Ruby Labs is a leading tech company that creates and operates innovative consumer products. We offer a diverse range of opportunities across the health, education, and entertainment industries. Our innovative teams are driving the future of consumer-led products, and we're always looking for passionate individuals to join us. Learn more about our story at: https://rubylabs.com/about-us/
About the roleWe are looking for a hands-on Senior CRO Manager to drive conversion growth for one of our core D2C subscription products. You will be fully responsible for a continuous pipeline of A/B tests - from hypothesis and prioritisation through launch, analysis, and documented verdicts - working with the CRO Lead to grow the number of statistically validated winners across the funnel.
This is a high-impact role suited for someone who treats experimentation as a system, not a list of ideas. Tests without a clear hypothesis, verdicts called before the evidence supports them, and results that are not documented are not acceptable. You are expected to know the funnel numbers, segment before you conclude, and work closely with the data team, product, and engineering. The bar is high and so is the upside - performance here is directly and significantly rewarded, and strong operators take on bigger scope fast.
Key ResponsibilitiesExperiment Pipeline: Own the A/B test backlog from hypothesis to launch. Prioritise ideas by expected impact, confidence, and effort, and keep the pipeline full so live traffic is always being used to learn.
Funnel Analysis: Analyse the funnel in Mixpanel to find drop-offs, friction points, and segment-specific opportunities across devices and locales, and turn them into testable hypotheses.
Test Analysis & Verdicts: Read results with statistical rigour, separate winners from directional trends and noise, and prepare clear verdicts for sign-off with the data team.
Test Specification & QA: Write test specs and variant briefs that developers can build without follow-up questions, and check every variant before and after launch.
Conversion Copy & Layouts: Produce conversion-oriented copy and layout variants that stay within compliance constraints on product claims.
Documentation & Reporting: Keep every test documented in Notion with hypothesis, setup, result, and learning, and contribute to regular experimentation reporting for leadership.
Mentoring: Support a junior CRO specialist on test design, analysis, and documentation standards.
Must-Have Experience
CRO / Experimentation: 3+ years running A/B tests on a D2C subscription or consumer web product, with results you can attribute to your own work.
Product Analytics: Hands-on proficiency in Mixpanel or a close equivalent - building funnels, segmenting by device and geography, and reading cohort behaviour without analyst support.
Statistics: Working knowledge of significance, power, sample size, and common pitfalls such as peeking and sample ratio mismatch.
Experimentation Platforms: Experience with a feature-flag or A/B testing platform (GrowthBook, Statsig, or close equivalents).
Conversion Copy & UX: Ability to write and critique conversion copy and page layouts, grounded in behavioural psychology.
AI Tooling: Active daily use of AI tools (Claude or equivalent) to accelerate concept, analysis, and prototype work.
Compliance: Familiarity with consumer protection rules for subscription products and marketing claims is a bonus.
Leadership Attributes
Holds a high bar for their own work and the team's - tests ship clean, documented, and correctly called
Constantly learns and adopts new tools and methods
Ambitious - driven to build large-scale products used by millions
Explains decisions clearly in writing - a hypothesis, a verdict, or a prioritisation call can be understood without a meeting
Communicates clearly and proactively in a remote, async environment
Ruby Labs operates within the CET (Central European Time) zone. Applicants from any country are welcome to apply for the position as long as they are located within approximately ± 4 hours of CET. This ensures optimal collaboration and communication during working hours.
BenefitsDiscover the perks of being part of our vibrant team! We offer:
Remote Work Environment: Embrace the freedom to work from anywhere, anytime, promoting a healthy work-life balance.
Unlimited PTO: Enjoy unlimited paid time off to recharge and prioritize your well-being, without counting days.
Paid National Holidays: Celebrate and relax on national holidays with paid time off to unwind and recharge.
Company-provided MacBook: Experience seamless productivity with top-notch Apple MacBooks provided to all employees who need them.
Flexible Independent Contractor Agreement: Unlock the benefits of flexibility, autonomy, and entrepreneurial opportunities. Benefit from tax advantages, networking opportunities, reduced employment obligations, and the freedom to work from anywhere. Read more about it here: https://docs.google.com/document/d/1nkrN76JlZkbKj9WSOhlT1_mni_CZeDkHdwfIjPXVwvk/preview?tab=t.0#heading=h.ndsdl4wapxtt
Be part of our fast-growing team and seize this excellent opportunity for personal and professional growth!
Interview ProcessAfter submitting your application, we conduct a thorough review which typically takes 3 to 5 days, but may occasionally take longer due to the volume of applications received. If we see a potential fit, we proceed with the following steps:
Recruiter Screening (40 minutes)
Technical Interview (60 minutes)
Final Interview (60 minutes)
At Ruby Labs, we move fast, aim high, and expect the same from our team. We’re not here to play small—we’re here to build, grow, and win. That means we look for people who are ambitious, driven, and ready to give their best every single day.
This is a place for individuals who thrive under pressure, embrace challenges, and see opportunity in every obstacle. If you’re hungry to achieve, motivated by impact, and want to grow at the speed of your own ambition, Ruby Labs offers the platform to make it happen.
Here, effort is matched with reward. We recognize those who go all in and deliver results, and we create space for people who want more—more responsibility, more growth, and more success.
#LI-Remote
Skills Required
- 3+ years running A/B tests for a D2C subscription or consumer web product, with attributable results
- Hands-on proficiency with Mixpanel or an equivalent product analytics platform, including funnel building, segmentation, and cohort analysis
- Working knowledge of statistical significance, power, sample size, peeking, and sample ratio mismatch
- Experience with GrowthBook, Statsig, or an equivalent feature-flag or A/B testing platform
- Ability to write and critique conversion copy and page layouts using behavioral psychology
- Active daily use of AI tools such as Claude or equivalent
- Familiarity with consumer protection rules for subscription products and marketing claims
What We Do
Ruby Labs is a leading tech company that creates innovative consumer products across the health, education, and entertainment sectors. Our journey began in 2018 in London, UK, as a collaboration between two friends with extensive expertise in business, technology, and marketing. From the start, our vision has been to build a world-class tech company that develops category-leading products used by millions of users worldwide. We aim to create easily accessible platforms that offer engaging and valuable experiences across various aspects of people's lives. Since our launch, we've successfully brought seven consumer products to the global market, each addressing unique needs in health, education, or entertainment.






