Onur is available for hire

Onur Ari

Verified Expert in Engineering

Software Developer

Ankara, Turkey

Toptal member since October 26, 2021

Expertise

Full-stack Code Review Front-end REST API JavaScript TypeScript CSS Python React.js Django Redux GraphQL SaaS

Bio

Onur is a senior software engineer and engineering squad lead with 5+ years of experience and a passion for creating complex, resilient, and scalable web applications. He specializes in React and TypeScript, Python, and Django, and his experience ranges from startups to established corporations. Onur has a strong work ethic, communicates well, and quickly learns and applies new technologies.

Portfolio

Jasper Health

Django, Next.js, React, JavaScript, PostgreSQL, GraphQL...

Picus

TypeScript, React, Redux, Tailwind CSS, React Query, React Apollo, REST APIs...

Obss

JavaScript, Redux, MobX, CSS, HTML, React, GitHub, Tree Structures, REST APIs...

Experience

TypeScript - 5 years
JavaScript - 5 years
CSS - 4 years
Python - 4 years
Django - 3 years
React - 3 years
GraphQL - 2 years
Node.js - 2 years

Availability

Part-time

Preferred Environment

Git, GitHub, Linux, MacOS

The most amazing...

...thing I've developed is a data monitoring web application used in several hospitals with thousands of daily patients.

Work Experience

Senior Software Engineer | Engineering Squad Lead

2021 - 2024

Jasper Health

Acted as one of the 1st engineers at Jasper Health, where I led the consumer product software team for over a year, contributing to the company’s $25 million Series A funding.
Delivered high-quality work using Django, GraphQL, and Next.js, securing contracts with over five major health tech companies, including EDHC, MSK, and Accredo.
Implemented core features like chat (video and messaging), library (articles), notes and documents, and onboarding, significantly boosting user acquisition.
Migrated 100% of the health data to FHIR and built a process that automatically synchronizes FHIR and PostgreSQL whenever data is updated through Django ORM.
Proposed using serverless architecture and helped the team move various services, such as webhooks and analytics, to Google Cloud Functions. It increased performance and made the code more manageable.
Refactored code and optimized resource-intensive processes, including long job queues and SQL queries, while maintaining code coverage above 85%.
Integrated 3rd-party tools such as Sentry, Braze, Stripe, Getstream, and Agora.

Technologies: Django, Next.js, React, JavaScript, PostgreSQL, GraphQL, Fast Healthcare Interoperability Resources (FHIR), HIPAA Compliance, Material UI, Google Cloud Platform (GCP), CI/CD Pipelines, Unit Testing, Pytest, Docker, Google Cloud Functions, Terraform, Google Pub/Sub, Full-stack, Software Architecture, Apollo, REST APIs, Heroku, Full-stack Development, Architecture, Code Review, Redis, Serverless Architecture, GitHub Actions, Front-end, SaaS, Single Sign-on (SSO)

Front-end Developer

2021 - 2021

Picus

Created responsive, scalable, and performant user interfaces while collaborating with the design team in a fast-paced environment.
Made pivotal contributions to the company's core product, which helped the owners raise $24 million in Series B funding.
Delivered an in-house project’s front end from scratch before the deadline.
Delivered new features to Picus.io by managing the development and release processes.

Technologies: TypeScript, React, Redux, Tailwind CSS, React Query, React Apollo, REST APIs, Axios, Architecture, Code Review, GitHub Actions, Front-end, SaaS

Front-end Developer

2020 - 2021

Obss

Significantly increased performance in multiple components and pages by optimizing React re-renders.
Created an advanced React tutorial to help my teammates increase their knowledge of common React concepts. The tutorial is available in my GitHub profile.
Built an interactive tree visualization component with React and pure HTML and CSS.
Provided consulting services to ASELSAN, one of the biggest defense corporations in Turkey.

Technologies: JavaScript, Redux, MobX, CSS, HTML, React, GitHub, Tree Structures, REST APIs, Axios, Code Review, Front-end, SaaS

Software Engineer

2018 - 2020

SRDC

Contributed significant value to Mantiq, a business intelligence product used by hospitals for business management and data monitoring.
Added core features to Mantiq, such as dark mode, mobile compatibility, and drag and drop.
Refactored the legacy code, leading to a remarkable increase in code reusability and maintainability.
Built a dynamic map component that provides a user interface for geographical data filtration.

Technologies: TypeScript, JavaScript, Angular, Node.js, Scala, MongoDB, PostgreSQL, CSS, HTML, Full-stack, ETL, REST APIs, Full-stack Development, Code Review, Redis, Front-end, SaaS

Full-stack Software Developer

2018 - 2018

Spacemining

Joined the company in the early startup stage and played a crucial role in developing the MVP while collaborating with mining engineers to determine the requirements.
Created and maintained the whole project as the sole developer.
Implemented complex mathematical formulas used in the mining industry.

Technologies: Java, Spring Boot, Angular, MongoDB, Bootstrap, CSS, HTML, Full-stack, REST APIs, Full-stack Development, Front-end

Experience

Halcyon

https://github.com/onurarrii/halcyon-backend

A mobile app for users to track their yoga challenges, practices, lessons, articles, etc. I developed the back end using Django and GraphQL.

The demo video can be found here: https://drive.google.com/file/d/143i8KuVKU7U4ojdqif-9gnm1IUtcJYGV/view?usp=sharing

React Tutorials

https://github.com/onurarrii/ReactJS-Tutorials

A tutorial project that includes advanced and intermediate React concepts with code and UI examples. The main focus is on creating performant UI components by optimizing re-renders, and they also cover some React pitfalls and misconceptions. I created the tutorials to help my teammates increase their knowledge and learn new skills.

My Reminder

https://github.com/onurarrii/My-Reminder

A simple application written in React Native that enables users to create a bucket list and set reminders. I created this project to become more familiar with React Native and its animation libraries.

CTF Challenges

https://github.com/onurarrii/ctf-challenges

A college project that featured four capture-the-flag (CTF) challenges. Each challenge focused on a different cybersecurity concept: CAPTCHA, dictionary attacks, encryption, and SQL injection. All the challenges included a description and a solution.

Collaborative XML Document

https://github.com/onurarrii/collaborative-xml-docbook

A web application used for collaborative XML document editing. It works in a manner that's similar to Google Docs. Multiple users can make changes on the same document simultaneously, and each change is reflected immediately to other users, which is accomplished using WebSockets.

Education

2015 - 2020

Bachelor's Degree in Computer Engineering

Middle East Technical University - Ankara, Turkey

Skills

Libraries/APIs

React, REST APIs, Node.js, React Query, MobX

Tools

Pytest, Git, GitHub, Elastic, Terraform, React Apollo

Languages

JavaScript, TypeScript, CSS, Python, GraphQL, Scala, Java, HTML

Frameworks

Redux, Django, Angular, Next.js, Material UI, Tailwind CSS, Spring Boot, Bootstrap, React Native

Paradigms

Functional Programming, Unit Testing, Agile Software Development, Object-oriented Programming (OOP), Concurrent Programming, Serverless Architecture, Fast Healthcare Interoperability Resources (FHIR), HIPAA Compliance, ETL

Platforms

Docker, Linux, MacOS, Google Cloud Platform (GCP), Heroku

Storage

MongoDB, PostgreSQL, Redis, SQL Injection Protection

Industry Expertise

Cybersecurity

Other

Data Structures, Google Cloud Functions, Google Pub/Sub, Full-stack, Full-stack Development, Axios, Code Review, Front-end, Operating Systems, Algorithms, CI/CD Pipelines, Software Architecture, Architecture, GitHub Actions, SaaS, Web Security, WebSockets, Tree Structures, Capture the Flag (CTF), CAPTCHA, Encryption, Apollo, Single Sign-on (SSO)

Collaboration That Works

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