Senior Software Engineer (Java) - API Excellence

About the Team

Adyen's Single Platform is a cornerstone of our business, and we empower our teams with autonomy to drive its growth. This dynamic environment has led to a rich and evolving API ecosystem.

To build on this success, we are continually investing in the developer experience, enhancing the consistency and ease of use across all our APIs and SDKs. This ongoing commitment makes integration faster for our customers and accelerates our own pace of delivering new features.

The API Excellence team is being formed at a critical juncture, with the rise of AI-assisted development, to address these challenges and create a single platform API experience that empowers developers—both human and AI—to build with speed and confidence. This team is central to that vision.

• The Scope: You will oversee the architecture not just for our core APIs, but also for our client-facing SDKs across Java, C#, Node.js, Go, Ruby, Python, and PHP

• The Mission: We are defining the "Golden Path" for API development, building the tooling that empowers developers—both human and AI—to build with speed and confidence.

What You Will Do

• Architect the Future: Design the "One Platform" strategy, moving us toward unified versioning and consolidated SDKs to reduce merchant integration time.

• Drive Governance & Influence Leadership: You will act as a key advisor to our API design guild and senior leadership. You will provide critical feedback on technical feasibility and roadmap risks, ensuring that high-level strategy aligns with ground-level engineering reality.

• Force Multiplier: You scale your impact through systems, not just effort. You codify your expertise into linter rules, automated guides, and architectural standards, building the guardrails that enable hundreds of internal developers to ship consistent, high-quality APIs autonomously.

• Mentorship: You are a dedicated teacher and advocate. You engage deeply in code reviews and design discussions not just to catch errors, but to elevate the team's technical bar and foster a supportive, learning-driven culture.

• Bridge the AI Gap: Lead our R&D into AI-assisted integration, building Model Context Protocol (MCP) servers that allow AI agents to navigate our API specs and SDKs.

• Build High-Leverage Tooling: Develop the linter rules, CI/CD gates, and upgrade tooling that automatically steer hundreds of internal developers toward compliance.

Who You Are

Key Qualifications

• Experience & Domain Knowledge: 7+ years of engineering experience with a strong background in Platform Engineering, Developer Experience (Dev Ex), or API Infrastructure. You have a deep understanding of REST and OpenAPI, specifically regarding the challenges of managing breaking changes and versioning at scale.

• Architectural Strategy: You understand the nuance between "loosely coupled" and "highly aligned" systems and can design for both. You view APIs as a Product, understanding that a broken contract is a broken customer experience.

• Polyglot Versatility: Because you will oversee the architecture for our client-facing SDKs, you are comfortable navigating and reviewing code across multiple languages (e.g., Java, C#, Node.js, Go, Ruby, Python, or PHP). You do not need to be proficient in all, but you must be able to guide their architectural standards and use AI tooling to your advantage. Asking the right questions is much more important than having the answers.

• Strategic Influence: You excel at driving technical change without direct authority. You can confidently articulate technical tradeoffs to Senior Leadership and explain to Product Managers why a specification must change.

• Foundational Pragmatism: You balance innovation with stability. You are committed to executing foundational improvements—such as standardizing error messages and addressing technical debt—to enable long-term AI capabilities.

• Mentorship: You take a hands-on approach to leadership, engaging deeply in technical discussions to foster a supportive, learning-driven environment.

Bonus Skills

• Tooling & Automation: Experience building developer tools, SDKs, or maintaining automated CI/CD quality gates/linters is a strong plus.

• AI-Native Design: Experience with (or a keen interest in) designing APIs for AI-assisted integration, including concepts like Model Context Protocol (MCP) and optimizing error messaging for AI agents.

• Emerging Standards: A growth mindset toward industry trends such as GraphQL or Arazzo Specs, with the pragmatism to evaluate their fit for the organization.