Keycard Labs - Software Engineer, SDK

• 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