Jacob Heijligers, Developer in Bangkok, Thailand
Jacob is available for hire
Hire Jacob

Jacob Heijligers

Bio

Jacob is a software consultant with a master's degree in computer science and engineering from TU Delft and over 10 years of experience architecting and delivering complete systems rapidly. Skilled in Rust, Go, Java, Python, TypeScript, SQL, Next.js, React Native, Kubernetes, and cloud platforms, he has built over 10 production-grade products solo, including applications serving millions of users. Recognized for his adaptability and problem-solving, Jacob has won prizes in global competitions.

Portfolio

Stealth AI Startup
AI Agents, AI Tools, Claude, Claude Code, Testing, AI Testing...
Miljoenhuizen.nl
Rust, Python, TypeScript, PostgreSQL, Redis, Software Design, Node.js...
Somnox
Java, PostgreSQL, Amazon Web Services (AWS), Software Design, JavaScript...

Experience

  • SQL - 12 years
  • Java - 12 years
  • Linux - 12 years
  • Python - 10 years
  • Go - 6 years
  • Rust - 6 years
  • React - 5 years
  • React Native - 3 years

Preferred Environment

Linux, JetBrains IDE, GitHub, Kubernetes, PostgreSQL, Cloud

The most amazing...

...project I've developed is a housing platform, which I built from the ground up, including a high-performance Rust-powered data pipeline.

Work Experience

AI Engineer

2025 - PRESENT
Stealth AI Startup
  • Crafted fair, high-signal test suites from a complex Rust code editor for Frontier AI Labs.
  • Built difficult, real-world challenges from a modern Rust code editor to train and evaluate AI models.
  • Crafted code challenges from a C++ desktop graphics application, targeting challenging real-world scenarios for AI training through reinforcement learning.
Technologies: AI Agents, AI Tools, Claude, Claude Code, Testing, AI Testing, Large Language Models (LLMs), Rust, C++, Zed, Blender, Artificial Intelligence (AI), AI Integration, OpenAI, Anthropic, AI Chatbots, Agentic AI, Conversational Agent, Workflow Automation, Generative Artificial Intelligence (GenAI), AI-generated Code, AI Automation, Machine Learning, OpenAPI, AI Model Training, AI Prompts

Full-stack Developer

2020 - PRESENT
Miljoenhuizen.nl
  • Built a high-performance, parallel data ingestion pipeline in Rust to process large housing datasets efficiently.
  • Designed and optimized a complex PostgreSQL database to support high-performance queries at scale.
  • Architected the complete system, from data sanitization pipelines to a fast, production-ready website.
Technologies: Rust, Python, TypeScript, PostgreSQL, Redis, Software Design, Node.js, JavaScript, Security, Software Architecture, Architecture, CI/CD Pipelines, API Design, Cloud, GitHub, JetBrains IDE, Linux, Databases, Full-stack Development, User Experience (UX), User Interface (UI), ChatGPT, System Architecture, Payment APIs, Infrastructure, Identity & Access Management (IAM), CSS, HTML, REST APIs, DOM, API Integration, Website Data Scraping, Large Language Models (LLMs), Full-stack, APIs, AWS Cloud Architecture, Amazon Web Services (AWS), Amazon S3 (AWS S3), Docker, Web Services, Software Development, AI Tools, Front-end, Codex, OAuth, DevOps, AI Agents, Git, Claude Code, Scraping, Web Scraping, Antibot Bypasses, Mobile, WebView, Web Architecture, React Navigation, AI Chatbots, Agentic AI, Workflow Automation, Core Web Vitals, CSS3 Animation, Platform as a Service (PaaS), GitHub Actions, OpenAPI, Cloud Native, Cloud Architecture, Minimum Viable Product (MVP), Data Extraction, Containerization, Scalable Architecture, JSON, System Administration, API Architecture, Back-end Development, Front-end Development, PostGIS, Data Pipelines

Back-end Architect

2017 - PRESENT
Somnox
  • Architected and implemented the complete back end, including pipelines for collecting and processing IoT device data.
  • Configured GitHub Actions CI/CD pipelines to enable automated testing and seamless deployment to AWS.
  • Developed secure user management features, including OAuth implementation as both client and provider.
Technologies: Java, PostgreSQL, Amazon Web Services (AWS), Software Design, JavaScript, Security, Software Architecture, Architecture, Mobile App Development, Mobile Apps, CI/CD Pipelines, API Design, Cloud, GitHub, JetBrains IDE, Linux, Databases, System Architecture, Infrastructure, Identity & Access Management (IAM), CSS, HTML, REST APIs, DOM, API Integration, APIs, AWS Cloud Architecture, Mobile Development, Amazon S3 (AWS S3), Docker, Web Services, Software Development, Front-end, OAuth, DevOps, Git, Bluetooth, Algorithms, Mobile, WebView, Web Architecture, Dashboards, System Integration, Platform as a Service (PaaS), Amazon CloudFront, Amazon Route 53, GitHub Actions, SendGrid, API Gateways, Cloud Native, Cloud Architecture, API-first Development, Minimum Viable Product (MVP), Containerization, Scalable Architecture, JSON, System Administration, API Architecture, Back-end Development

Full-stack Developer

2014 - PRESENT
Chaser.nl
  • Developed and optimized a high-performance flight ticket search engine aggregating data from multiple providers.
  • Architected the website from the ground up, covering back end, front end, and deployment.
  • Engineered a cross-platform mobile app from the ground up using React Native for iOS and Android.
Technologies: Java, TypeScript, React Native, SQL, Redis, Software Design, Node.js, JavaScript, Security, Software Architecture, PHP, Architecture, Mobile App Development, Mobile Apps, CI/CD Pipelines, API Design, Cloud, JetBrains IDE, Linux, Databases, Full-stack Development, User Experience (UX), User Interface (UI), Claude, System Architecture, Infrastructure, Code Review, Code Auditing, Identity & Access Management (IAM), Backup & Recovery, CSS, HTML, REST APIs, DOM, API Integration, Website Data Scraping, Full-stack, APIs, AWS Cloud Architecture, Expo, Mobile Development, Ubuntu, Amazon Web Services (AWS), Amazon S3 (AWS S3), Docker, Web Services, Software Development, AI Tools, Front-end, DevOps, Git, iOS, SQLite, Scraping, Web Scraping, Antibot Bypasses, Mobile, WebView, Web Architecture, MySQL, CSS3 Animation, Platform as a Service (PaaS), PHP 8, jQuery, SCSS, API Gateways, Cloud Native, Cloud Architecture, Minimum Viable Product (MVP), Data Extraction, Containerization, Scalable Architecture, Hibernate, JSON, NoSQL, System Administration, API Architecture, Back-end Development, Front-end Development, Data Science

Full-stack Developer

2018 - 2025
Medialab
  • Remediated multiple security vulnerabilities, transforming the platform from an exploit-prone environment into a secure and resilient system.
  • Designed and implemented a scalable anti-spam system, significantly reducing abuse and enhancing the user experience.
  • Implemented a Pub/Sub-based broadcast service for platform-wide messaging, ensuring high throughput and reliable delivery.
Technologies: Java, Go, Kubernetes, Terraform, Pub/Sub, ScyllaDB, Cassandra, Redis, Software Design, Node.js, JavaScript, Security, Software Architecture, Architecture, Mobile App Development, Mobile Apps, CI/CD Pipelines, API Design, Cloud, GitHub, JetBrains IDE, Linux, Databases, Full-stack Development, ChatGPT, System Architecture, Infrastructure, Code Review, Code Auditing, Identity & Access Management (IAM), Backup & Recovery, CSS, HTML, REST APIs, DOM, API Integration, Large Language Models (LLMs), C++, Full-stack, APIs, AWS Cloud Architecture, Mobile Development, Amazon Web Services (AWS), AWS Lambda, Amazon S3 (AWS S3), Docker, Amazon Simple Queue Service (SQS), Web Services, Software Development, AI Tools, Front-end, OAuth, JSON Web Tokens (JWT), DevOps, Git, Google Cloud Platform (GCP), Leadership, SQLite, Algorithms, Mobile, WebView, Web Architecture, SDKs, Dashboards, Workflow Automation, System Integration, MySQL, Core Web Vitals, Jira, Distributed Architecture, Event-driven Architecture, Platform as a Service (PaaS), Amazon CloudFront, Amazon Route 53, Amazon Elastic Container Service (ECS), GitHub Actions, API Gateways, Microservices, Microservices Architecture, Cloud Native, Cloud Architecture, Minimum Viable Product (MVP), Containerization, Scalable Architecture, JSON, Large-scale Distributed Systems, NoSQL, System Administration, Event-driven Programming, Message Queues, Google Cloud, API Architecture, Back-end Development, Event-driven Systems, Front-end Development, Data Science, Data Pipelines

Experience

BetterThanMaps: High-performance Mapping Interface

https://betterthanmaps.com/
I reverse-engineered Google Maps' internal API to build a faster, cleaner front end in Next.js, hosted on Cloudflare's edge. The project delivers a more advanced and reliable way to find places, showcasing my deep understanding of undocumented systems and expertise in optimizing UI performance.

Ragebot: Scalable Anti-spam Chatbot

https://ragebot.net/
Ragebot evolved from a personal chatbot project into a platform serving millions of users on Kik. Its primary function was detecting and removing spam bots, built on a reverse-engineered protocol with an asynchronous Python back end. Operating in this adversarial environment, I developed creative solutions to scale the system and added features such as real-time chat, moderation tools, and optional AI-powered custom bots.

CloneMy.App: APK Duplication and Rebranding Tool

I built CloneMy.App, a tool that allows users to upload an Android APK and automatically generate a duplicate with a new package name. The system manages binary patching, signing, and delivery, enabling easy app rebranding or parallel installation without requiring the source code.

TON Trustless Bridge Challenge

https://contest.com/ton-trustless-bridge
Achieved a shared 2nd place in the global TON Trustless Bridge Challenge on contest.com, a highly competitive, Telegram-backed contest focused on advanced cryptography and smart contract engineering. Designed and implemented a secure cross-chain bridge solution involving trustless validation and contract logic, despite having no prior experience in this domain. Successfully navigated complex requirements around security, correctness, and decentralized execution to deliver a high-quality solution recognized among top global participants.

Education

2013 - 2021

Master's Degree in Computer Science and Engineering

Delft University of Technology - Delft, Netherlands

Skills

Libraries/APIs

Node.js, React, REST APIs, jQuery, OpenAPI, Playwright, React Navigation

Tools

GitHub, Expo, Codex, Git, WebView, Amazon CloudFront, Terraform, ChatGPT, Claude, Amazon Simple Queue Service (SQS), Claude Code, Jira, Amazon Elastic Container Service (ECS), SendGrid, AI Prompts, Zed, Blender

Languages

Java, Go, TypeScript, SQL, Rust, Python, PHP, JavaScript, CSS, HTML, PHP 8, SCSS, C, C++

Frameworks

React Native, Next.js, Tailwind CSS, JSON Web Tokens (JWT), Flask, Scrapy, Express.js, Hibernate

Paradigms

Mobile Development, DevOps, Web Architecture, Microservices, Microservices Architecture, API-first Development, API Architecture, Event-driven Architecture, Event-driven Programming, Testing

Platforms

Linux, Amazon Web Services (AWS), Docker, Google Cloud Platform (GCP), Mobile, Cloud Native, Kubernetes, Android, Ubuntu, AWS Lambda, iOS, Mapbox, Blockchain

Storage

PostgreSQL, Databases, Amazon S3 (AWS S3), SQLite, MySQL, JSON, Google Cloud, PostGIS, Redis, Cassandra, ScyllaDB, NoSQL, Data Pipelines

Other

Cloud, Software Engineering, Artificial Intelligence (AI), API Design, CI/CD Pipelines, Mobile Apps, Mobile App Development, Architecture, Software Architecture, Software Design, Full-stack Development, Chatbots, System Architecture, Infrastructure, API Integration, Website Data Scraping, Large Language Models (LLMs), Full-stack, APIs, AWS Cloud Architecture, Web Services, Software Development, AI Tools, Front-end, OAuth, AI Agents, Cryptography, Scraping, Web Scraping, Algorithms, Antibot Bypasses, SDKs, AI Chatbots, Agentic AI, Conversational Agent, Dashboards, Workflow Automation, System Integration, Core Web Vitals, Static Site Generators, Generative Artificial Intelligence (GenAI), AI-generated Code, Hash, CSS3 Animation, Distributed Architecture, Platform as a Service (PaaS), Amazon Route 53, GitHub Actions, API Gateways, Cloud Architecture, Minimum Viable Product (MVP), Data Extraction, Containerization, Scalable Architecture, Large-scale Distributed Systems, System Administration, Back-end Development, Front-end Development, JetBrains IDE, Computer Networking, Pub/Sub, Reverse Engineering, Cloudflare, Security, AI Integration, User Experience (UX), User Interface (UI), Payment APIs, Code Review, Code Auditing, Identity & Access Management (IAM), Backup & Recovery, DOM, Chrome Extensions, FastAPI, Cursor AI, Leadership, Bluetooth, OpenAI, WebSockets, Classification, AI Automation, Machine Learning, OpenAI GPT-4 API, Message Queues, Event-driven Systems, AI Model Training, Data Science, AI Testing, Anthropic, Web3, Smart Contracts, Distributed Software, Cryptocurrency, Zero-knowledge Proofs, Consensus Mechanism, Consensus Algorithms, Distributed Systems

Collaboration That Works

How to Work with Toptal

Toptal matches you directly with global industry experts from our network in hours—not weeks or months.

1

Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.
2

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.
3

Start your risk-free talent trial

Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.

Top talent is in high demand.

Start hiring