Hire the Top 3% of Freelance Sinon.JS Developers

Toptal is a marketplace for top Sinon.JS developers, engineers, programmers, coders, architects, and consultants. Top companies and startups choose Toptal Sinon.JS freelancers for their mission-critical software projects.

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Hire Freelance Sinon.JS Developers and Engineers

Michael Kowalski

Freelance Sinon.JS Developer
AustraliaToptal Member Since May 3, 2021

Michael has an exceptional background in finance, business, and software. He is a certified SuperForecaster and MBA with knowledge of machine learning. At Credit Suisse, he produced $24 million in profit using bespoke software tools to identify statistical arbitrage transactions in the sovereign bonds of 20 countries and built a yield curve-based pricing model for Australian Bank Hybrid Bonds. Michael has industry experience in finance, energy, telecommunications, and publishing.

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Antoine Pham

Freelance Sinon.JS Developer
United StatesToptal Member Since October 18, 2018

Antoine is a seasoned professional with a unique blend of skill and passion for software development, making him an invaluable asset in any environment. His expertise spans all stages of the development cycle, from building engineering teams in startups to managing budgets, architecture, and processes at Fortune 500 companies. His unwavering passion for software development fosters inventive thinking and collaboration, inspiring teams to reach new heights.

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Said Kholov

Freelance Sinon.JS Developer
New ZealandToptal Member Since November 10, 2015

Said is an accomplished software developer with over a decade of experience in the field of computer science. He has honed his skills over the years and has become adept at leading front-end development teams on numerous successful projects. Said's diverse background has allowed him to work with software companies across a wide range of industries, enabling him to acquire a comprehensive understanding of various products and best practices.

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Artem Khamidullin

Freelance Sinon.JS Developer
RussiaToptal Member Since November 15, 2017

Artem has over ten years of experience in web development and architecture for various complex requirements, including projects that are not well-defined. He perfectly solves assigned tasks and even helps resolve the client's business problems. Artem is co-founder and CTO of FunFromMe startup.

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Veselin Dimitrov

Freelance Sinon.JS Developer
BulgariaToptal Member Since December 3, 2018

Veselin is a top-notch software engineer with the passion and experience to help businesses solve complex problems. Specializing in full-stack, highly scalable, real-time, cross-platform JavaScript and Node.js applications, he delivers world-class quality in terms of architecture, maintainability, and performance. He has worked in corporate as well as startup environments, and transparent communication is always prevalent in his work ethic.

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Andrii Naidenko

Freelance Sinon.JS Developer
PolandToptal Member Since August 26, 2019

Andrii is a Microsoft-certified full-stack developer with a master's degree in computer science. He has 15 years of industry experience delivering top-notch web, mobile, and hybrid software solutions through the application of Node.js and Angular technologies. Andrii completes successful projects by iterating outstanding software architecture, producing test-driven design concepts, and using Agile best practices.

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Iduart Dean Barrios

Freelance Sinon.JS Developer
ColombiaToptal Member Since December 10, 2021

Iduart is a full-stack developer and technical leader with nine years of experience, specializing in front-end development with JavaScript and React. He has also worked with a wide range of technologies, including PHP, .NET, jQuery, Angular, Durandal, Node.js, MongoDB, Elasticsearch, Oracle, and MySQL. Iduart has worked in education, healthcare, real estate, and eCommerce.

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Stefan Milovanovic

Freelance Sinon.JS Developer
SerbiaToptal Member Since December 16, 2020

Stefan is an experienced software engineer and full-stack web developer with a master's degree in computer science. He has worked for large corporations and startups and is accustomed to a distributed environment and working with remote clients using agile methodologies. JavaScript is his cup of tea, but he also has years of working with more than ten different programming languages under his belt.

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Iago Passos

Freelance Sinon.JS Developer
BrazilToptal Member Since March 14, 2022

Iago is currently working as a back-end developer for an educational startup in Brazil, developing the new architecture for their content management system. He is an expert in using Node.js and building the whole architecture on AWS cloud using lambda functions. Iago's prior experience involved using Node.js, Python, and Java, and designing microservices hosted on cloud platforms. In Iago, you will find a life-long learner eager to tackle challenging problems.

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Rob Sutcliffe

Freelance Sinon.JS Developer
United KingdomToptal Member Since February 16, 2022

Rob is a principal UI engineer with over a decade of professional experience working with React, Tailwind, and Next.js. He is particularly interested in data visualization using D3.js and Framer Motion animations. Rob has a design background as he has a degree in graphic communications and extensive experience working as a UI designer, design manager, and design consultant.

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Tayyab Hussain

Freelance Sinon.JS Developer
GermanyToptal Member Since January 31, 2022

Tayyab is a certified Salesforce Commerce Cloud (SFCC) developer with over six years of experience. He has worked on various projects remotely and as an in-house developer. Having experience in all aspects of software development and the full lifecycle for eCommerce products, Tayyab is on his way to becoming an architect in SFCC. Currently, he is working as a senior software engineer in Internet Stores.

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98% of Toptal clients choose to hire our talent after a risk-free trial.

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Toptal in the press

... allows corporations to quickly assemble teams that have the right skills for specific projects.

Despite accelerating demand for coders, Toptal prides itself on almost Ivy League-level vetting.

Our clients
Creating an app for the game
Conor Kenney
Creating an app for the game
Leading a digital transformation
Elmar Platzer
Leading a digital transformation
Building a cross-platform app to be used worldwide
Building a cross-platform app to be used worldwide
Drilling into real-time data creates an industry game changer
Drilling into real-time data creates an industry game changer
What our clients think
Clients Rate Toptal Sinon.JS Developers4.4 / 5.0on average across 8,716 reviews as of May 18, 2024
Tripcents wouldn't exist without Toptal. Toptal Projects enabled us to rapidly develop our foundation with a product manager, lead developer, and senior designer. In just over 60 days we went from concept to Alpha. The speed, knowledge, expertise, and flexibility is second to none. The Toptal team were as part of tripcents as any in-house team member of tripcents. They contributed and took ownership of the development just like everyone else. We will continue to use Toptal. As a startup, they are our secret weapon.

Brantley Pace

CEO & Co-Founder

I am more than pleased with our experience with Toptal. The professional I got to work with was on the phone with me within a couple of hours. I knew after discussing my project with him that he was the candidate I wanted. I hired him immediately and he wasted no time in getting to my project, even going the extra mile by adding some great design elements that enhanced our overall look.

Paul Fenley


The developers I was paired with were incredible -- smart, driven, and responsive. It used to be hard to find quality engineers and consultants. Now it isn't.

Ryan Rockefeller


Toptal understood our project needs immediately. We were matched with an exceptional freelancer from Argentina who, from Day 1, immersed himself in our industry, blended seamlessly with our team, understood our vision, and produced top-notch results. Toptal makes connecting with superior developers and programmers very easy.

Jason Kulik


As a small company with limited resources we can't afford to make expensive mistakes. Toptal provided us with an experienced programmer who was able to hit the ground running and begin contributing immediately. It has been a great experience and one we'd repeat again in a heartbeat.

Stuart Pocknee


How to Hire Sinon.JS Developers Through Toptal


Talk to One of Our Industry Experts

A Toptal director of engineering will work with you to understand your goals, technical needs, and team dynamics.

Work With Hand-Selected Talent

Within days, we'll introduce you to the right Sinon.JS developer for your project. Average time to match is under 24 hours.

The Right Fit, Guaranteed

Work with your new Sinon.JS developer for a trial period (pay only if satisfied), ensuring they're the right fit before starting the engagement.

Find Experts With Related Skills

Access a vast pool of skilled developers in our talent network and hire the top 3% within just 48 hours.


  • How are Toptal Sinon.JS developers different?

    At Toptal, we thoroughly screen our Sinon.JS developers to ensure we only match you with talent of the highest caliber. Of the more than 200,000 people who apply to join the Toptal network each year, fewer than 3% make the cut. You’ll work with engineering experts (never generalized recruiters or HR reps) to understand your goals, technical needs, and team dynamics. The end result: expert vetted talent from our network, custom matched to fit your business needs.

  • Can I hire Sinon.JS developers in less than 48 hours through Toptal?

    Depending on availability and how fast you can progress, you could start working with a Sinon.JS developer within 48 hours of signing up.

  • What is the no-risk trial period for Toptal Sinon.JS developers?

    We make sure that each engagement between you and your Sinon.JS developer begins with a trial period of up to two weeks. This means that you have time to confirm the engagement will be successful. If you’re completely satisfied with the results, we’ll bill you for the time and continue the engagement for as long as you’d like. If you’re not completely satisfied, you won’t be billed. From there, we can either part ways, or we can provide you with another expert who may be a better fit and with whom we will begin a second, no-risk trial.

Tap Into World-Class Talent

  • Trusted Experts Only

    Trusted Experts Only

    All of our talent are seasoned experts who ramp up quickly, readily contribute as core team members, and work with you to minimize onboarding time.

  • The Right Fit

    The Right Fit

    We have a knack for matching you with the right fit. Start working with your new hire on a no-risk trial period, paying only if satisfied.

  • Scale as Needed

    Scale as Needed

    Hire talent within 48 hours and scale your team up or down as needed, no strings attached.

  • Seamless Hiring

    Seamless Hiring

    We handle all aspects of billing, payments, and NDA’s. Let us take care of the overhead while you focus on building great products.

  • Flexible Engagements

    Flexible Engagements

    Choose the engagement type that suits your needs — hourly, part-time, or full-time — with the ability to change anytime.

  • Expert Talent Matching

    Expert Talent Matching

    Focus on your project and enjoy support from your dedicated account executive and expert talent matcher.

Featured Toptal Sinon.JS Publications

Top Sinon.JS Developers Are in High Demand.

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