Since we opened our doors in 2009, the world of commerce has evolved immensely, and so has Square. After enabling anyone to take payments and never miss a sale, we saw sellers stymied by disparate, outmoded products and tools that wouldn't work together.

So we expanded into software and started building integrated, omnichannel solutions – to help sellers sell online, manage inventory, offer buy now, pay later functionality, book appointments, engage loyal buyers, and hire and pay staff. Across it all, we've embedded financial services tools at the point of sale, so merchants can access a business loan and manage their cash flow in one place. Afterpay furthers our goal to provide omnichannel tools that unlock meaningful value and growth, enabling sellers to capture the next generation shopper, increase order sizes, and compete at a larger scale.

Today, we are a partner to sellers of all sizes – large, enterprise-scale businesses with complex operations, sellers just starting, as well as merchants who began selling with Square and have grown larger over time. As our sellers grow, so do our solutions. There is a massive opportunity in front of us. We're building a significant, meaningful, and lasting business, and we are helping sellers worldwide do the same.

The Role

Foundation iOS builds, maintains, and enables platform-level capabilities, architectural foundations, and developer tools that keep Square's iOS apps performant, reliable, observable, and scalable. This includes our flagship product Point of Sale and all of Square's seller-facing iOS applications.

We're the backbone that enables Square's 150+ iOS engineers to build and ship features efficiently and reliably. Our mandate spans the core infrastructure that powers Square's mobile ecosystem: from state management and dependency injection to networking primitives, data persistence, testing frameworks, and the modular architecture that enables distributed development across multiple teams.

Why? Building reliable, performance mobile applications at Square's scale requires robust foundational systems. Foundation iOS ensures that product engineers have the architectural primitives, tools, and frameworks they need to deliver high-quality experiences to Square's sellers without reinventing the wheel.

Our core systems includes:

Workflow: Square's state management framework
Bazel: Our build system
Dependency injection system
Testing systems: Unit testing, UI automation, snapshot frameworks Data Persistence
Observability: Frameworks and dashboards to monitor our applications' performance & reliability

We work closely with peer teams like UI Systems, Release Engineering, Mobile Developer Experience, and all product engineering teams.

As a staff engineer on Foundation iOS, you'll work closely with Foundation leads and technical leads across Square to set technical direction, drive architectural decisions, and evangelize foundational improvements that benefit the entire iOS organization. You'll be expected to identify system issues that span team boundaries and drive cross-functional solutions to completion.

You Will

Build and evolve core architectural frameworks that power Square's iOS applications, including state management, dependency injection, networking primitives, data persistence layers, observability frameworks, and testing systems.
Drive technical excellence across Square's iOS codebase by identifying performance bottlenecks, reliability issues, and developer productivity pain points, then building solutions that scale across hundreds of engineers.
Lead cross-team initiatives such as iOS version upgrades, application architecture improvements, memory leak remediation, and migration from legacy systems to modern frameworks.
Partner with product engineering teams to embed foundational improvements, provide technical guidance, and ensure smooth adoption of new frameworks and tools.
Maintain critical infrastructure including our module structure and code generation tools.
Drive performance and reliability improvements by building automated testing systems, observability tools, and architectural changes that prevent regressions and improve app quality.
Mentor and enable other engineers through documentation, education, technical reviews, and fostering communities of practice around mobile development best practices.

You Have

12+ years iOS development experience, deep expertise in both legacy and modern iOS frameworks.
Strong systems thinking and experience building foundational frameworks, developer tools, or platform-level infrastructure at medium to large scale.
Experience with build systems and tooling, preferably Bazel, along with understanding of modular architecture, dependency injection, and state management (TCA, Redux, etc).
Performance and reliability expertise including memory management, crash analysis, and building systems for observability and monitoring.
Experience as a technical lead for complex, multi-quarter projects with significant organizational impact.
Strong communication skills for technical writing, architecture reviews, and presenting to both technical and non-technical audiences.
Experience with being independent, have a strong bias towards action, and be a self-starter. We use processes to help us, not to constrain us.

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.

While there is no specific deadline to apply for this role, U.S. roles are typically open for an average of 55 days before being filled by a successful candidate. Please refer to the date listed at the top of this job page for when this role was first posted.

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 this resource. If a location of interest is not listed, please speak with a recruiter for additional information.

Zone A:

$263,600—$395,400 USD

Zone B:

$263,600—$395,400 USD

Zone C:

$263,600—$395,400 USD

Zone D:

$263,600—$395,400 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 at privacy@block.xyz with 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. Square makes commerce and financial services accessible to sellers. Cash App is the easy way to spend, send, and store money. Afterpay is transforming the way customers manage their spending over time. TIDAL is a music platform that empowers artists to thrive as entrepreneurs. Bitkey is a simple self-custody wallet built for bitcoin. Proto is a suite of bitcoin mining products and services. Together, we’re helping build a financial system that is open to everyone.