Software Engineer, SDK

About Keycard At Keycard , we’re building identity & access infrastructure for the agent-native era —where software isn’t static, but a dynamic, constantly changing system of AI agents working on behalf of people and businesses to complete dynamic tasks at runtime. Our mission is to unlock the agent economy by empowering developers and enterprises with the secure, scalable foundations they need to build, deploy, adopt, and trust agentic applications . To do this, we’re building the real-time, in-band, contextual guardrails required to transition from human-driven to truly autonomous and agentic workflows that give users, builders, and security teams the confidence and control they need to bring agents out of the lab and into production. At our core, we’re laser-focused on delivering a delightful, best-in-class developer experience that gives them the tools they need to create category-defining applications and experiences while giving platform and security teams the security, scalability, visibility, control, and enablement they need to accelerate their organizations journey to becoming agent native. We’re a small, distributed team of repeat founders and builders, with backgrounds from Snyk , Auth0 , HashiCorp , and Heroku . Joining Keycard now means helping define not just our technology, but also the culture and company we’re building together—during a once-in-a-generation platform shift. The role We're hiring an engineer to join the team that builds and owns the Keycard Agent SDK — the libraries that bring trust, governance, and telemetry to AI agents in production. Keycard is a control plane for agents: policy enforcement, identity propagation, audit logging, and runtime governance. The SDK is how developers use it. It needs to work across languages (Go, Python, TypeScript, Rust), agent frameworks, and deployment patterns (cloud, edge, hybrid). You'll build the SDK libraries, maintain compatibility with upstream frameworks, contribute to open protocol work (MCP, A2A), and advocate for what agent developers actually need. You'll work directly with founders, product, and the systems engineers building the underlying services. What we're looking for You follow the agent ecosystem closely — you build with these tools and have opinions about what works, what doesn't, and when to use which framework. Strong systems engineering instincts. You write tests, think about backwards compatibility, version correctly, and care about API surface area. You've built libraries or SDKs that other developers depend on. You understand the difference between building a product and building a tool others build products with. You work across multiple languages without treating any of them as second-class. Strong candidates may also have Experience with plugin systems, provider architectures, or marketplace/ecosystem engineering (Terraform providers, VS Code extensions, Stripe integrations, etc.) Contributions to open source agent frameworks or protocols Background in identity/auth protocols (OIDC, OAuth, mTLS) at the library level Experience with code generation tools (OpenAPI, protobuf, smithy) for multi-language SDK maintenance What We Offer Build at the Frontier: Work every day at the frontier of agent-native systems — shipping, inventing, and iterating on technology that hasn’t been built before. You’ll be given huge autonomy, the opportunity to gain mastery, and the chance to work in a team that holds each other accountable to succeed. Truly Agent-Native Culture: At Keycard, we don’t just enable others to adopt agents — we use them ourselves to build. You’ll help shape an organization that embeds AI into its foundation as an enduring competitive advantage. Compensation With Upside: Market-competitive salaries and generous equity packages (4-year vest, 1-year cliff) give you the security to focus on building — and the asymmetric upside of ownership in a company chasing a category-defining mission. Comprehensive Benefits & Recharge: Health, dental, vision, and paramedical coverage for you and your family, plus 4 weeks vacation, 11 statutory holidays, and 1 volunteer day annually. We encourage at least 2 weeks off each year to fully recharge. Tools That Keep You Ahead: A new MacBook Pro, a $500 stipend for peripherals, and the best AI tools available so you can work at the forefront of agent-native workflows. Remote-First Flexibility: We are a remote-first team prioritizing asynchronous collaboration, with hiring focused in North and South America. Work where you’re strongest — we just want the best. Why Join Us? Keycard is building the fundamental unlock for the next generation of software: enabling truly secure and trusted agentic applications. Under the hood, we’re building a new identity and access control stack to take us from a world of static, user-focused, long-lived roles and credentialing to one of mixed machine & human interaction that is dynamic, contextually-scoped, and short-lived. By joining as an early employee, you’ll have the opportunity to help curate a culture of iterative craftsmanship, disciplined design, empowerment to own meaningful problems, and consistent high-quality delivery with real impact. You’ll collaborate with the founders and investors who have championed identity, security, and developer tools from seed to scale with companies like Snyk, Auth0, and Heroku. If you’re energized by tackling complex distributed systems and want to advance both developer productivity and security posture , with a hunger to learn, have an impact, and move quickly with determination we’d love to explore how you can help us shape the future of software.