datasets in Amazon S3, optimized for rapid reading and filtering, resulting in an Apache Parquet file managed by Dask.
Quantitative Analysts
Ultraserfinco
- Constructed a fixed rent index categorized by reference rate, class, rating, term, and currency.
- Implemented a Black-Litterman model for optimizing fixed rent portfolios.
- Implementated a factor model to optimize equity portfolios.
- Developed a desktop app that facilitates portfolio simulation and backtesting, profit and risk estimation, financial data access, company strategy integration, and data exportation.
Experience
Content Management System (CMS) for Metrofibre
Project Management App for Ecoplan Thiede
AutoCAD Plan Generation for Mineros SA
I architected and developed a serverless website within the AWS ecosystem. The user interface is built on the Vue framework and leveraged Amazon CloudFront for deployment. Python forms the core of the back end, interacting with a DynamoDB database, and is deployed using AWS Lambda with API Gateway for RESTful API services. Amazon Cognito provides secure identity management.
This deployment via AWS resulted in an extremely cost-efficient and maintainable web application that can incorporate future projects on the same platform.
Trading Robot for Mean Reversion Strategies
Bare Metal Kubernetes Setup for NFT's Website
Bitrix Whatsapp Integration
The app orchestrates AWS Lambda, AWS SQS, and the EC2 instance to avoid message loss and increase availability.
Fixing Web Application in AWS App Runner
• Bring the app back up.
• Onboard a new tenant to the platform and document it.
The application was successfully fixed, and a deep dive was required to figure out how to onboard the users.
GeoCMS
Senior Back-end Developer to Help Fixing and Stabilizing an Existing Web App
http://dwcreative.comCommercial Demand Forecasting Platform for Nuvant
Cortex: Personal AI-native Organization System
I built a Mac launchd daemon using Bun and TypeScript to run read-only Downloads and Gmail collectors, while a Vercel-hosted Next.js 16 web app served as the DB access boundary. Used Neon serverless PostgreSQL with pgvector (HNSW, halfvec 512-dim embeddings) via Prisma 7. I also implemented a client-driven two-phase ingest flow with reserve, upload, and confirm stages using Drive resumable uploads.
Heavy LLM work, including classification and chunking, was offloaded to Claude Code CLI on the Max subscription, while Anthropic Haiku handled Q&A synthesis. I integrated Clerk for authentication, and Langfuse tracing across classify, chunk, embed, and ask calls. I shipped seven phases in three days while keeping total runtime costs around $5–10 per month at personal usage volume.
Education
Master's Degree in Informatics and Applied Mathematics
National University of Colombia - Medellin, Colombia
Bachelor's Degree in Physics
National University of Colombia - Medellin, Colombia
Certifications
AWS Solutions Architect Professional
Amazon Web Services
Skills
Libraries/APIs
SQLAlchemy, REST APIs, Sockets, Django ORM, API Development, Python API, Vue, React, WhatsApp API, Auth, Open APIs, Claude API, Node.js
Tools
AWS Cloud Development Kit (CDK), Amazon Elastic Container Registry (ECR), Terraform, Amazon Elastic Container Service (ECS), Celery, NGINX, AWS CloudTrail, Bloomberg, AutoCAD, Amazon Virtual Private Cloud (VPC), AWS Step Functions, Amazon CloudWatch, GIS, Prisma
Languages
Python, Go, SQL, JavaScript, C#.NET, TypeScript
Frameworks
Django, Vuetify, Django REST Framework, Flask, Flutter, AWS HA, Swagger, AngularJS, Next.js, Tailwind CSS
Paradigms
Database Design, Real-time Systems, DevOps, Microservices
Platforms
Docker, Amazon EC2, AWS Lambda, Amazon Web Services (AWS), Kubernetes, Mobile, Google Cloud Platform (GCP), Apache Kafka, Azure, AWS NLB, Vercel
Storage
PostgreSQL, Amazon S3 (AWS S3), Databases, Redis, PostgreSQL 10, PostGIS
Other
FastAPI, Domain-driven Design (DDD), Hexagonal Architecture, Infrastructure as Code (IaC), HTTP, Trading Bots, Architecture, Full-stack, Software Architecture, Software Design, Front-end, APIs, API Integration, Automated Trading Software, Back-end Development, Code Review, Debugging, Software as a Service (SaaS), CI/CD Pipelines, AWS Cloud Architecture, Full-stack Development, Machine Learning, WebSockets, Webhooks, Telnet Protocol, Mobile Apps, Transactions, Artificial Intelligence (AI), Quantum Mechanics, Stochastic Modeling, DXF, Bitrix24, Amazon RDS, Amazon Route 53, Scalable Architecture, Amazon API Gateway, Location Tracking, Relational Database Services (RDS), Google BigQuery, Time Series Forecasting, Pgvector, RAG Systems, Vector Search, Large Language Models (LLMs)
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