55 Senior Software Development Engineer Security jobs in San Francisco United States

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 Go-to-Market Engineering team builds the systems, automations, and AI-powered experiences that help our sales teams spend less time on manual work and more time serving customers. As a Staff Software Engineer, you will be the technical owner of our go-to-market technology stack, setting its architecture and long-term direction while leading engineers through complex, high-impact sales problems. You will partner with Sales, Sales Strategy & Operations, Product, Data, and Engineering leaders to deliver reliable, scalable solutions that improve sales productivity and business performance.

You Will

• Own the technical strategy, architecture, and long-term evolution of our go-to-market technology stack.
• Design, build, and operate production-grade AI agents and automated workflows that reduce manual sales work, improve decision-making, and give time back to sales teams.
• Lead technical execution across initiatives of varying sizes by setting direction, breaking down complex problems, reviewing designs, and helping engineers deliver high-quality solutions.
• Remain hands-on throughout the software lifecycle, from prototyping and architecture through implementation, testing, deployment, and production operations.
• Partner with Sales and Sales Strategy & Operations to understand workflows, identify high-value opportunities, and translate business problems into scalable technical solutions.
• Establish the patterns, evaluation methods, and guardrails needed to build AI systems that are reliable, observable, secure, and safe to use with sensitive business data.
• Define success measures and use data, evaluations, and user feedback to improve the accuracy, adoption, and business impact of new capabilities.
• Make thoughtful build-versus-buy decisions and guide integrations across internal platforms, customer relationship management systems, data services, and third-party tools.
• Build alignment with senior technical and business partners, communicate complex tradeoffs clearly, and raise engineering standards through mentorship and design reviews.

You Have

• A minimum of 12 years of related experience with a Bachelor’s degree; or 8 years and a Master’s degree; or a PhD with 5 years experience; or equivalent experience.
• Experience setting technical direction and delivering complex, business-critical systems across multiple teams or functional areas.
• Experience designing, building, and operating production software that uses large language models, AI agents, tool calling, retrieval, workflow orchestration, or related technologies.
• A track record of moving AI capabilities from prototype to production, including evaluation, observability, security, reliability, and human oversight.
• An AI-native approach to engineering, using AI tools throughout development while applying sound judgment about when to use models, deterministic software, or human review.
• Strong software engineering and system-design skills, with the ability to work hands-on across application, service, integration, and data layers.
• Experience leading technical execution through influence, mentorship, architecture, and direct contribution, without relying on formal reporting authority.
• The judgment to navigate ambiguous problems, evaluate technical and business tradeoffs, and influence senior engineering and business partners.
• Familiarity with sales processes or go-to-market systems—such as lead management, opportunity management, forecasting, account planning, or customer relationship management platforms—is helpful but not required.

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.

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.

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

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.

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 here 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.

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.