Staff Software Engineer, Payments Acquiring

About the Role

The Financial Platform Acquiring team owns the acquiring side of card payments for Square, Cash App, and Afterpay. When someone pays with a card at a Square seller, through Afterpay, or uses a card to move money in or out of Cash App, our systems make sure that payment happens correctly, every time.

As a Staff Software Engineer on the Acquiring team, you will bring deep card payments experience to complex technical work on our roadmap. This includes expanding direct network and acquirer connections, delivering network mandates, and making card acceptance cheaper and more reliable. You will lead one or two projects at a time, build systems and tooling, debug at the message level, and turn payments expertise into durable capabilities.

This role works US West Coast hours, from our Bay Area or Seattle offices or remotely within the Pacific time zone.

Responsibilities

• Bring deep card acceptance expertise to the team, reading network specifications, ISO 8583 messages, mandates, and interchange rules, and turning them into sound engineering decisions.
• Own the technical direction of your projects from design through production rollout, and lead the engineers working on them.
• Partner with technical leads, product and finance operations partners, and stakeholders across Square, Cash App, and Afterpay.
• Stay deeply hands-on: write production code, build testing and certification tooling, analyze network messages, review designs and code, and debug issues down to the protocol and field level.
• Make and defend technical calls on routing, retries, and processing cost, backed by data on authorization rates and fees.
• Establish shared frameworks, standards, tooling, and practices to make payments expertise durable across the team.
• Raise the technical capability of engineers around you through design guidance, code reviews, mentorship, documentation, and technical judgment.
• Build with AI agents across the engineering lifecycle, and help set patterns for using them safely on financial systems.
• Share operational ownership of critical financial systems through on-call, incident response, and continuous reliability improvements.

Qualifications

• Deep card payments experience at the message level: built or run integrations communicating with networks, acquirers, or processors (ISO 8583 or acquirer host formats). Acquiring/merchant-side experience is ideal; direct network connection experience is a strong plus; ISO 20022 is a plus.
• Experience with real card transaction edge cases, such as partial/incremental authorizations, reversals, tips, currency conversion, and interchange qualification.
• Strong hands-on software engineering experience building and operating highly reliable financial or payments systems at scale.
• Track record of leading technically complex projects from design through delivery and setting technical direction.
• Experience creating durable technical leverage (frameworks, standards, tooling, architecture, or practices).
• Broad understanding of card payment lifecycles (data security, tokenization, routing, authorization, capture, clearing, settlement, reconciliation, chargebacks).
• Understanding of card network rules (Visa, Mastercard, Amex, Discover, US debit networks) and payment processing architecture.
• Daily experience building with AI coding agents and sound judgment in evaluating their output.
• Willingness to participate in an on-call rotation for critical financial systems.

Application Guidelines

Candidates may submit up to 9 active applications within a 60-day period. Reapplications to the same role are accepted 90 days after a previous application has been reviewed.