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Software Engineer, Payment Interfaces

Block· 10414 Engineering - Fintech Platform
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Hybrid (Bay Area, CA)$196.1k - $326.8kFull-timePosted 4w ago

About the role

Role focused on designing, building, and operating customer-facing payment APIs and services powering Square, Cash App, and Afterpay, with emphasis on high-volume, reliable payment systems and AI-assisted tooling.

Responsibilities

  • Design, build, maintain, and scale customer-facing payment APIs with clear contracts, predictable behavior, and compatibility that developers can rely on.
  • Lead complex projects end to end: clarify requirements, evaluate trade-offs, plan incremental delivery, and own testing, rollout, and ongoing maintenance.
  • Operate critical payment systems serving worldwide traffic. Participate in the team’s on-call rotation, investigate incidents, and follow through on fixes that improve reliability.
  • Improve performance, observability, fault tolerance, and security. Use automation to reduce repetitive operational work and make systems safer to change.
  • Work with product and engineering partners across Block to turn payment requirements into reusable capabilities.
  • Use AI-assisted tools for design, implementation, testing, and debugging. Critically evaluate their output and help teammates adopt approaches that improve quality and delivery.
  • Shape technical decisions within the team and develop others through design reviews, code reviews, documentation, and mentoring

Qualifications

  • Experience building, maintaining, and scaling customer-facing financial or payment APIs, together with a strong understanding of payments.
  • Experience designing and operating high-volume, highly available distributed systems where correctness, security, and reliability matter.
  • Understanding of payment API concerns such as idempotency, retries, asynchronous processing, backward compatibility, and handling partial failures without compromising financial correctness.
  • Record of leading complex engineering projects from unclear requirements through production, making technical trade-offs, and coordinating work with partner teams.
  • Experience diagnosing production issues and improving systems through monitoring, incident response, and preventive engineering.
  • Fluency with AI-assisted engineering tools and the judgment to validate generated code, protect sensitive data, and recognize when deeper investigation is needed.
  • Clear written communication and experience helping other engineers develop their technical skills.
  • Bachelor’s degree with 8+ years of related experience; or 6 years with a Master’s; or PhD with 3 years experience; or equivalent experience

Skills

Required:Payment APIsDistributed systemsIncident response and monitoringCommunication and mentoring
Nice to have:AI-assisted engineering

Benefits

  • Remote work
  • medical insurance
  • flexible time off
  • retirement savings plans
  • modern family planning
  • other benefits at Block
Last updated Sep 23, 2026. Interested? Apply on the company site.
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About Block

Block builds technology to increase access to the global economy.

Made up of Square, Cash App, Afterpay, TIDAL, Bitkey, and Proto, Block, Inc. builds technology to increase access to the global economy.

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