VWO is a leading Digital Experience Optimization platform trusted by over 3,000 businesses in 100+ countries, including global brands like Samsung, Vodafone, Toyota, HBO, and Domino's. What began 15 years ago as one of the world’s first A/B testing tools has since evolved into a comprehensive, enterprise-grade platform used by product, marketing, and growth teams to experiment, personalize, analyze behavior, and build exceptional digital experiences.

Today, VWO offers a full-stack suite for A/B testing, multivariate testing, feature rollouts, heatmaps, session recordings, behavioural analytics, surveys, personalization, and more across web, mobile, and server-side applications — all in one unified platform. We enable teams to make confident, data-driven decisions that drive user engagement, retention, and conversion

.
VWO is a profitable, founder-led business with $50M+ ARR, strong EBITDA margins, and a history of capital-efficient, sustainable growth. In January 2025, Everstone Capital acquired a majority stake in the company to help accelerate our global expansion — both organically and inorganicall

y.
We are a fully remote team of 450+ people, with go-to-market teams across the Americas, Europe, and APAC, and product and engineering anchored in India. Our culture values deep thinking, fast execution, and strong ownership — with minimal bureaucracy and high autonomy. Despite our scale, we continue to operate with the agility and ambition of a start

up.
As a Senior JavaScript Engineer, you will play a pivotal role in developing and maintaining high-performance JavaScript libraries that power all the core features of VWO. These libraries are deployed on our customers’ websites, directly impacting millions of users worldwide and enabling seamless digital experien

ces.
At Wingify, we have a deep passion for vanilla JavaScript and work with advanced technologies like TypeScript, Rollup.js, Cypress, and ESLint to build robust, scalable solut

ions.We are unwavering in our commitment to Web Performance, constantly striving to optimize and inno

vate.Discover some of our efforts here: https://engineering.wingify.com/posts/performance-improvements-in-vwo-smart

-code
Job Responsibi

litiesDevelop and maintain core JavaScript libraries that serve as the backbone of our pro
jects.Write clean, modular, and reusable code that can be leveraged across multiple JavaScript libraries and pro
jects.Engage with the developer community by sharing your expertise and experiences through blog posts, open-source contributions, and discussions. Explore our Engineering Blog and GitHub page to see how we give back to the comm

unity.
Skills & Exp

erienceRequired Qualifi

cationsExperience: 3–6 years in software development with a strong focus on Java
Script.Proficiency: Expertise in Vanilla JavaScript, HTML, a
nd CSS.TypeScript: Hands-on experience with TypeScript in production enviro
nments.Browser Knowledge: Deep understanding of browser internals, including the DOM, browser events, JavaScript APIs, and canvas ren
dering.Optimizations: A strong focus on delivering optimized content for fast user exper

iences.
Technical E

xpertiseKnowledge of high-level programming concepts like Promises and data-
binding.Experience writing modular, maintainable JavaScri
pt code.Exceptional debugging skills to identify and resolve issues effi
ciently.Strong understanding of cross-browser compatibility and differences across modern and legacy b

rowsers.
Testing & A

utomationA passion for writing automated tests to ensure reliability and stability across devices and
browsers.Experience with testing frameworks such as Cypress or simil

ar tools.
S

oft SkillsA mindset of continuous learning to stay updated with the ever-evolving front-end
ecosystem.A collaborative attitude and willingness to share knowledge and improve team

practices.
Wh