Staff Software Engineer, Agentic Integrations

Flex is a growth-stage, NYC headquartered FinTech company that is creating the best rent payment experience. It’s hard to believe that it’s 2025 and paying rent on time is expensive, inflexible, and difficult. We’re here to change that! Flex enables our users to pay rent throughout the month on a schedule that better fits their finances and budget. Our mission is to empower as many renters as possible with flexibility over their most significant recurring expense. After deliberately keeping a stealth profile as we built up unprecedented investor support and an enthusiastic user base, we are looking for motivated individuals to help us keep our mission growing. Will you be a part of the team?

About The Job

Flex is looking for a Staff Software Engineer to join our Partner Engineering organization and help build out our next-generation Agentic payments platform.

You will help shape the technical roadmap for the team, working across our APIs, SDKs, and Web experiences to power our Agentic platform & user experiences. You will work with teams across the organization including Engineering, Product, Design, Infrastructure, Sales, Partner and Customer Success to deliver products that wow our customers and drive business goals. We expect you to be hands-on and execute work as an individual, and build products that allow for flexibility as we evolve our product offerings.

Minimum Qualifications

• Minimum of 6 years experience in software engineering

• Experience leading the delivery of multiple highly impactful products end to end, on time with a high quality bar

• Experience working with technical and non-technical stakeholders, successfully aligning and setting expectations on scope and delivery

• Ability to drive yourself and your team to bring quality and consistency to their code and architecture, without compromising velocity

• Ability to grow in a fast-paced and dynamic environment that will challenge you to always bring your best

• Ability to work on a globally-distributed team with a high degree of ownership

• Excellent written and verbal communicator, with experience in cross-functional collaboration.

Preferred Qualifications

• Experience using LLMs & Agentic workflows to power consumer experiences

• Skilled at elevating team standards through best practices, and mentoring junior engineers.

• Experience building out pipelines that use LLMs to generate code from prompts

• Experience fine tuning LLMs to improve outcomes in an AI powered product

• Experience coupling LLM powered workflows with traditional programing processes to improve product outcomes

• Deep knowledge of networking protocols, request routing, WebSockets, and browser fingerprinting techniques.

• Experience with asynchronous programming & scalable architectures (Python asyncio, Twisted, Golang, Node.js).

• Proficient in CI/CD systems (preferably GitHub Actions), git, and automation

The salary compensation range for this role will be commensurate with the candidate's experience and Flex's internal leveling guidelines and benchmarks.

• For working locations in NY/NJ/CA, the base salary pay range will be $221,000-$262,000

• For all other states, the base salary pay range will be $199,000-$236,000

Life at Flex:

We understand that it takes a diverse team of highly intelligent, curious, determined, empathetic, and self aware people to grow a successful company. Our HQ is located in New York City, but we have employees located throughout the US, Australia, Canada and South America. We are growing quickly, but deliberately, with a focus on building an inclusive culture. Our dynamic team has incredible perspectives to share, just as we know you do, and we take great pride in being an equal opportunity workplace.

We offer many employee benefits & perks. For full-time U.S based positions we offer:

• Competitive medical, dental, and vision available from Day 1

• Company equity

• 401(k) plan with company match (our company match kicks off at the beginning of 2026)

• Unlimited paid time off + 13 company paid holidays

• Parental leave

• Flex Cares Program

• Free Flex subscription

For full time non-US employees, we offer

• Competitive compensation + company equity

• Unlimited PTO