Software Engineer, SDK

The role

You will own the libraries developers use to put Keycard in front of agents and MCP servers. You will design APIs, manage releases, and ensure consistent behavior across Python, TypeScript, Go, and Ruby.

What you will do

• Design APIs to keep authorization concepts and behavior consistent across languages.
• Implement safe defaults for token validation and signing-key outages.
• Track upstream MCP SDK major versions and framework integrations.
• Own releases for PyPI, npm, RubyGems, and Go modules.
• Manage the path from OpenAPI spec to generated clients.
• Improve developer experience through quick starts, examples, and documentation.
• Review pull requests from coding agents.

Required qualifications

• Shipped libraries or SDKs that other developers depend on and supported them through breaking changes.
• Kept one API consistent across at least two languages.
• Write idiomatic Python and TypeScript.
• Know OAuth 2.0 and OIDC at the library level: token verification, refresh, PKCE, and token exchange (RFC 8693).
• Managed versioning in the real world: peer dependency ranges, maintenance branches, and deprecations.
• Built framework integrations or protocol libraries.

Nice to have

• Code generation for multi-language SDKs: Stainless, Speakeasy, Fern, OpenAPI, or protobuf.
• Plugin or integration ecosystems, like Terraform providers, framework adapters, or editor extensions.
• Contributions to MCP, the A2A protocol, or open source agent frameworks.
• Edge runtimes like Cloudflare Workers, or durable execution like Temporal.
• Go or Ruby

Benefits

• Market-competitive salaries
• Generous equity packages (4-year vest, 1-year cliff)
• Health, dental, vision, and paramedical coverage for you and your family
• 4 weeks vacation
• 11 statutory holidays
• 1 volunteer day annually
• New MacBook Pro
• $500 stipend for peripherals
• Best AI tools available

About the company

Keycard is building identity and access infrastructure for the agent-native era. The founding team built and scaled Snyk, Auth0, HashiCorp, and Heroku.