Ohad Kravchick, Developer in Santa Clara, CA, United States
Ohad is available for hire
Hire Ohad

Ohad Kravchick

Verified Expert  in Engineering

Debugging Developer

Santa Clara, CA, United States

Toptal member since October 17, 2018

Expertise
DebuggingCode ReviewFull-stackJavaJavaScriptNode.jsReact.jsAPISystem SecurityOpenAILLMLinuxCSSUDP
Bio

Ohad has more than 15 years of experience building complex back-end, front-end, networking, and mobile systems. He focuses on building scalable, highly maintainable and testable systems, and debugging and maintaining high-availability of services. He takes pride in growing teams of capable engineers.

Portfolio

Google
Security
Coursera
WebDriver, Flow, React, Full-stack
Google, Apps, Gmail and Inbox
Bash, Python, ECMAScript (ES6), JavaScript, Java, Full-stack

Experience

  • Refactoring - 15 years
  • Code Review - 15 years
  • Debugging - 15 years
  • Application Security - 15 years
  • Java - 12 years
  • System Design - 12 years
  • Team Mentoring - 8 years
  • JavaScript - 8 years

Availability

Part-time

Preferred Environment

Git, IntelliJ IDEA, Vim Text Editor, Bash, Linux

The most amazing...

...under-the-hood infrastructure work I did was to upgrade Google Inbox/Gmail codebase from an arcane Java-to-JS compiler, mostly singlehandedly

Work Experience

Senior Software Engineer

2019 - PRESENT
Google
  • Managed and maintained internal identity and access management (IAM) systems.
  • Managed the lifecycle of user identities and access privileges within internal IAM systems.
  • Managed internal authentication systems, including multi-factor authentication (MFA), single sign-on (SSO), and password management solutions.
Technologies: Security

Web Infrastructure Software Engineer

2017 - 2018
Coursera
  • Led the growth team.
  • Built, scaled, and tested a few isomorphic high-throughput React.js web apps.
  • Improved developers' tool set for flow.js and webdriver.io.
  • Built a new, flexible multi-step onboarding workflow.
Technologies: WebDriver, Flow, React, Full-stack

Web Infrastructure Software Engineer

2016 - 2017
Google, Apps, Gmail and Inbox
  • Integrated a new Java→EcmaScript 6 transpiler.
  • Refactored Java code to adhere to Java subset suitable for transpiler.
  • Refactored JavaScript code to support ES6 and JsClosure’s modules.
  • Technically led a sub-team of four engineers during integration.
  • Developed low-level JavaScript benchmarking of output of new transpiler in preparation to support Inbox.
  • Coded many automatic source→source conversion tools in Python and bash.
Technologies: Bash, Python, ECMAScript (ES6), JavaScript, Java, Full-stack

Senior Software Engineer

2013 - 2015
Google, Ads, DoubleClick for Publishers
  • Supported a real-time, billion-dollar ad delivery system, mostly in Java.
  • Created Google’s next video advertisement platform.
  • Technically led a team of five front-end engineers.
  • Built a scalable back-end system to support millions of customers.
  • Wrote Java code and tests to extremely high standards.
  • Debugged and profiled production issues.
  • Designed many upcoming features and future integrations.
Technologies: MySQL, BigTable, GWT, Java, Full-stack

Mobile Software Architect

2011 - 2013
The New York Times
  • Designed and developed the NYTimes’ HTML5 single-page web app (app.nytimes.com) using HTML5, JavaScript ES5, and CSS3. Worked on this project from the very start and was a central part of the coding, launch, and ongoing support and maintenance.
  • Designed and developed the NYTimes’ next mobile website (in-progress) on Node.js using CoffeeScript, dust templates, LESS.
  • Designed and led the development of an A/B testing tool for www.nytimes.com.
  • Wrote automatically testable code using mocha, sinon.js, JSCoverage, and Silenium+JS Driver.
  • Wrote highly maintainable code broken into NPM modules, MVP, and UI components.
  • Served as an architect and led developers in my group technologically using brainstorming sessions, code reviews, peer programming, and demos.
  • Introduced and implemented back-end cutting-edge technologies: node.js, Redis, varnish, grunt.
  • Experienced with the latest front-end features – offline web applications, CSS3 transformations and transitions, local storage, WebSQL, and libraries – jQuery, Require.js, Backbone.js, Ext.JS / ST, and others.
  • Launched a new, innovative HTML5 product in a timely fashion with no technical problems.
Technologies: Grunt, Redis, Selenium, Sinon.JS, Mocha, CSS3, HTML5, CoffeeScript, JavaScript, Node.js, Full-stack

Lead Mobile Application Developer

2010 - 2011
Reuters
  • Developed and supported Reuters’ native iOS apps: “News Pro for iPhone” and “News Pro for iPad”; embedded external SDKs; debugged crashes; fixed bugs.
  • Designed, prototyped, led, and developed an entirely new content-driven HTML5 and JavaScript single-page web-app, using JavaScript, HTML templates, JQuery, CSS3, batched content delivery, offline caching, local storage caching, WebSQL, simple CMS, and multiple devices layouts.
  • Helped raise Reuters’ app rating from 3 to 4.5 by tackling and fixing long-time problems and crashes.
  • Maintained scalable back-end web services using Apache, Tomcat, JDBC, and memcache.
  • Acted as technical liaison between business developers, product managers, designers, editors, analysts, ad-ops, and third party providers, and the rest of the dev team (partly offshore).
Technologies: Memcached, JDBC, Apache Tomcat, Apache, JavaScript, CSS, HTML5, Objective-C

Professional Services Team Lead

2009 - 2010
Expand Networks
  • Generated revenue for Expand Networks by providing technical services to customers.
  • Developed Java applications and patches to reduce response time for customers.
  • Exclusively handled and executed all training of clients about Expand Networks’ products.
Technologies: Networking, Java

Network Instructor and Engineer

2000 - 2006
IDF
  • Trained about 30 new recruits in networking using lectures, tests, CBTs, and recorded videos.
  • Designed and implemented several new protocols in a large-scale network (100+ routers): routing protocols, multicast, and redundancy protocols.
  • Maintained a large-scale network of routers, switches, WAN, and Firewalls.
  • Proficiency with computer networks: TCP/IP, Ethernet and VLAN switching, IP, routing protocols, TCP and UDP, common applications, redundancy protocols, security, multicast, WAN.
Technologies: WAN, Multicast, Applications, UDP, Transmission Control Protocol (TCP), Routing, IPv4, VLANs, Ethernet, TCP/IP, Security, IP Networks, Networking

Co-Founder and Lead Web Developer

1998 - 2000
Bono Pie Israel
  • Founded, coded, and maintained a website with about 100,000 members.
  • Led a team of three web front-end and back-end developers.
  • Programmed a secured and scalable website in ASP (VBScript), SQL, JavaScript, Flash ActionScript, and Java applets.
  • Managed large-scale MS-SQL server set using SPs, indexes, and profiling.
  • Managed large deployment of IIS web servers.
Technologies: SQL, Applets, Java, Flash ActionScript, JavaScript, Microsoft SQL Server, Active Server Pages (ASP)

Programmer

1996 - 1998
Dolphin Ore LTD
  • Coded in VB, ASP, Access, and SQL.
Technologies: Microsoft Access, Microsoft SQL Server, Active Server Pages (ASP), VB

Experience

Reuters News Pro App

https://itunes.apple.com/us/app/reuters-news/id602660809?mt=8
Designed, prototyped, led, and developed an entirely new content-driven HTML5 and JavaScript single-page web-app, using JavaScript, HTML templates, jQuery, CSS3, batched content delivery, offline caching, local storage caching, WebSQL, simple CMS, and multiple devices layouts.

Content Management System for Kids

I have developed a prototype of a CMS for kids. The site allowed kids to edit and create content, sparking their creativity. The site had several integrations with AI to help improve their writing, embed generated images into their content, and review it before publishing.

Education

2009 - 2012

Master's Degree in Computer Science

Fordham University - Bronx, NY, USA

2003 - 2006

Bachelor's Degree in Computer Science

The Open University - Ra’anana, Israel

1999 - 2000

Associate's Degree in Electrical Engineering

Amit Amal Vocational School - Rishon Lezion, Israel

Skills

Libraries/APIs

React, Node.js, WebDriver, Sinon.JS, JDBC, jQuery, RxJava

Tools

Vim Text Editor, IntelliJ IDEA, Git, Flow, Mocha, Grunt, Apache, Apache Tomcat, Microsoft Access, JavaScript Testing, JavaScript Debugging

Languages

Java, JavaScript, Bash Script, Bash, ECMAScript (ES6), CoffeeScript, HTML5, CSS3, Objective-C, Active Server Pages (ASP), Flash ActionScript, VB, CSS, Python, SQL

Paradigms

Testing, Refactoring, Unit Testing

Platforms

JVM, Linux

Frameworks

GWT, Selenium, AngularJS, Bootstrap, React Native, Jersey, Vert.x

Storage

BigTable, Redis, Memcached, Microsoft SQL Server, MySQL

Other

Debugging, Code Review, Code Architecture, Front-end Development, Full-stack, UI Testing, API Testing, Network Security, API Design, IP Networks, Team Mentoring, Code Deployment, System Design, OpenAI, Large Language Models (LLMs), Networking, Security, TCP/IP, Ethernet, VLANs, IPv4, Routing, Transmission Control Protocol (TCP), UDP, Applications, Multicast, WAN, Applets, Application Security, HTTP, Open-source LLMs, Computer Science

Collaboration That Works

How to Work with Toptal

Toptal matches you directly with global industry experts from our network in hours—not weeks or months.

1

Share your needs

Discuss your requirements and refine your scope in a call with a Toptal domain expert.
2

Choose your talent

Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.
3

Start your risk-free talent trial

Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.

Top talent is in high demand.

Start hiring