Principal iOS Engineer, Mobile Performance & Reliability

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
The Mobile Performance & Reliability team is responsible for guiding Square's mobile engineering organization to deliver highly performant and reliable experiences to our sellers, while also improving Square's ability to observe apps in the wild and respond to issues proactively.
As a Principal iOS Software Engineer on the Mobile Performance & Reliability team, you would join the foundational team responsible for driving mobile application quality across all of Square. You would tackle challenges across our entire suite of apps and in some cases the entire iOS platform. You would work closely with the authors and maintainers of some of the most used open-source libraries in the iOS space.
You Will

• Identify, scope, and lead complex, strategic projects with wide impact across the company
• Lead engineering designs with company-wide impact, ensuring these designs succeed in the long term
• Design highly available and resilient systems which can operate no matter the network or device conditions
• Collaborate with multiple stakeholders across the company including product, design, legal, support, and other engineering teams
• Provide mentorship, expertise and design reviews for engineering teams across Square.
• Develop a strategic vision that influences the company's overall engineering direction, decisions, and the prioritization of the projects on our roadmap

You Have

• 15 or more years of professional software development experience
• Deep understanding of the iOS platform, Swift, and Objective-C
• Ability to break down complex projects into components or milestones that can easily be picked up by other engineers
• Skill to investigate and identify the root cause of an issue in an unfamiliar codebaseMotivation to influence our engineering organization to level-up the reliability and performance of the mobile apps we ship.
• Demonstrated collaboration with co-workers on cross-functional teams
• A strong sense of ownership
• Desire to understand and alleviate developer pain points
• Desire to facilitate adoption through high-quality documentation, tutorials, samples, and pairing
• Experience building frameworks related to performance, reliability, observability, and analytics
• Experience building engineering tools or profilers related to improve performance and reliability
• Experience as a maintainer or contributor to Open Source projects
• Experience optimizing the performance of iOS applications
• Experience working in a large engineering organization (hundreds of mobile engineers)

Technologies We Use and Teach

• Swift, Objective-C, Xcode, and Instruments
• UIKit, SwiftUI, CoreAnimation, CoreData, MetricKit
• Analytics and observability frameworks
• Unit tests, snapshot tests, integration tests
• Protocol buffers
• Bazel for our build environment

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 a proud equal opportunity employer. We work hard to evaluate all employees and job applicants consistently, without regard to race, color, religion, gender, national origin, age, disability, veteran status, pregnancy, gender expression or identity, sexual orientation, citizenship, or any other legally protected class.
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.
Block will consider qualified applicants with arrest or conviction records for employment in accordance with state and local laws and "fair chance" ordinances. Because the material duties of this role involve direct or indirect access to sensitive personal or financial data, a criminal background check is required following a contingent offer of employment.
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:
$290,000 - $435,000 USD
Zone B:
$290,000 - $435,000 USD
Zone C:
$290,000 - $435,000 USD
Zone D:
$290,000 - $435,000 USD
Block, Inc. (NYSE: SQ) is a global technology company with a focus on financial services. Made up of Square, Cash App, Spiral, TIDAL, and TBD, we build tools to help more people access the economy. Square helps sellers run and grow their businesses with its integrated ecosystem of commerce solutions, business software, and banking services. With Cash App, anyone can easily send, spend, or invest their money in stocks or Bitcoin. Spiral (formerly Square Crypto) builds and funds free, open-source Bitcoin projects. Artists use TIDAL to help them succeed as entrepreneurs and connect more deeply with fans. TBD is building an open developer platform to make it easier to access Bitcoin and other blockchain technologies without having to go through an institution.