Rizwan Rizvi, Developer in Seattle, WA, United States
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Rizwan Rizvi

Verified Expert  in Engineering

Complex Problem Solving Developer

Seattle, WA, United States
Toptal Member Since
June 13, 2018

Rizwan has a reputation for overcoming complex challenges through clear thinking, innovative approaches, and enhancing communication between different parts of organizations. Throughout his career, he has optimized the efforts of diverse and dispersed teams of IT professionals and has consistently delivered projects profitably in challenging environments.


Reward Gateway, Limited
Security, Mobile Security, iOS, Swift, OWASP, React Native, Android, Kotlin
Toptal Client
Security, Mobile Security, iOS, Swift, OWASP, React Native, Android, Kotlin
Blockchain, Ethereum Smart Contracts, Solidity, Ethereum, Smart Contracts...




Preferred Environment

.NET, GitHub, Visual Studio, Windows

The most amazing...

...project I've worked on was a mental disorder diagnosis expert system which now runs publicly and has helped thousands of patients with treatment.

Work Experience

iOS Security Engineer

2023 - 2023
Reward Gateway, Limited
  • Fixed TLS/SSL-related issues and performed certificate pinning to secure API calls.
  • Protected the app from being run on Jailbroken devices. Added protection from debugger attachment.
  • Added stack overflow protection by adding compiler-level stack protection checks.
Technologies: Security, Mobile Security, iOS, Swift, OWASP, React Native, Android, Kotlin

iOS Security Engineer

2022 - 2023
Toptal Client
  • Created tech strategy for solving the iOS app's binary protection.
  • Implemented a keychain validation to fortify biometric authentication.
  • Fixed security issues in Swift identified during Pentesting.
Technologies: Security, Mobile Security, iOS, Swift, OWASP, React Native, Android, Kotlin

Principal Engineer, Web2 and Web3

2021 - 2022
  • Architected end-to-end solutions and coding core components for an application that runs on both Web2 and Web3.
  • Helped with goal setting, providing clarity, and solving ambiguous problems.
  • Assisted with prioritization and dependency management.
Technologies: Blockchain, Ethereum Smart Contracts, Solidity, Ethereum, Smart Contracts, Full-stack, Front-end, Spring Boot, Go, Back-end, Amazon Web Services (AWS), Amazon Aurora, The Graph, Magic Link Authentication, Moralis, Sentry, MetaMask, Etherscan, Cloud, Alchemy, IPFS, Security

Cybersecurity Tech Lead

2021 - 2021
[Toptal Client]
  • Identified ISO 27001 scope of audit for small businesses.
  • Performed in-depth gaps analysis to identify the security posture of the organization.
  • Identified risks and provided recommendations for how to mitigate them.
Technologies: ISO 27001, IT Security, Cybersecurity, Compliance, Security, Mobile Security

C#/C++/Node.js Developer

2020 - 2020
Dentium RC LLC
  • Created a C# desktop application that connects for oral examination webcams.
  • Integrated desktop application with the website to open on click using custom windows protocols.
  • Created setup and deployment project to correct install required dependencies and register custom protocols.
Technologies: C#, Windows Forms (WinForms), C++, USB, Webcams, Webcam SDK, Asynchronous Pluggable Protocol, Custom Protocols

Senior Full-stack Developer

2020 - 2020
  • Developed integration with Zapier, Gmail, Google Docs, Google Drive, and Slack.
  • Created test cases using the Behave BDD framework to ensure that tests meet user acceptance criteria.
  • Debugged and improved blockchain integration using W3, Nest, and Scrypt algorithms.
Technologies: Ethereum, Behave, LinkedIn API, Gmail API, Slack App, Google Drive API, Blockchain, SQLAlchemy, Flask, NSQ.io, MySQL, Python, Google Cloud, Zapier

Back-end Java Developer

2019 - 2020
Enterprise, Fintech, and Banking Client (via Toptal)
  • Created a search system for finding branches and ATMs filtered by various criteria, including a nearby feature.
  • Wrote unit tests and integration tests using JUnit and Cucumber.
  • Implemented performance optimizations by introducing lat/long caching on top of a Geo Time Zone API.
  • Ensured that all of the REST APIs adhered to JSON API standards.
  • Implemented the front end using React and developed components from scratch.
Technologies: React, JUnit, Node.js, Docker, Spring, Apache Lucene, Java

API Developer

2019 - 2019
Client (via Toptal)
  • Built new REST APIs in the existing codebase to provide new endpoints for the Zapier integration.
  • Developed a Zapier-based app using Zapier CLI and Node.js which provided actions and triggers to app users.
  • Implemented the Zapier UI in the app so that the user could enjoy dynamically populated custom fields.
Technologies: Node.js, Vagrant, REST, Zapier, PostgreSQL, Django, Python

C and Python Engineer

2019 - 2019
Client (via Toptal)
  • Ported existing LPSolve-based code written in C to PuLP using Python.
  • Helped solve hard mathematical equations optimizing consignment delivery routes, number of trucks, capacity, weight, and costs.
  • Added new attributes to the ported code to optimize the solutions even further.
Technologies: Mathematics, Dynamic Programming, Linear Programming, C, Python

Full-stack Developer

2019 - 2019
Client (via Toptal)
  • Performed AWS single sign-on investigation and integration.
  • Wrote Angular code using Amplify SDK to integrate with AWS.
  • Developed test cases using Jasmine and Karma.
Technologies: AWS Amplify, Amazon Cognito, Angular, Amazon EC2, Apache Kafka, NGINX, Apache Storm, MySQL, Elasticsearch, Node.js, Laravel, Django, Python

Full-stack Python Architect

2018 - 2018
Client (via Toptal)
  • Thoroughly analyzed the current state of the project and codebase.
  • Handled requirements gathering and scope definition for future enhancements.
  • Proposed architectural changes when necessary.
Technologies: System Architecture, Scope Management, Learning, Training, Training & Training Content Development, Requirements Analysis, Django, JavaScript, CSS3, HTML5, Python

Back-end Software Engineer (Google App Engine and Python)

2018 - 2018
Client (via Toptal)
  • Defined, designed, and developed high-performance back-end services for our web applications.
  • Performed test-driven development (TDD).
Technologies: Amazon Web Services (AWS), Git, SaaS, Java, Database Caching, Google App Engine, Unit Testing, REST APIs, RESTful Development, Software Design, Python

Senior Architect

2017 - 2018
  • Influenced and coached regional development crews that utilized a breadth of technologies including AWS, C#, Python, TypeScript, Lambda, PostgreSQL, SQL Server, and various other tech stacks for performance-oriented and clean solutions.
  • Created the technical architectural vision for a desktop application migration; used the TOGAF framework.
  • Developed charters and contributed towards an architectural governance board as a member overseeing the architectural alignments, ISO 27001 compliance, and best practices for implementation and delivery.
  • Coached and trained teams through mobbing sessions and formal training sessions for IT Security, SOLID principles, performance management, and CI/CD.
  • Developed PoCs which contributed towards performance gains for applications bringing down response time from 800 milliseconds to 15 milliseconds per request.
  • Guided and developed the architecture for new projects all the while addressing concerns around data migration, tech choices, performance, and security.
Technologies: Amazon Web Services (AWS), SaaS, MySQL, Microsoft SQL Server, NoSQL, Amazon DynamoDB, AWS Elastic Beanstalk, AWS Lambda, Windows, Linux, Docker, Kubernetes, .NET Core, Python, C#, .NET, OWASP

Chief Architect

2015 - 2017
Aurea Software
  • Developed website and application interfaces using a variety of technologies, including .NET, Java, SharePoint, Python, and PHP.
  • Architected and developed enterprise-grade solutions for a large client base using Amazon Web Services (AWS) infrastructure, including Elasticsearch, EC2, ECS, Elastibeanstalk, Docker and Kubernetes; managed up to five architects.
  • Solved issues related to the integration of legacy applications and SMS aggregators, web applications with existing SharePoint applications, AWS directory services with SaaS platforms and LDAP and MS AD with cloud platforms for single sign-on.
  • Architected an AWS-dependent cloud solution for the NextDoc document management system which provided an exit from the SharePoint platform—leading to a 90% decrease in the licensing and hosting costs. It also enabled new features to be added which were previously technically impossible.
  • Overcame issues associated with a lack of requirements, various deployments spread across multiple branches of code, no access to professional services, new requirements, the departure of employees from a recent acquisition, and budget cuts.
  • Introduced the concept of behavior-driven development.
  • Established requirements gathering, an approval framework, and a SaaS foundation framework for architects.
Technologies: Amazon Web Services (AWS), Elasticsearch, Python, ASP.NET, Classic ASP, PHP, SharePoint, SaaS, Visual Basic, Java, .NET, OWASP

Solutions Architect

2015 - 2015
The Gruden Group
  • Coordinated up to 12 offshore resources.
  • Architected and developed web and mobile solutions across diverse technologies including AWS, .NET, ColdFusion, and Sitecore.
  • Developed back-end APIs for iOS and Android apps.
  • Assisted with iRAP and ISO 27001 security compliance.
  • Performed code and architectural reviews.
Technologies: Amazon Web Services (AWS), Sitecore, Adobe ColdFusion, .NET, Security, OWASP

Director | Founder | Solutions Architect | Lead Developer

2008 - 2015
  • Architected and developed solutions while managing up to 22 resources.
  • Worked with various mobile technologies including .NET based solutions for websites and desktop-based applications.
  • Reduced the company’s annual employee turnover from 80% to 10% and dramatically improved team morale and productivity.
  • Saved more than $3 million for Swinburne University by redesigning the architecture and writing code converters in collaboration with the university on a one-year project to develop an online psychological support platform for Mentalhealth.org.au.
  • Reduced customer complaints by introducing frameworks to manage customer expectations, mandating the use of software quality measures, and enabling account managers and technical delivery staff to understand each other’s roles.
  • Worked with international money managers, brokers and startups to develop automated trading platforms for their customers. The algorithm that I developed won Dukascopy’s strategy development competition.
Technologies: Web Forms, ASP.NET, MySQL, Microsoft SQL Server, Perl, Visual Basic, C#, TFS, .NET, Security, Mobile Security, React Native, OWASP, Kotlin

HP Business Partner Solutions Architect | Security Consultant | Performance Consultant

2010 - 2014
Triforce Australia
  • Designed and architected enterprise infrastructure solutions based on HP technology around servers, storage, and networking for ANZ, Westpac, Swinburne University, Verbit, and OZForex. The designs always passed HP verification, the customers were consistently satisfied with the performance, and the work I undertook provided numerous upsell opportunities.
  • Worked in partnership with HP and implemented the first data center shipping container in Australia for Verbit.
  • Provided vulnerability scanning and compliance services to clients including ANZ to protect them from potential security breaches and millions of dollars in losses.
  • Advised customers and undertook performance tuning for SQL Server, SAP, and Oracle.
  • Conducted WiFi surveys to resolve contention and signal strength issues over large fields.
Technologies: Database Administration (DBA), Windows, Microsoft SQL Server, .NET, PCI, ISO 27001, HP Servers, HP EVA SAN

IT Security Auditor | Anti-money Laundering Analyst and Developer

2009 - 2010
Risk Associates
  • Worked with globally renowned hackers and security professionals to conduct security and compliance audits for financial institutions and gaming companies.
  • Analyzed data reported to compliance agencies and identified and reported suspicious transactions.
  • Accelerated the auditing process by developing the first software in the world that automatically downloaded data from various agencies and compliance organizations, analyzed it, and generated reports within hours with no manual intervention.
Technologies: Due Diligence, Visual Studio Tools for Office (VSTO), Microsoft 365, Microsoft SQL Server, .NET, Security, Mobile Security, OWASP

Mental Health Online

An expert system developed on ASP.NET that intelligently diagnoses mental disorders, gives appropriate program recommendations and gives the capability of monitoring.

EPM Live

A SharePoint-based enterprise project management tool; I refactored the whole codebase to solve the cyclic referencing issues between projects.


A mobile-messaging platform that handled over a billion transactions a day. I improved the workflow engine and added a workflow designer which allowed professional services to create, test, customize, and clone workflows easily. The project utilized various technologies including Angular, C#, PHP, and Classic ASP.


I rearchitected the whole SharePoint-based solution to a high-performing low-cost SaaS application using AngularJS, C# and various AWS technologies.

App For Trainers

I designed and developed a suite of mobile apps called App for Trainers; it was built using various technologies including Cordova, Appcelerator, and native Android and iOS code.


I added various features and improved DevFactory's CI/CD monitoring and reporting functionality; it was built on Java.


The Australian government's official tendering system. It was originally built on ColdFusion, and I architected and executed the migration from ColdFusion to .NET, Angular JS and AWS architecture.


I developed the back-end of a Web API for a MyFiziq, a mobile app that talks to an AI-based avatar generation system and keeps track of your weight and makes scientific predictions about your physique.

Forms Engine API

This is a Forms Engine component developed using Python, Flask, and AWS Lambda, utilizing AWS Elasticache and Elasticsearch. It was deployed on Docker containers in AWS ECS.

The Forms Engine provided back-end API support for tax forms to be created and rendered dynamically over the web using RESTful APIs.

Trial Balance API

The Trial Balance API provided trial balance calculations and rendering of data; it was built on Python and deployed on AWS Lambda and Docker containers.

PowerApp with Sharepoint Online and Rest API

Created a data visualization mobile application for a tier 1 product barcode provider. The app collated information from a sharepoint online library and a rest api using powerapps.


HTML, HTML5, C#, C#.NET, Visual Basic 6 (VB6), Visual Basic .NET (VB.NET), Visual Basic for Applications (VBA), Python, C, Java, PHP, Visual FoxPro, Swift, Kotlin, Visual Basic, Perl, CSS3, C++, ANSI C, SQL, JavaScript, XML, XSLT, CSS, Visual J++, Assembly Language, Solidity, Go


.NET Core, Angular, Angular Material, .NET Compact, ASP.NET MVC, React Native, TOGAF, .NET, ASP.NET, Spring, JUnit, Flask, Classic ASP, Django, Laravel, PHPUnit, iOS SDK, Android SDK, Spring Boot, Alchemy


LINQ, GitHub API, jQuery, REST APIs, Node.js, Auth0 API, Ajax Control Toolkit, React, YouTube API, Vimeo API, AWS Amplify, Apache Lucene, NSQ.io, SQLAlchemy, Google Drive API, Gmail API, LinkedIn API, Windows Forms (WinForms), AES


Behave, ACL, Visual Studio .NET, C#.NET WinForms, Amazon Simple Email Service (SES), AWS SDK, Amazon Simple Queue Service (SQS), Amazon Elastic Container Service (Amazon ECS), Angular CLI, TFS, GitHub, Microsoft Team Foundation Server, MSTest, Adobe AIR, Microsoft Power Apps, Bitbucket, TeamCity, xUnit, Adobe ColdFusion, Zapier, Visual Studio, Visual Studio Tools for Office (VSTO), Git, Apache Storm, NGINX, Amazon Cognito, Vagrant, Webcam SDK, Amazon ElastiCache, Aha!, WCF RIA Services, Jenkins, Microsoft Visual C++, Sentry, MetaMask, Etherscan


ACID, Agile, Unit Testing, Requirements Analysis, Linear Programming, Dynamic Programming, REST, RESTful Development, Refactoring, Photoshop Design


Android, Amazon EC2, AWS Lambda, Docker, Windows, Oracle, iOS, Kubernetes, Firebase, Google Cloud Platform (GCP), YouTube, Linux, AWS Elastic Beanstalk, SharePoint, Google App Engine, Apache Kafka, Amazon Web Services (AWS), Blockchain, Ethereum, Red Hat Linux


Amazon DynamoDB, SQL Server 2014, SQL Server 2008 R2, Amazon S3 (AWS S3), Elasticsearch, MySQL, NoSQL, Google Cloud, Microsoft SQL Server, Web Forms, HP EVA SAN, HP Servers, Database Administration (DBA), Database Caching, PostgreSQL, Amazon Aurora

Industry Expertise

Cybersecurity, Project Management


Slack App, Enterprise Software, PCI DSS, Technical Architecture, Solution Architecture, Cloud Computing, IIS, Complex Problem Solving, SDKs, Enterprise Architecture, SOLID Principles, ISO 27001, Ajax, APIs, High Availability Disaster Recovery (HADR), Security Testing, Security Audits, PCI Compliance, Security, System Security Developer, Mobile Security, OWASP, Clustering, Artificial Intelligence (AI), SaaS, Sitecore, PCI, Microsoft 365, Due Diligence, Software Design, Training, Learning, Scope Management, System Architecture, Mathematics, USB, Webcams, Asynchronous Pluggable Protocol, Custom Protocols, IT Security, Compliance, Training & Training Content Development, AI Design, Ubuntu Server, Code Review, Ethereum Smart Contracts, Smart Contracts, Full-stack, Front-end, Back-end, The Graph, Magic Link Authentication, Moralis, Cloud, IPFS, Information Systems

2002 - 2004

Master of Science Degree in Artificial Intelligence

Khadim Ali Shah Bukhari Institute of Technology - Karachi, Pakistan

1998 - 2002

Bachelor of Science Degree (Honors) in Computing and Information Systems

London Metropolitan University - London, UK


Hadoop Developer



HP Solutions Architect

Hewlett Packard Enterprise





Assembly Language


Collaboration That Works

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