Staff Software Engineer, Financial Platform - Issuing at Block · LumiJobs

Responsibilities

At Block, we strive to build the best financial products in the world. The Financial Platform Issuing team owns the card issuing platform that serves every Block brand — powering Cash App Card, the fourth-largest debit card program in the US, alongside Square Card and the new card programs Block launches next.
We run the full lifecycle of a card: issuance, fulfillment, and activation; real-time transaction authorization and processing across card networks; digital wallet provisioning; 3-D Secure authentication; clearing and settlement; and disputes. When a customer taps their card at a register, our systems decide the outcome in milliseconds, around the clock, in partnership with card networks and bank partners.
As a Staff Software Engineer on the Issuing server engineering team, you will bring deep card-network expertise to some of the most complex technical work on our roadmap. You will work alongside technical leads and cross functional teams, going deep where our platform meets the networks: specifications, protocols, certification, mandates, conformance, and production behavior.
This is a hands-on role. You will build systems and tooling, debug at the message level, and turn your network expertise into durable capabilities that other engineers can use. You will also work directly with the networks themselves — not only understanding what they require, but knowing where and how to influence outcomes for Block.
Be a deep technical expert on global card networks, helping Issuing teams interpret network specifications, message flows, certification requirements, mandates, and production behavior — and working directly with the networks to influence requirements, resolve ambiguity, and secure outcomes that matter for Block.
Lead complex, ambiguous engineering problems at the network boundary that span multiple teams, systems, or domains.
Partner with technical leads, program DRIs, and senior stakeholders to shape solutions where card-network requirements intersect with Block's issuing platform.
Stay deeply hands-on: write production code, build certification and conformance tooling, analyze network messages, review designs and code, and debug issues down to the protocol and field level.
Drive network certification and mandatory release cycles end to end, and translate network requirements into clear, pragmatic engineering decisions.
Establish shared frameworks, standards, tooling, and practices that make network expertise durable and enable teams to operate independently.
Raise the technical capability of engineers around you through design guidance, code reviews, mentorship, documentation, and clear technical judgment.
Apply AI-powered tools throughout the engineering lifecycle to improve velocity and quality, and help establish effective patterns for broader team use.

Qualification

DeepPersonally builtWe believe in being fair

Required

Deep, current expertise with at least one major card network, ideally Visa, including direct connectivity, ISO 8583, authorization and clearing flows, stand-in processing, specifications, certification, and mandate cycles.
Personally built, certified, or operated a live direct network connection — not only integrated through a processor.
Experience working directly with card networks to land concrete outcomes, such as rulings, exceptions, extensions, configuration changes, defect fixes, or certification outcomes.
Strong hands-on software engineering experience building and operating highly reliable financial or payments systems at scale.
A track record of leading technically complex, ambiguous work across team boundaries and influencing technical direction beyond your immediate area of ownership.
Experience creating durable technical leverage — frameworks, standards, tooling, architecture, or practices that other engineers and teams adopt.
Broad understanding of the card lifecycle, with depth in areas such as issuance and fulfillment, provisioning and activation, authorization, ledgering, clearing and settlement, reconciliation, disputes, or fraud.
Working knowledge of Mastercard and American Express, alongside deep expertise in at least one major network.
Fluency with AI-assisted engineering workflows and sound judgment in evaluating and applying AI-generated output.
Willingness to participate in an on-call rotation for critical financial systems.
We’re working to build a more inclusive economy where our customers have equal access to opportunity, and we strive to live by these same values in building our workplace. Block is an equal opportunity employer evaluating all employees and job applicants without regard to identity or any legally protected class. We will consider qualified applicants with arrest or conviction records for employment in accordance with state and local laws and “fair chance” ordinances.
We believe in being fair, and are committed to an inclusive interview experience, including providing reasonable accommodations to disabled applicants throughout the recruitment process. We encourage applicants to share any needed accommodations with their recruiter, who will treat these requests as confidentially as possible. Want to learn more about what we’re doing to build a workplace that is fair and square? Check out our I+D page.

Staff Software Engineer, Financial Platform - Issuing

Responsibilities

Qualification

Required

Benefits

Company

Block

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