Software engineer

Ahmad
Saleh

Software engineer · architecture · reliability

Four years shipping production systems and APIs — clean architecture, practical performance, and systems that stay dependable under load.

Download CV

01 · Focus

Reliable APIs

Production backends with clear contracts, solid debugging habits, and maintainable architecture.

02

Data & Search

Pipelines, document modeling, and indexing workflows that keep source systems and search aligned.

03

Performance

Query and runtime fixes grounded in real workloads — including large Oracle and Cassandra datasets.

runtime.log

info query.optimize latency 2h → 3s

ok opensearch.index sync=aligned

info deploy.ready env=production_

4+

Years shipping

99.9%

Query win

5+

Major projects

20

Engineer team

▸C / C++▸Java▸Spring Boot▸Oracle▸Cassandra▸OpenSearch▸AWS▸REST APIs▸System Design▸Production Debugging

About

Built for systems that stay up

I'm a software engineer with 4 years at Progineer Technologies — high-performance C backends, stability, efficiency, and correctness.

At Progineer I work deeply with Oracle, Cassandra, and OpenSearch — modeling, query optimization, and large production datasets. I also debug incidents, read logs, and untangle on-prem deployment issues.

Java, Spring Boot, REST APIs, and secure auth come from Bloom, my personal venue-booking platform. Enterprise reality at work: long-lived codebases, strict requirements, and cross-functional teams. I optimize for reliability and maintainability — not demos.

Education

Bachelor of Computer Science

An-Najah National University

Nablus · 09/2018 – 06/2022

Languages

ArabicNative
EnglishFluent

01

Production-first

Reliability over shortcuts — production incidents, runtime debugging, and correctness in long-lived enterprise systems.

02

System engineering

Performance-critical components, bottlenecks, deployments, and how systems behave under real load.

03

Database depth

Oracle schema/SQL optimization and Cassandra modeling across large production datasets.

Skills

Tools I reach for

Core Backend

01

Low-level and language foundations I use when latency and memory actually matter.

CC++JavaMemory ManagementPerformance Optimization

Databases

02
Oracle SQLCassandra NoSQLMongoDBMySQLData ModelingQuery Optimization

Backend Frameworks

03
Spring BootSpring SecurityJPA/HibernateRESTful APIs

Cloud & Infrastructure

04
AWS EC2AWS S3ALBAuto ScalingLaunch TemplatesVPC NetworkingNAT GatewayAWS Secrets ManagerLinuxSystem Architecture

Search & Data

05
Search IndexingIndexing Data GenerationData PipelinesDocument Modeling

DevOps & Tools

06
MavenGitProduction DebuggingLog AnalysisSystem Design
◆memory-safe paths◆index design◆query plans◆incident response◆API contracts◆search documents◆AWS networking◆log forensics

Projects

Selected work

01 · Project

Bloom – Venue Booking Platform

Personal Project
Client
ALB
Spring API
MongoDB
S3

Problem

Venue booking platforms need to handle complex reservation logic (full-day, time-based, event-based), ensure data consistency across concurrent bookings, and provide secure multi-tenant access with role-based permissions.

Solution

Built a production-ready Spring Boot REST API with clean layered architecture, implementing robust booking workflows, JWT authentication with refresh tokens, and database-driven multi-language support. Evolved the deployment into a scalable AWS architecture using ALB, Auto Scaling Groups with Launch Templates, VPC networking (public/private subnets, NAT Gateway), and AWS Secrets Manager for secure configuration.

View on GitHub →

Tech stack

Backend

JavaSpring BootSpring Security

Database

MongoDB

Infrastructure

AWS EC2AWS S3ALBAuto ScalingLaunch Templates

Networking

VPCPublic/Private SubnetsNAT Gateway

Security

AWS Secrets Manager

Integration

FirebaseOpenAI API

Documentation

Swagger/OpenAPI

Role

  • •Architected and implemented the entire backend system using clean architecture principles (Controllers → Services → Repositories)
  • •Designed and implemented JWT-based authentication system with refresh token rotation and role-based access control
  • •Built generic ownership validation framework ensuring users can only modify their own resources
  • •Designed MongoDB schemas optimized for booking queries with proper indexing strategies
  • •Implemented multi-language support system with database-driven translations (EN/AR/HE)
  • •Configured ALB and Auto Scaling Groups with Launch Templates for elastic, highly available backend deployment
  • •Designed VPC with public/private subnets and NAT Gateway for secure network segmentation and outbound access
  • •Integrated AWS Secrets Manager for credentials and configuration, and AWS S3 for media storage
  • •Integrated OpenAI API for chatbot functionality and maintained production monitoring and debugging workflows

Architecture

Layered architecture with separation of concerns: REST controllers handle HTTP requests, service layer contains business logic, repository layer manages data access. AWS infrastructure uses ALB in front of Auto Scaling Groups backed by Launch Templates, with application instances in private subnets and NAT Gateway for controlled outbound traffic. Secrets and credentials are managed through AWS Secrets Manager. MongoDB supports flexible schema design for multiple booking models.

Impact

Successfully handles complex booking scenarios with data consistency guarantees and secure multi-tenant access. The AWS architecture supports horizontal scaling, improved availability, and production-grade security patterns suitable for real-world traffic growth.

02 · Project

Minor Mentoring System Project

Graduation Project
Students
Spring MVC
Matcher
MySQL

Problem

University students need effective mentor matching based on skills, career goals, and mentor expertise, with a system to track mentorship progress and task completion.

Solution

Developed a full-stack mentorship platform with intelligent recommendation algorithm that analyzes multiple factors to create optimal mentor-student matches, along with comprehensive task management and progress tracking capabilities.

Tech stack

Backend

JavaSpring FrameworkSpring Security

Database

JPA/HibernateMySQL

Frontend

HTMLCSSBootstrap

Role

  • •Designed and implemented recommendation algorithm using skill-based matching and career goal analysis
  • •Built RESTful APIs for mentor-student matching, task management, and progress tracking
  • •Developed secure authentication and authorization system with Spring Security
  • •Designed database schema optimized for recommendation queries
  • •Integrated with university systems for student data synchronization

Architecture

Traditional MVC architecture with Spring Framework. Service layer implements recommendation algorithm, repository layer uses JPA for data persistence. RESTful API design with clear separation between matching logic and task management.

Impact

Successfully matches students with relevant mentors based on multiple criteria. Task management system enables structured mentorship programs with measurable outcomes.

Experience

Where I've shipped

Current08/2022 - Present

Backend Software Engineer (C)

ProGineer Technologies

Full-time

Key responsibilities

  • •Delivered backend services in C for performance-critical, memory-sensitive production systems across 5+ major projects with a team of 20 engineers
  • •Cut critical Oracle query runtime from ~2 hours to 1–4 seconds (99.9% faster) through restructuring, indexing, and execution-plan analysis
  • •Reduced another heavy query from 50 minutes to 3–5 seconds (99.8% faster) by rewriting joins, adding strategic indexes, and simplifying the query plan
  • •Accelerated a Cassandra API with parallelism, cutting runtime from 26s to 6s across 10,000 executions (77% faster)
  • •Modeled and managed databases with millions of records and 100+ tables across multiple schemas; designed 20 new tables for 2 major projects
  • •Drove 10–15+ production incident resolutions and performance fixes, including an on-prem optimization for an Asian customer that restored stability and earned strong client satisfaction
  • •Debugged production issues in constrained on-prem environments with no cloud access, using log analysis and system-level investigation to restore service
  • •Built and extended OpenSearch data-generation pipelines and structured document payloads (field normalization/denormalization) to keep source systems and search indexes aligned
  • •Partnered with cross-functional engineers on backend design and system-behavior decisions for scalability and correctness

Technologies

COracle SQLCassandra NoSQLOpenSearchInformix
Project

Software Engineer

Bloom – Venue Booking Platform

Personal Project

Designed and developed a production-ready venue booking platform from the ground up using Spring Boot 3.4 (Java 17). Architected secure server-side REST APIs with JWT authentication, MongoDB, AWS cloud infrastructure, and clean architecture, delivering core features including user management, venue management, bookings, offers, notifications, CI/CD, and cloud deployment. Built as a real-world product with a strong focus on scalability, maintainability, and production-quality engineering.

Key responsibilities

  • •Built a server-side Spring Boot REST API with layered clean architecture (Controllers → Services → Repositories → MongoDB) for Auth, User, Venue, and Offer domains
  • •Implemented JWT authentication with access/refresh tokens, BCrypt password hashing, RBAC (ADMIN/USER/OWNER/CUSTOMER), and a reusable Ownable/isOwner() check with @PreAuthorize
  • •Modeled MongoDB documents with soft deletes and a shared BaseEntity (IDs, audit timestamps, translation support); added custom queries and DTO mapping
  • •Delivered database-driven multi-language responses (EN/AR/HE) via Accept-Language resolution and nested translation maps—no schema migrations to add languages
  • •Added Jakarta Bean Validation with a custom @EnumTypeExists validator, global exception handling, and Swagger/OpenAPI docs
  • •Deployed the server-side API to AWS cloud (EC2, S3), set up CI/CD for build and release, and integrated Firebase plus an OpenAI chatbot for personalized suggestions

Technologies

Backend

Java 17Spring Boot 3.4Spring SecurityRESTful APIsServer-Side

Database

MongoDBSpring Data MongoDB

Cloud

AWS EC2AWS S3CI/CD

Security

JWTBCrypt

Integration

FirebaseOpenAISwagger/OpenAPI

Tooling

Maven
View on GitHub →

Learning

Always sharpening

Practice

Continuous learning for production backend work — not buzzwords.

Focus areas

  • ▸Advanced Database Optimization
  • ▸Microservices Architecture
  • ▸System Performance Tuning
  • ▸Search indexing pipelines

Technologies

  • ▸AWS Networking & Auto Scaling
  • ▸Secrets Management
  • ▸Container Orchestration
  • ▸Advanced SQL Techniques

Contact

Let's build something solid

Contact information

Prefer email or LinkedIn — happy to talk systems, architecture, and interesting problems.

Emailahmad.sa893@gmail.comPhone+970 597 267 624

Connect

LinkedInGitHub