Senior Frontend Engineer

customer.io

Location: Americas Remote
Job Type: full-time
Salary: $150,000 - $200,000 USD
Posted: July 18, 2025

Job Description

Over 7,500 companies - from scrappy startups to global brands - use our platform to send billions of emails, push notifications, in-app messages, and SMS every day. Customer.io powers automated communication that people actually want to receive.

We help teams send smarter, more relevant messages using real-time behavioral data. Under the hood: Go, React, Ember and AI help us ship fast and scale with confidence.

We’re looking for thoughtful, experienced frontend engineers who love designing delightful user interfaces and care deeply about the details. You’ll build the tools that empower our customers to create better experiences for theirs.

What We Value

Ownership
You own problems end to end. You move fast, act like an owner, and thrive in ambiguity. You've led complex projects before—whether officially or not—and you're ready to do it again.

Engineers with product taste

You think like a user, not just an engineer. You advocate for clean, intuitive design and love turning complex workflows into seamless, elegant interfaces.

A healthy skepticism for “the way things are done”

You bring rigor and creativity. Best practices matter - but never more than forward motion.

What You’ll Do

Build high-quality, accessible UIs in React and Ember that power core user workflows
Collaborate with engineers and designers to bring new features to life
Continuously improve our design system and frontend architecture for performance and scalability
Share knowledge and raise the bar through sharing your progress publicly with the team
Leverage AI tools to prototype, move faster, and make better decisions

What we're looking for

7+ years of frontend experience building complex applications
Fluency in JavaScript, HTML, CSS, and modern frameworks like React (Ember.js is a bonus, or you're open to learning)
Care for polish, performance, accessibility, and the full user experience
Strong product thinking, with an understanding of how your code fits into the bigger picture
A bias for action over perfection, and pride in owning technical decisions

Compensation & Benefits

We believe in transparency. Starting salary for this role is $150,000 - $200,000 USD (or equivalent in local currency) depending on experience and subject to market rate adjustment.

We know our people are what make us great, and we’re committed to taking great care of them. Our inclusive benefits package supports your well-being and growth, including 100% coverage of medical, dental, vision, mental health, and supplemental insurance premiums for you and your family. We also offer 16 weeks paid parental leave, unlimited PTO, stipends for remote work and wellness, a professional development budget, and more.

Our Process

No gotchas, no trick questions - just a clear, human process designed to help both of us make an informed decision.

Application - We review everyone with care. Tell us why you're interested.
Recruiter Call (30 mins) - Let’s chat about what you’re looking for and how we work.
Behavioral Interview (60 mins) - Talk with one of our hiring managers. We’ll explore topics like ownership, product thinking, and collaboration.
Technical Interview (60 mins) - A conversation focused on your frontend experience.
Take-Home Assignment - Complete a short, realistic task similar to what you’d work on here.
Assignment Review Call (60 mins) - Walk us through your work and discuss tradeoffs, priorities, and how you’d iterate.

All final candidates will be asked to complete a background check and employment verifications as part of our pre-employment process.

Customer.io recognizes the stifling impact of systemic injustice on diverse communities. We commit to using our influence to increase inclusion and equity within the tech industry. We strive to build an inclusive team culture, implement bias-free hiring practices, and develop community partnerships to expand our global impact.

Zoom is the only video conference platform that we use, virtual interviews will be conducted using the video capability (i.e., not via the chat), and offers will be extended in writing on official Customer.io letterhead. Please be vigilant in all of your job search activity, and if you have any questions please contact jobs@customer.io.

Join us!

We believe in empathy, transparency, responsibility, and, yes, a little awkwardness. If you’re excited by what you read and want to build software that makes communication better for everyone—apply now.

🎯 Who is this job for?

This role is perfect for a Senior Frontend Engineer with 7+ years of experience, strong skills in JavaScript, HTML/CSS, and frameworks like React or Ember. Ideal candidates care about UI polish, performance, and accessibility, and enjoy collaborating closely with designers to create user-centric interfaces. It suits engineers who think like product owners, value autonomy, and thrive in fast-moving, remote-first environments.

💬 Potential Interview Questions

How do you approach building accessible and performant UIs in React?
I follow accessibility standards (WCAG), use semantic HTML, ARIA roles, and focus on optimizing rendering with techniques like memoization and code splitting to enhance performance.
Describe your experience with frontend architecture for scalable applications.
I design modular, reusable components, leverage state management solutions (like Context or Redux), and apply lazy loading and micro-frontends where appropriate to ensure scalability.
How do you incorporate product thinking into your frontend development?
I align closely with user needs, collaborate with designers and product managers, and focus on delivering intuitive, seamless experiences that solve real user problems rather than just coding features.
What is your strategy for owning end-to-end frontend projects?
I take responsibility from requirement analysis through deployment, including writing clean code, testing thoroughly, performing code reviews, and monitoring production for issues.
Have you used AI tools in your frontend workflow? How?
Yes, I use AI-assisted code completion tools for faster prototyping and debugging, and for generating ideas to improve UX design or optimize code.
What challenges have you faced with Ember.js or React in complex applications?
Challenges include managing state complexity, optimizing rendering performance, and maintaining consistent UI behavior across browsers, all mitigated by good architecture and testing.
How do you ensure continuous improvement of design systems and frontend codebases?
By regularly refactoring, updating dependencies, enforcing coding standards, and collaborating with design teams to keep UI components consistent and reusable.
Explain how you handle collaboration in distributed or remote teams.
I maintain clear communication via async tools (Slack, email), schedule regular check-ins, document decisions well, and use version control and code reviews to ensure smooth collaboration.
How do you balance between speed of delivery and code quality?
I prioritize MVP delivery with clear scope, use feature flags for iterative releases, and maintain a robust testing suite to safeguard code quality without slowing progress.
What’s your process for receiving and incorporating feedback?
I actively listen, ask clarifying questions, reflect on the feedback, and iterate on my work while maintaining open communication with stakeholders to align expectations.

📋 Job Summary

Customer.io is hiring a Senior Frontend Engineer (remote Americas) to build polished, accessible UIs in React and Ember that power core user workflows for over 7,500 companies worldwide. With 7+ years of frontend experience, you’ll own complex projects end-to-end, collaborate closely with designers and engineers, and continuously improve frontend architecture and design systems. This role values product thinking, technical ownership, and a bias for action, offering a transparent salary range of \$150K–\$200K plus a comprehensive benefits package including full medical coverage, parental leave, unlimited PTO, and professional development support.