Fullstack SDK Engineer

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 developer using your tools, not just an engineer building them. You care about API design, developer experience, and everything in between.

A healthy skepticism for “the way things are done”

You bring rigor and creativity. Best practices matter - but never more than forward motion., * Build and evolve Customer.io’s SDKs across platforms - including Android, iOS, Node, and Go - and the developer tools that support them

• Lead SDK initiatives end to end: set technical direction, write the code, manage the release, and own the outcome
• Improve SDK delivery infrastructure - CI, automated testing, versioning, publishing, and release processes - so shipping is reliable and low-friction
• Partner closely with product and design to turn loosely defined goals into a great developer experience
• Use AI agents to make multi-file changes across unfamiliar codebases and languages by scoping the work, writing the prompt, and verifying the output
• Bring strong customer empathy to the role - understanding what the engineers integrating with our SDKs actually need, and occasionally engaging directly with them, * Hiring Manager & AI Skills Interview (60 mins) - We’ll explore ownership, autonomy, and collaboration, then dig into how you actually use AI in your day-to-day workflow.
• Practical AI-Enabled Coding Round (60 mins) - A live, collaborative session where you’ll extend a sample SDK using AI tools. Wwe want to see how you think and work with AI as part of your process.

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., This should be the location you plan to consider your primary residence and are legally authorized to work in. Were you referred to this position by a current or former team member? If so, please list their name below.*

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If you have not, please answer N/A Do you currently work for, or have you worked for, a company or partner agency that uses Customer.io in the past 2 years?* Select… If you answered “Yes” to the question above, please list the company or partner agency name(s).*

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As a remote company, we hire across many locations, but we do have policies and team needs that influence where we can support employment. Because of this, we’re not able to offer visa sponsorship or relocation support at this time.

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For government reporting purposes, we ask candidates to respond to the below self-identification survey. Completion of the form is entirely voluntary. Whatever your decision, it will not be considered in the hiring process or thereafter. Any information that you do provide will be recorded and maintained in a confidential file.

As set forth in Customer.io’s Equal Employment Opportunity policy, we do not discriminate on the basis of any protected group status under any applicable law. Gender Select… Are you Hispanic/Latino? Select… Race & Ethnicity Definitions

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A “disabled veteran” is one of the following: a veteran of the U.S. military, ground, naval or air service who is entitled to compensation (or who but for the receipt of military retired pay would be entitled to compensation) under laws administered by the Secretary of Veterans Affairs; or a person who was discharged or released from active duty because of a service-connected disability.

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• Expert-level competency in at least one established programming language, with strong software design and API design fundamentals
• Experience building and evolving mature, production-quality software, with a clear understanding of how systems fit together and how other developers consume them
• Exceptional fluency with current LLMs and agentic coding tools (e.g., Claude, Cursor, Codex) - using AI to understand unfamiliar codebases, work across languages, and run things in parallel or autonomously
• High autonomy in ambiguous environments - you clarify the problem, validate its value, and drive implementation without close direction
• Strong written and verbal communication, with the ability to explain technical decisions and tradeoffs clearly
• Ability to work effectively across multiple languages and stacks; prior experience in every language we support (Swift, Kotlin, Node, Go) is not required

Nice to have: experience building external-facing SDKs, APIs, or developer tools; experience owning CI, testing, versioning, or release infrastructure; or forward-deployed engineering experience.

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.