Senior Fullstack SDK Engineer
Customer.ioBase Salary
$150k - $200k/yr
Responsibilities
- Build and evolve Customer.io SDKs across Android, iOS, Node, and Go, plus the developer tools that support them.
- Lead SDK initiatives end to end by setting technical direction, writing code, managing releases, and owning outcomes.
- Improve SDK delivery infrastructure, automated testing, versioning, publishing, and release processes.
- Partner with product and design to turn loosely defined goals into effective developer experiences.
- Use AI agents to make multi-file changes across unfamiliar codebases and languages, including scoping work, writing prompts, and verifying results.
- Understand the needs of engineers integrating with the SDKs and occasionally engage directly with customers.
Requirements
- 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 and understanding how systems fit together and are consumed by other developers.
- Exceptional fluency with current LLMs and agentic coding tools such as Claude, Cursor, and Codex.
- Ability to operate autonomously in ambiguous environments and drive implementation without close direction.
- Strong written and verbal communication skills, including the ability to explain technical decisions and tradeoffs.
- Ability to work effectively across multiple languages and technology stacks; prior experience with every supported language is not required.
- Experience with external-facing SDKs, APIs, developer tools, CI, testing, versioning, release infrastructure, or forward-deployed engineering is preferred.
Benefits
- 100% coverage of medical, dental, vision, mental health, and supplemental insurance premiums for employees and their families.
- 16 weeks of paid parental leave.
- Unlimited paid time off.
- Remote work and wellness stipends.
- Professional development budget.
- Remote work support is provided, with virtual interviews conducted via Zoom.
Categories
About Customer.io
Create personalized customer journeys that engage and convert with our versatile customer engagement platform. Scale, flex, and innovate at your own pace. Because when powered by data, your messages lead to meaningful relationships. Deliver meaningful interactions: Make every message relevant by building unique customer interactions across mobile and web using email, in-app messages, SMS, and push notifications. Designed to help you scale: Manage all your messaging in one place with a platform that seamlessly integrates with the tools you use every day. Data without limits: Put an end to data silos by easily moving real-time data from source to destination and crafting campaigns with unlimited profile attributes, events, or actions.