Ahmed AbdelHalim, Developer in Berlin, Germany
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Ahmed AbdelHalim

Verified Expert  in Engineering

Software Developer

Berlin, Germany
Toptal Member Since
August 6, 2014

Ahmed is a senior API-focused, back-end, and infrastructure developer with more than nine years of experience. He has over four years in infrastructure automation and DevOps with experience in security analysis and red teaming exploit-testing. An avid fan of automation, sustainability, design patterns, and clean code, Ahmed is always interested in deriving a better problem-solving method for challenging tasks and learning sensible new technologies and tools when the need arises.


Ansible, Terraform, Amazon Web Services (AWS), Docker, Vagrant, Makefile...
JSON, XML, PostgreSQL, Docker, Sidekiq, Ruby on Rails (RoR), Ruby
Priori Data GmbH
Google BigQuery, Bash, Ruby on Rails (RoR), Ruby




Preferred Environment

Git, Docker, Vagrant, Bash, Ruby on Rails (RoR), Vim Text Editor, MacOS

The most amazing...

...fun project I worked on was Conway's Game of Life terminal CLI in multiple languages.

Work Experience

Senior Developer/DevOps

2018 - 2021
  • Implemented infrastructure as code (IaC) for different projects using Terraform and Ansible.
  • Standardized the deployment process (and maintained the process documentation).
  • Built templates to provision infrastructure on different cloud providers and development stages.
  • Built standardized workflows, using CircleCI to automate deployments for internal and external projects.
  • Implemented and maintained the (Rails 5) JSON API serving our infographics portal.
  • Maintained more than 99% of the documentation coverage of the infographics portal API and more than 90% of the test coverage.
  • Worked with Docker to provide deliverables for some of our external projects.
  • Provided support and tutoring to work with our standard deployment workflows internally and externally.
  • Worked closely with our systems engineer to support various DevOps tasks.
  • Rewrote, maintained, and provisioned some of the data pipelines to adhere to better security standards.
Technologies: Ansible, Terraform, Amazon Web Services (AWS), Docker, Vagrant, Makefile, Ruby on Rails (RoR), PostgreSQL, Redis, MongoDB, MySQL, React, TypeScript, Next.js, Python, Bash, Git, Tmux, Sidekiq, CircleCI, Travis CI, Asana, Jira, Notion, DevOps

Senior Back-end Developer

2016 - 2018
  • Maintained the RESTful API used by admins and front-end.
  • Implemented and maintained the integration with Deutsche Bank.
  • Applied and maintained the integration with the Intercom CRM.
  • Executed and maintained the internal invoicing system.
  • Implemented the new authentication layer using JWT (RFC 7519).
  • Carried out the two-factor authentication (2FA) for user/client login.
  • Integrated other services like DocuSign, Postident, etc.
  • Implemented day-to-day business, marketing, and technical requirements.
Technologies: JSON, XML, PostgreSQL, Docker, Sidekiq, Ruby on Rails (RoR), Ruby

Full-stack Developer

2015 - 2016
Priori Data GmbH
  • Maintained the external Rails web (dashboard) app.
  • Optimized the scraping process of getting data from the Apple and Google Play stores.
  • Reimplemented the queueing and monitoring around the scrapers.
  • Migrated acquired data from different resources to Google BigQuery.
  • Maintained and provisioned different purpose VM instances on Google Cloud Platform, using Chef.
  • Reimplemented the “extract” step in the ETL process, using an API-based crawler instead of the PhantomJS browser.
Technologies: Google BigQuery, Bash, Ruby on Rails (RoR), Ruby

Back-end Developer

2013 - 2015
  • Reimplemented large portions of the API to follow better design patterns, such as the hexagonal architecture and pub/sub patterns.
  • Implemented the test suite for the API with 80% coverage and mutation testing.
  • Executed the events-booking feature via Stripe API.
  • Carried out caching for better API response times.
  • Maintained the Heroku stacks for staging and production.
Technologies: Stripe Payments, MongoDB, Memcached, Redis, Ruby on Rails (RoR)

Game of Life CLI

A repo that includes different implementations for Conway's Game of Life in various programming languages (currently in Ruby and Rust) as a command-line interface (CLI) to simulate a Game of Life cyclic and periodic boundary condition and animate the GoL universe on the terminal.


A Bash script that wraps features for adding and removing submodules to a Git project. It is mainly used to manage installing and removing of Vim plugins.


A Bash script for new users to protect against deleting important data via the "rm" command. The script uses the system trash instead of deleting the files completely.


A small CLI to show the exchange rates of EGP from twenty different banks in a cool terminal table

EGP Rates

A gem that scrapes the exchange rates of EGP from twenty different banks.
2005 - 2011

Bachelor's Degree in Computer Engineering

Arab Academy for Science and Technology - Alexandria, Egypt


Ruby on Rails API, GitHub API, Sidekiq, Google APIs, Facebook API, React


Codeship, Travis CI, Wercker, GitLab, GitHub, Terminal, Vim Text Editor, RSpec, Git, Basecamp, Vagrant, Ansible, Terraform, BigQuery, Makefile, Tmux, CircleCI, Asana, Jira, Notion


JSON Web Tokens (JWT), Ruby on Rails (RoR), Next.js


Ruby, Bash, XML, Python, TypeScript, Rust


Continuous Integration (CI), REST, Continuous Delivery (CD), Test-driven Development (TDD), Behavior-driven Development (BDD), Continuous Deployment, DevOps


Heroku, MacOS, Docker, Software Design Patterns, Amazon Web Services (AWS), Linux


JSON, PostgreSQL, Redis, MongoDB, NoSQL, Memcached, MySQL


APIs, Stripe Payments, Google BigQuery, SOAP, Big Data, Unix Shell Scripting

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