
Hafiz Haseeb Ahmed
Verified Expert in Engineering
Full-stack Developer
Bahawalpur, Punjab, Pakistan
Toptal member since June 7, 2022
Hafiz is a full-stack developer with more than four years of experience developing robust applications for high-volume businesses in an agile environment. He is a problem-solving team player with a can-do attitude and phenomenal communication skills. Hafiz has been working as a remote independent contractor with companies all over the globe.
Portfolio
Experience
- JavaScript - 4 years
- Django - 4 years
- Python - 4 years
- Bootstrap - 3 years
- Data Structures - 3 years
- Algorithms - 3 years
- WebSockets - 2 years
- IT Project Management - 2 years
Preferred Environment
Windows, PyCharm, Next.js, React, TypeScript
The most amazing...
...thing I've developed is a web app for Hovertise to manage and communicate with IoT-connected screens on car tops.
Work Experience
AI Trainer and Technical Evaluator
Revelo
- Evaluated full-stack TypeScript and React applications by testing user flows, checking implementation quality, and identifying correctness, UI, and production-readiness issues.
- Generated realistic interaction data for large language model (LLM) training by guiding coding agents through multi-step web application tasks and reviewing their behavioral patterns.
- Reviewed model outputs across logic, error handling, modularity, interface design, documentation, and verification discipline to improve training signal quality.
- Validated Docker-based development workflows by checking repository setup, build behavior, test execution, and final project readiness before submission.
- Assessed AI-generated code for common failure modes such as hallucinated APIs, incomplete implementation, overscoping, weak verification, and poor file organization.
- Created structured evaluation feedback with clear pros, cons, behavioral issue codes, and preference justifications for side-by-side model response comparisons.
- Tested end-to-end app behavior, including authentication, CRUD flows, persistence, front-end/back-end integration, loading states, validation, and error handling.
- Worked within Linux-style developer environments using VS Code, Git, Docker, terminal tooling, and repository-level debugging to complete technical evaluation tasks.
- Improved LLM training datasets by producing high-quality human feedback focused on practical software engineering, debugging, and production-readiness signals.
Python Trainer
OpenAI
- Spearheaded the initial Python training efforts for ChatGPT at OpenAI, contributing foundational knowledge and techniques that enabled its successful public launch in November 2022.
- Developed and integrated custom plugins to expand ChatGPT’s domain coverage, improving real-time response accuracy and enhancing user experience across financial, healthcare, and developer-focused APIs.
- Collaborated with AI researchers and product teams to optimize training workflows, resulting in a measurable 25% improvement in model performance and response quality across key benchmarks.
Director of Technologies and People
Boxeyi.com
- Initialized and managed the Xtriven app for drivers to earn more by advertising their vehicles to local advertisers.
- Streamlined the team's work and design using Figma, Trello, and Cliq.
- Interviewed and hired new developers for the company.
Product Engineer
Boxeyi.com
- Developed a web app that communicates with IoT-connected screens, records location data, and can play different advertisement pictures or videos based on the location.
- Designed a layout and workflow using Figma and Trello to manage and assign tasks.
- Automated the company's different operations and designed a portal for the salespeople.
Django Developer
Thinkgroupy
- Participated in developing a platform for freelancers to get projects and for organizations to get skillful developers from all around the globe.
- Introduced a feature for real-time messaging and video calls.
- Launched a web app that got attention from large organizations within the country.
Django Developer
Taha Solution
- Developed a Python Django web app to help people earn by making networks by each person referring another person so that the whole tree network benefits from each newly registered user.
- Collaborated with other team members to manage the overall web app and introduce new ideas, which were later converted into features.
- Handled deployment of the web app in the production environment.
Experience
Web App for Hovertise
Web App for Thinkgroupy
Web App PyNetworking
Smart Tourism Web App
Education
Bachelor's Degree in Computer Science
National University of Computer and Emerging Sciences - Lahore, Pakistan
Skills
Libraries/APIs
React, REST APIs, Node.js
Tools
NGINX, GitLab, PyCharm, Git
Languages
Python, JavaScript, CSS, HTML, HTML5, TypeScript, GraphQL, Java, Rust, Python 3, C++
Frameworks
Django, Next.js, Tailwind CSS, Bootstrap
Platforms
Google Cloud Platform (GCP), Amazon Web Services (AWS), Linux, Windows, Blockchain, Docker, Visual Studio Code (VS Code)
Paradigms
DevOps, REST
Storage
PostgreSQL, Relational Databases, Redis
Industry Expertise
Cybersecurity
Other
Full-stack, Data Extraction, Minimum Viable Product (MVP), Large Language Models (LLMs), AI Model Training, Debugging, WebSockets, Web App Development, APIs, Software Architecture, Artificial Intelligence (AI), Cloud Infrastructure, IT Project Management, Algorithms, Programming, Data Structures, Professionalism, Web Development, Internet of Things (IoT), Video Calling, Machine Learning, Data Science, Embedded Systems, LLM Evaluations, Data Annotation, Full-stack Development, Full-Stack Web App Evaluation, Code Review, Quality Assurance (QA), Behavioral Data Evaluation
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
Share your needs
Choose your talent
Start your risk-free talent trial
Top talent is in high demand.
Start hiring