Software Engineer, SDK
Keycard Labs13 days ago
Remote, United States or Remote, CanadaStaff+
Responsibilities
- Design consistent SDK APIs, including package interfaces, errors, credential types, and safe authentication defaults, across Python, TypeScript, Go, and Ruby.
- Maintain OAuth, token verification and refresh, PKCE, token exchange, MCP authentication, and agent-to-agent delegation capabilities.
- Track upstream MCP SDK and framework releases, manage compatibility and maintenance branches, and support breaking changes.
- Own package versioning, semantic releases, changelogs, deprecations, CI, and publishing to PyPI, npm, pkg.go.dev, and RubyGems.
- Manage the OpenAPI-to-Stainless generated-client workflow and fix issues in the API specification rather than generated code.
- Create quick starts, examples, documentation, and developer feedback loops for protected MCP servers.
- Establish appropriate trust, testing, and review practices for coding-agent contributions.
- Close TypeScript/Python SDK gaps, publish a cross-language API guide, deliver an upstream breaking-change update, and define the SDK roadmap.
Requirements
- Experience shipping and supporting developer-dependent libraries or SDKs through breaking changes.
- Experience keeping one API consistent across at least two languages, with idiomatic Python and TypeScript; Go or Ruby is a plus.
- Library-level knowledge of OAuth 2.0 and OIDC, including token verification, refresh, PKCE, and RFC 8693 token exchange.
- Practical experience with versioning, peer-dependency ranges, maintenance branches, and user-facing deprecations.
- Experience building with MCP and agent frameworks and using coding agents in daily development.
- Preferred experience with multi-language SDK code generation using Stainless, Speakeasy, Fern, OpenAPI, or protobuf.
- Preferred experience with plugin or integration ecosystems such as Terraform providers, framework adapters, or editor extensions.
- Contributions to MCP, the A2A protocol, or open-source agent frameworks are valued.
- Experience with Cloudflare Workers or Temporal is a plus.
Benefits
- Remote-first, asynchronous work with hiring focused in North and South America.
- Market-competitive salary and generous equity with a four-year vest and one-year cliff.
- Health, dental, vision, and paramedical coverage for the employee and family.
- Four weeks of vacation, 11 statutory holidays, and one volunteer day annually.
- New MacBook Pro, $500 peripherals stipend, and access to AI tools.
- Autonomous work on agent-native systems with opportunities for mastery and high-impact ownership.
Tech Stack
Categories
About Keycard Labs
Keycard is on a mission to redefine machine identity for the Internet—helping developers seamlessly connect people, agents, and services across networks, clouds, and applications. As AI-driven workflows grow more complex, Keycard’s dynamic, identity-based credentials ensure every agent and service operates with precise, contextual permissions. We’re building a global identity network backed by open protocols—empowering distributed systems to adapt, scale, and maintain cryptographically verifiable trust. By rethinking secret management from first principles, we aim to delight developers, meet the performance needs of platform engineers, and set a new standard for cloud-era security in an inclusive, collaborative environment.