Senior Staff Software Engineer - FinTech Payments & APIs

Flex; United States; Hybrid; USD 204,000 - 300,000; Full time

Benefits offered by this job

Medical, dental, and vision

Company equity

401(k) with company match

Unlimited PTO + 13 holidays

Parental leave

Free Flex subscription

Job summary

Flex, a NYC-based FinTech, seeks a Senior Staff Software Engineer to own the technical roadmap across APIs, SDKs, and web experiences. You’ll collaborate with Engineering, Product, Design, Infrastructure, Sales, Partner, and Customer Success to align strategy with business goals while delivering hands-on contributions.

You’ll lead distributed teams, drive end-to-end product delivery, and shape integrations with external partners and payment rails, all within a fast-paced environment that rewards

Qualifications

• Bachelor or above degree in Computer Science or a related field.
• 10+ years of software engineering experience with at least 3 years in hands-on technical leadership.
• Experience working with globally distributed teams and high ownership.
• Led end-to-end delivery of multiple high-impact products on time and with quality.
• Experience aligning scope and delivery with technical and non-technical stakeholders.
• Drive quality and architectural excellence without sacrificing velocity.
• Thrives in a fast-paced dynamic environment.
• FinTech experience and familiarity with major payment rails.
• Experience building integrations with external partners and managing stakeholder relationships.
• Experience working on AWS cloud-based applications.

Responsibilities

• Oversee the technical roadmap across APIs, SDKs, and web experiences.
• Collaborate with Engineering, Product, Design, Infrastructure, Sales, Partner and Customer Success.
• Be hands-on and deliver individual contributions while guiding the team.
• Build products that allow for flexibility as we evolve offerings.
• Lead Partner Integrations to standardize APIs and processes.

Skills

Software engineering

Technical leadership

Distributed team collaboration

Stakeholder management

Ownership culture

Cloud experience

Education

Bachelor’s degree in Computer Science or related field

Tools

AWS

APIs

SDKs

Job description

Flex, a NYC-based FinTech, seeks a Senior Staff Software Engineer to own the technical roadmap across APIs, SDKs, and web experiences. You’ll collaborate with Engineering, Product, Design, Infrastructure, Sales, Partner, and Customer Success to align strategy with business goals while delivering hands-on contributions.

You’ll lead distributed teams, drive end-to-end product delivery, and shape integrations with external partners and payment rails, all within a fast-paced environment that rewards