Senior iOS Engineer

About Customer.io

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, Swift, Kotlin, TypeScript, Dart and AI power our SDKs and help us ship fast and scale with confidence.

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 care how your systems power real customer value—and how to make them better.

A healthy disregard for “the way things are done.”

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

What You'll Do

• Design and build multi-platform SDKs that are stable, performant, and easy to integrate.
• Drive architecture, testing, and release workflows. Guide technical strategy and make long-term bets.
• Push our SDKs forward. Shape public APIs, adopt new platform capabilities, and ensure integrations stay current.
• Support external developers by providing thoughtful guidance and helping resolve technical issues quickly and clearly.
• Write great documentation. From tutorials to reference material, you’ll help make our SDKs accessible to teams of all sizes.
• Prototype with AI tools and explore new ways to streamline development and integration.

What We're Looking For

• 7+ years of mobile development experience, with a strong foundation in native iOS.
• Demonstrated experience designing and shipping SDKs used by third-party developers.
• Comfort working across mobile platforms and frameworks, with an eye toward developer ergonomics on each.
• Strong API design sensibilities. You prioritize clarity, usability, and long-term maintainability.
• You understand and balance the needs of marketers and mobile developers.
• You're helpful, clear, and responsive when working with external developers or unblocking teammates.

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.

See full benefits here →

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 the hiring managers. We’ll explore topics like ownership, product thinking, and collaboration.
• Coding Interview (60 mins) - Pair with engineers to review and improve a code sample. We’ll focus on your thought process, technical decisions, and how you collaborate in real time.
• Technical Deep Dive (60 mins) - A structured discussion of a project and how you approach real-world engineering problems.

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.