Senior Software Engineer, Developer Experience

Block; New York (NY); Hybrid; USD 218,000 - 327,000; Full time

Benefits offered by this job

Remote work

Medical insurance

Flexible time off

Retirement savings

Family planning benefits

Job summary

Block is seeking a Developer Experience Engineer to enhance our massive monorepos, driving framework upgrades, language migrations, and dependency updates while minimizing disruption to product teams. You will shape agentic workflows and improve build/tooling, enabling faster, safer software evolution across the organization.

You will lead migrations, mentor engineers, and partner with teams to measure impact, set direction, and ensure code health at scale in a dynamic, remote-inclusive

Qualifications

• 7+ years in large, complex codebases
• Experience with upgrading application/frameworks
• Led migrations or large refactors
• Able to read unfamiliar code quickly
• Understanding of agentic loops and safety
• Strong communication and collaboration

Responsibilities

• Lead and execute large-scale changes across the codebase with minimal disruption to product teams
• Design and evolve agentic loops: plan, act, verify, iterate for safe, reliable AI-driven changes
• Identify bottlenecks in the developer workflow and fix root causes
• Improve build tooling and CI performance
• Build guardrails, tests, and automation for large changes
• Partner with product engineering to understand pain points and measure impact
• Set technical direction and mentor other engineers on migration strategy and tooling

Skills

Large codebases

Framework migrations

Codebase refactors

Agentic loops

Cross-team collaboration

Strong communication

Tools

Bazel

Codemods

CI/CD tooling

Gradle

Job description

Block is one company built from many blocks, all united by the same purpose of economic empowerment. The blocks that form our foundational teams — People, Finance, Counsel, Hardware, Information Security, Platform Infrastructure Engineering, and more — provide support and guidance at the corporate level. They work across business groups and around the globe, spanning time zones and disciplines to develop inclusive People policies, forecast finances, give legal counsel, safeguard systems, nurture new initiatives, and more. Every challenge creates possibilities, and we need different perspectives to see them all. Bring yours to Block.

The Role

Our engineers are only as effective as the tools, codebase, and workflows around them. As a Developer Experience Engineer, you’ll make our large, evolving codebase easier to build, change, and reason about, for both human developers and AI agents.

You will be responsible for the developer experience in our largest monorepos: building tools for and driving framework and language migrations, keeping dependencies healthy, improving build and test infrastructure, and shaping how agentic workflows operate in our development process. This is a high-leverage role. Every improvement you ship multiplies across the whole engineering organization.

What you’ll do

• Lead and execute large-scale changes across the codebase, including framework upgrades, language migrations, and dependency updates, with minimal disruption to product teams
• Design and evolve agentic loops: the plan, act, verify, and iterate cycles that let AI agents do real engineering work safely and reliably
• Identify friction in the developer workflow (slow builds, flaky tests, confusing abstractions) and fix the root causes
• Improve build tooling and CI performance, including work with Bazel or a comparable build system
• Build the guardrails, tests, and automation that make large, automated changes safe to land
• Partner with product engineering teams to understand their pain points and measure the impact of your work
• Set technical direction and mentor other engineers on migration strategy, tooling, and codebase health

What we’re looking for

Required

• Significant experience (typically 7+ years for Senior, 10+ for Staff) working in large, complex codebases
• Deep experience with application or platform frameworks, including upgrading them and managing their evolution over time
• Track record of leading migrations or large refactors, from planning through rollout
• Comfort navigating unfamiliar code quickly and making sound changes across many teams’ areas
• A solid understanding of agentic loops (tool use, context management, verification, failure handling) and a genuine willingness to keep investing in and evolving them as the field changes
• Strong communication skills and the ability to build trust with teams whose code you’re changing

Nice to have

• Hands-on experience with Bazel or similar build systems (Buck, Pants, Nx, Gradle, etc.)
• Experience with codemods, AST-based tooling, or automated refactoring at scale
• Background in CI/CD, test infrastructure, or developer productivity metrics
• Experience building or integrating LLM-based coding tools into engineering workflows
• Open source contributions to build tools, frameworks, or developer tooling

Block takes a market-based approach to pay, and pay may vary depending on your location. U.S. locations are categorized into one of four zones based on a cost of labor index for that geographic area. The successful candidate’s starting pay will be determined based on job-related skills, experience, qualifications, work location, and market conditions. These ranges may be modified in the future.To find a location’s zone designation, please refer to thisresource. If a location of interest is not listed, please speak with a recruiter for additional information.

Zone A:: $217,800 USD - $326,800 USD

Zone B: : $207,000 USD - $310,400 USD

Zone C:: $196,100 USD - $294,100 USD

Zone D:: $185,200 USD - $277,800 USD

Use of AI in Our Hiring Process

We may use automated AI tools to evaluate job applications for efficiency and consistency. These tools comply with local regulations, including bias audits, and we handle all personal data in accordance with state and local privacy laws.

Contact us herewith hiring practice or data usage questions.

Every benefit we offer is designed with one goal: empowering you to do the best work of your career while building the life you want. Remote work, medical insurance, flexible time off, retirement savings plans, and modern family planning are just some of our offering.

Check out our other benefits at Block.

Block, Inc. (NYSE: XYZ) builds technology to increase access to the global economy. Each of our brands unlocks different aspects of the economy for more people.Squaremakes commerce and financial services accessible to sellers.Cash Appis the easy way to spend, send, and store money.Afterpayis transforming the way customers manage their spending over time.TIDALis a music platform that empowers artists to thrive as entrepreneurs.Bitkeyis a simple self-custody wallet built for bitcoin.Protois a suite of bitcoin mining products and services. Together, we’re helping build a financial system that is open to everyone.

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