Software Engineer, SDK

ABOUT KEYCARD At Keycard, we're building identity and 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. Keycard gives every agent a verified identity and issues short-lived, task-scoped credentials at runtime, so agents can only do what they were asked to do, and every action is fully auditable. We're backed by a16z, Boldstart, and Acrew, and our founding team built and scaled Snyk, Auth0, HashiCorp, and Heroku. 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.