~/hamza

Cairo, Egypt · Working remote

Hamza Hassanain

Founding Software Engineer @ Repovive YC F'26

I scale distributed backend systems and cloud infrastructure: I built the contest judge and core systems behind a 10,000+ user competitive-programming platform. I'm an AWS Certified Solutions Architect – Associate, a 3× ACPC Finalist, and I contribute upstream to LLVM/Clang, GitLab and Apple Swift NIO.

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Portrait of Hamza Hassanain

01. About

Cloud & Full-Stack Engineer · AWS Certified Solutions Architect – Associate. I build scalable web systems on AWS, and I go deep enough to understand every layer beneath them.

At Repovive, a Y Combinator-backed science expert community, I engineer the infrastructure behind a competitive-programming platform: a distributed, sandboxed judge, real-time contest tooling, and AI-assisted problem authoring. The work sits where hard algorithms meet web infrastructure that has to stay fast and cheap under load.

Competitive programming & mentorship. 3× ACPC Finalist. I've authored ECPC-qualifier and JCPC problems and mentored 100+ trainees from basic syntax to regional-level performance. I also coach engineers privately for Big-Tech interviews with tailored curricula and live problem-solving.

Systems & open source: I learn a system by building it. I contribute to the tools I depend on: LLVM/Clang (constexpr X86 intrinsics, ARM codegen), GitLab (Go SDK & Terraform provider) and Apple Swift NIO. I've also built the fundamentals from scratch, including a Red-Black-Tree memory allocator (HAllocator), a POSIX shell (hesh) and an epoll-driven C++ web framework (cppress).

02. Experience

Founding Software Engineer · Repovive YC F'26

Full-time · United States (Remote) · – Present · 11 mos

Repovive is a Y Combinator-backed science expert community where experts solve unsolved scientific problems, starting with theoretical computer science and math proof reasoning. It hosts live programming and math contests and has grown to 10,000+ users.

  • Joined as the first engineer and built the core systems from the early days through YC.
  • Onboarded and supported new engineers, senior hires included, guiding them through the codebase and projects; mentored junior programmers to improve their first code deliveries.
  • Moved CI to Vercel when the GitHub Actions quota ran out: one fail-fast pipeline (format → typecheck → test → build) with no production secrets.
  • Tracked down live-contest outages using Claude Code, MCP servers, PostHog and log analysis, then shipped the fixes.

Repovive Judge & Contest Infrastructure

Led design and build of the distributed judge (judge1, on Judge0): multi-language compilation, isolated sandboxes, and agentic test generation.

  • Scaled submissions 10× (50 → 500+ concurrent) with a Redis-backed async pipeline.
  • Cut infra cost 95% ($600 → $25/mo) by moving off serverless to Docker / Nginx / Redis.
  • Sandboxed 20+ languages in resource-limited Docker images.
  • Redesigned the DB layer for 50 MB+ contest test cases.

Repovive AI Interviewer Platform

Co-built a real-time voice AI interviewer for coding, recruiter and behavioral interviews, used for both practice and B2B screening.

  • Built "Kevin", the AI coding interviewer: 6 LLM tools, live Monaco editor reads, and judge-backed code runs.
  • Made interviewers markdown-defined and versioned, so admins add new ones without code changes.
  • Launched B2B screening: single-use invite links, auto-grading, and a partner ranking dashboard.
  • Hardened WebRTC voice turn-taking (1s to first word) across 7 LLM providers.
  • Shipped credit-based monetization with free attempts and auto-refunds.

Repovive Build v2: AI Problem-Authoring IDE

Co-founded a real-time collaborative IDE for competitive-programming problem setting, backed by autonomous agent pipelines.

  • Built an event-driven agent workflow with 28 tools and streaming turns.
  • Secured agent actions with execution locks and ~1s atomic cancellation.
  • Kept 10-minute streaming agent sessions stable.
  • Scaled concurrent server capacity 10× for automated test runs.
  • TypeScript
  • Node.js
  • Next.js
  • React
  • Judge0
  • Docker
  • Nginx
  • Redis
  • MongoDB
  • PostgreSQL
  • WebSockets
  • LiveKit
  • WebRTC
  • LLM agents
  • AWS
  • DigitalOcean
  • Vercel
  • PostHog
  • CI/CD

Problem Solving Instructor · Coach Academy

Freelance · Cairo, Egypt (Remote) · – · 1 yr 4 mos

  • Mentored hundreds of learners across skill levels, from complete beginners to ACPC-level competitive programmers.
  • Guided experienced software engineers through advanced problem-solving techniques to succeed in Big Tech coding interviews.
  • Designed and delivered customized programming curricula for university students.
  • Ran mock contests, mock interviews, problem discussions and strategy sessions to sharpen algorithmic thinking and interview performance.
  • Problem Solving
  • C++
  • Mentoring
  • Analytical Skills
  • Software Development
  • Team Work

03. Open Source Contributions

Every link below is a merged pull or merge request, described by what the diff actually does.

GitLab 11 merged MRs · 3 gitlab-org projects

Go SDK · client-go

!2692Slack integration: structs + GetGroupSlackSettings / SetGroupSlackSettings / DisableGroupSlack
!2691Discord / Telegram / Mattermost / Matrix / Google Chat structs + read-only GetGroup*Settings
!2679Microsoft Teams integration structs + typed return; fixed the microsoft-teams endpoint path
!2677Jira integration structs + typed GetGroupJiraSettings return
!2675Group Mattermost notifications + slash-commands: structs and Get / Set / Delete
!2670Harbor integration structs + typed GetGroupHarborSettings return

Terraform provider

!2909New gitlab_group_integration_mattermost resource (Plugin-Framework CRUD + acceptance test)
!2881New gitlab_group_integration_harbor resource (CRUD + import + acceptance test)
!2852Group SAML identity attribute on the gitlab_group_membership data source

GitLab monorepo

!221163Ruby: Gitlab::Json.parse → safe_parse in the discussions-diff highlight cache
!221158Vue: require-name-property compliance across deployment UI components

LLVM / Clang compiler codegen & tooling

#169980X86 / Clang constexpr evaluation of cvtpd2ps intrinsics
#178885AArch64 Convert CLS intrinsics to the generic ISD::CTLS node
#178430ARM Replace manual CLS expansion with ISD::CTLS
#173473LLDB SWIG Python-extension tests for SBTarget

Apple Swift NIO event-driven networking

#3410Idempotent directory creation in NIOFileSystem

04. Featured Projects

☁️ Cloud, full-stack & infrastructure

CP Judge — AWS Reference Architecture

A full AWS reference architecture for a contest judge (Manara AWS SAA capstone). Judge0 isolate workers run on ECS-on-EC2, a stateless orchestrator runs on Fargate, and a Spot mixed-instance ASG scales on queue depth. Post-round cheating detection uses Step Functions, AWS Batch, Lambda + Bedrock and Athena. Includes 7 architecture views and 9 documented design decisions.

  • AWS
  • ECS
  • Fargate
  • Step Functions
  • Bedrock
  • Well-Architected

Distributed Code Runner

A shared-nothing distributed code-execution platform: a Next.js client, an API gateway, and a sandboxed Judge0 cluster behind a managed load balancer, with a Redis job queue, all behind a Caddy reverse proxy.

  • TypeScript
  • Next.js
  • Express
  • Docker
  • Judge0
  • Redis

SigmaLoop — Autonomous AI Tutor live ↗

Graduation project. An on-demand AI tutor that generates whole programming-and-math curricula: courses, lessons and challenges. Code is graded in a Judge0 sandbox, math proofs by a confidence-scored LLM, and hints come from a self-fine-tuned Qwen2.5-Coder-7B. Led backend & DevOps for an 8-person team and owned all CI/CD and AWS deployments.

  • React 19
  • Node / Express
  • Judge0
  • LLMs
  • AWS
  • CI/CD

Polyman CLI ★ 37

A TypeScript CLI that automates the Codeforces Polygon workflow for problem setters: create, generate tests, validate and verify problems, then sync them to Polygon over its API without leaving the terminal. Published on npm, with docs.

  • TypeScript
  • Node.js
  • CLI
  • npm
  • Codeforces

🔩 Systems, built from scratch to learn the fundamentals

HAllocator docs ↗

An STL-compatible C++23 memory allocator: Red-Black-Tree best-fit search in O(log n) with free-block coalescing, covered by GoogleTest and documented with Doxygen.

  • C++23
  • RB-Tree
  • GoogleTest
  • CMake

hesh

A functional Unix shell in C++23 with process control, pipes, stdout/stderr redirection (> >> 2> &>), quoting, history, tab completion via GNU Readline, and an agnoster-style prompt.

  • C++23
  • POSIX
  • syscalls
  • Readline

AES-256-GCM, from scratch

An educational pure-Python AES-256-GCM implementation with an interactive GUI that shows every encryption and decryption step, a Diffie-Hellman key exchange, and attack simulations that show what GCM does and doesn't protect against.

  • Python
  • Cryptography
  • GUI

🏆 Competitive programming resources

CP Templates ★ 21

The data-structure and algorithm templates I use in contests, shared for others to use.

  • C++
  • DSA

05. All Repositories

Every public repository on github.com/HamzaHassanain. Star counts refresh live from the GitHub API.

GitHub contribution chart for HamzaHassanain

5,279 contributions in the last year

06. Competitive Programming

ICPC

  • ICPC ACPC: 3× Finalist (2024, 2025, 2026), top 250 across the Africa & Arab region. icpc.global ↗
  • ICPC ECPC: 17th of ~500 teams (2024).
  • Problem author, 2025 ICPC Jordanian Collegiate Programming Contest (JCPC): wrote G. Queries On Strings.
  • Problem author, Repovive Standard Round 3: wrote F. Graph Tiling.
  • Authored problems for ECPC qualifications and other subregional contests.

Online judges

Codeforces ratings update live from the Codeforces API.

I also solve on NeetCode and LeetCode, and I coach engineers one-on-one for Big-Tech interviews.

07. Volunteering & Teaching

  1. Problem Setter & Instructor · ICPC Suez Canal University Community

    Education · – · 2 yrs 1 mo

    • Designed and authored algorithmic problems at a range of difficulty levels for ECPC qualifications and other subregional contests, working toward varied, clear problems and balanced contest structure.
    • Mentored and instructed trainees and ran sessions at several levels, teaching problem-solving, data structures and algorithms. Took 100+ trainees from basic syntax toward regional-level performance.
    • Prepared local programming contests so trainees could test their understanding of each topic.

  2. Course Instructor · DevS (ديفز)

    Education · – · 10 mos

    • Assembled a 5-member team, each member owning a different part of delivering a problem-solving course.
    • Prepared a 6-month problem-solving curriculum from beginner to intermediate level.
    • Ran sessions and helped trainees understand the material and get the most out of the course.

  3. Back-End Developer · ICPC Suez Canal University Community

    Education · – · 4 mos

    • Worked with front-end and back-end developers on a web app for the ICPC-SCU community. It helped the HR, Media and Logistics teams manage trainee registration across levels 0/1/2, event sign-ups, and housing and transport for ECPC.
    • Integrated the Codeforces API to validate and regularly refresh trainees' Codeforces-linked data, such as handles.

08. Education & Certifications

Suez Canal University

Bachelor's degree, Computer and Information Sciences

– · Grade: Very Good

Activities & societies

  • ECPC
  • Arab & Africa Programming Championship
  • ICPC SCU Community
  • DevS Community
  • GDSC

Graduation project: SigmaLoop, Autonomous AI Tutor & Curriculum Engine

09. Technical Writing

I write about systems programming and engineering on dev.to/hamzahassanain0.

10. Skills

Cloud & DevOps

  • AWS (SAA)
  • Docker
  • Nginx
  • Redis
  • Terraform
  • GitHub Actions
  • CI/CD
  • DigitalOcean
  • Vercel
  • Linux

Backend & Full-Stack

  • TypeScript
  • Node.js
  • Express
  • Next.js
  • React
  • MongoDB
  • PostgreSQL
  • REST APIs
  • WebSockets
  • Yjs (CRDTs)
  • Monaco
  • LiveKit

Languages & Systems

  • C++ (17/23)
  • Go
  • Rust
  • Python
  • SQL
  • Swift
  • System Design
  • Distributed Systems
  • Message Queues
  • LLVM / Clang
  • CMake

Let's build something fast & cheap under load.

Hiring, collaborating, or preparing for interviews? My inbox is open.

hamzahassanain067@gmail.com