Senior Software Engineer, Ledgering

Role Description

Ledgering is the accounting core that other teams at Block build on. We keep the authoritative records of balances for Square and Cash App, along with the transactions and settlement that move that money. As a Senior Software Engineer on the team, you will build and operate the systems of record for balances and transactions, the settlement orchestration that decides how sellers and customers get paid, and the automated treasury systems that position Block's own cash. At Block's transaction volume, this work has direct, measurable impact on financial accuracy and on the trust merchants and customers place in us.

• Design, build, and operate the balance and transaction systems of record that serve as the financial source of truth for millions of merchants and customers.
• Build settlement orchestration that determines how account holders get paid: schedules, amounts, deposit methods, and withholdings.
• Develop self-serve ledgering APIs with durable semantics and clear contracts, so partner teams can stand up a new balance or transaction type in about a day instead of waiting weeks on custom integration work.
• Emit balance and settlement data that downstream finance, reconciliation, and reporting teams can trust, against agreed data contracts.
• Design and implement reliable, high-volume distributed transaction-processing systems, making thoughtful tradeoffs between consistency and availability when both are not possible.
• Drive convergence across a large portfolio of financial services: consistent transaction and balance models, shared workflow tooling, and predictable integration patterns.
• Operate tier-0 and tier-1 financial systems against published SLOs, and debug production issues across services and multiple levels of the stack in a high-reliability environment.
• Work AI-natively: use AI agents throughout the development lifecycle, and build agents and automation that reduce operational toil across our services.
• Lead complex projects end to end, breaking the work into components and milestones that other engineers can pick up.
• Mentor other engineers and contribute to the technical direction of the team.
• Work with engineers, product managers, and finance and treasury stakeholders across the company to ship new capabilities at scale.

Qualifications

• A minimum of 8 years of related experience with a Bachelor's degree; or 6 years and a Master's degree; or a PhD with 3 years experience; or equivalent experience.
• Experience designing and operating distributed, high-throughput, fault-tolerant services, with a strong understanding of consistency, idempotency, and failure handling.
• Experience building money-movement systems such as ledgers, double-entry accounting, settlement, or treasury, or the curiosity and drive to build deep expertise in the domain.
• Proficiency in at least one major programming language (for example Java, Kotlin, or Go) and strong SQL.
• Experience leading complex, ambiguous projects across multiple engineering teams and driving clear next steps in areas without clear ownership.
• High standards for software architecture and engineering practices, including maintainable and testable code, CI/CD, and observability, in a complex, high-stakes financial environment.
• Proficiency in using AI tools throughout the software development lifecycle to improve engineering productivity, problem solving, and software delivery.
• Strong written and verbal communication skills.

Requirements

• Technologies We Use and Teach:
• Java, Kotlin, Python
• AI agents and tooling across the development lifecycle, including AMP, Codex, Claude, Goose and MCP
• Temporal, Protocol Buffers, jOOQ, GraphQL
• MySQL, Aurora, Vitess, Databricks, Snowflake
• AWS, Kubernetes, Terraform, Datadog

Benefits

• Remote work
• Medical insurance
• Flexible time off
• Retirement savings plans
• Modern family planning