Senior Fullstack Engineer

We are seeking talented Senior Fullstack Engineers to join our growing engineering team!

You’ll work on challenging problems, building scalable, robust services and user interfaces that drive the future of customer engagement technology. As our next great teammate, you'll blend your expertise across both backend and frontend systems, to directly impact the experience of a wide variety of customers, from startups to global enterprises, and help shape the features and infrastructure needed for our product to flourish.

Some things you'll do...

• Design and develop high-performance, scalable services in Go and user interfaces in JavaScript (React & Ember), driving critical workflows that empower businesses to engage with their customers.
• Collaborate cross-functionally with incredible partners across Product, Design, and Engineering to shape and implement features that enhance our platform and deliver seamless, intuitive experiences for our users.
• Own the entire development lifecycle, from technical design through implementation and deployment, ensuring reliability, maintainability, and performance at scale.
• Lead by example, mentoring your peers and contributing to a culture of shared knowledge, continuous learning, and technical excellence across the team.
• Identify high-impact opportunities to improve both backend services and frontend interfaces, turning complex challenges into elegant, user-friendly solutions.
• Influence product direction through technical insights, proactively collaborating with others to prioritize features that matter most.

What we're looking for...

• 7+ years of professional experience in full-stack development, with a strong portfolio showcasing complex web applications and distributed systems.
• Professional experience with TypeScript combined with advanced knowledge of JavaScript, CSS, and HTML.
• Experience in modern JavaScript frameworks. (Bonus if you have experience with Ember.js or React)
• Proficiency in backend technologies, ideally with Go or another strongly-typed language such as Java, Kotlin, or TypeScript. 
• Experience designing and maintaining scalable APIs and services with relational (e.g., PostgreSQL or MySQL) or NoSQL databases.
• A cloud-native mindset. Deep experience working in AWS, GCP, or Azure, or tools like Docker and Kubernetes are nice to have.
• Passionate about building high-quality, testable code using unit, integration, and end-to-end testing to ensure system stability and performance.
• A track record of collaborating effectively in a distributed team environment, with strong written and verbal communication skills and a commitment to mentoring others.
• Problem-solving expertise, with the ability to transform complex technical challenges into simple, elegant solutions that delight users.
• A DevOps approach to development, with experience in CI/CD pipelines, infrastructure automation, and monitoring production systems.
• Demonstrated ability to influence product direction and contribute technical insights that help drive business value.

About Customer.io

Our mission at Customer.io is to power automated communication that people like to receive. Today over 7,600 internet businesses use Customer.io to manage, send, and track the performance of emails, SMS, push notifications, and in-app messages. Unlike typical marketing platforms, Customer.io helps businesses increase relevance by using behavioral data: what people do or don’t do when logged in to a web or mobile app.

We are offering a starting salary of $160,000 - $184,000 USD (or equivalent in local currency) depending on experience and subject to market rate adjustment.

Benefits at Customer.io include:

• Unlimited PTO - we encourage at least 20 vacation days (in addition to holidays and sick days) so that you can unwind, unplug, and recharge
• 16 weeks paid parental leave (including adoption and foster care)
• 100% paid insurance premiums for you and your dependents
• 401k retirement matching - up to 5% dollar-for-dollar match to retirement contributions
• $1,500 annual healthy lifestyle budget (for gym memberships, classes, fitness equipment)
• $250/monthly Remote Work Stipend to be used for home internet, cell phone, and other miscellaneous remote work costs
• $300/month co-working space rental reimbursement
• $2,000/yearly professional education budget for conferences, courses, workshops, books, etc.
• $1,500 home office budget to make sure your working space is ergonomic and just what you need to do your best work!
• One month sabbatical after five years at Customer.io
• We also have opportunities to meet in person with your peers throughout the year

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.

Join us!

Check out our careers page for more information about why you should come work with us! We are passionate about our core values of Empathy, Transparency, Responsibility, and Awkwardness and are looking for new coworkers to share and build that passion!

How to apply

Apply at the link below and tell us why you're interested in the position! ****We plan to respond to all applicants with a status update about your application.

Here's what you can expect from our hiring process:

1. 30 minute video call with a Recruiter
2. 60 minute Technical Interview
3. Take Home Assignment + 60 minute Assignment Review Call
4. Final Interview with Hiring Manager