Senior Backend Engineer - Payments & Billing (Hybrid)

Flex; United States; Hybrid; USD 172,000 - 215,000; Full time

Job summary

Flex, a NYC-headquartered fintech, is hiring a Senior Backend Engineer to design, build, and scale services behind Payment, Billing, Identity, and partner integrations. You will own APIs, drive production rollouts, and collaborate with product, design, and engineering to solve rental payments challenges in small iterations.

Join a fast-growing team with high ownership, where you’ll work on fault-tolerant systems, data pipelines, and scalable architectures using Java, Spring, and AWS.

Qualifications

• Minimum 6 years of software engineering experience.
• Minimum 4 years of Java experience.
• Experience working on globally distributed teams with ownership.
• Experience aligning with stakeholders on scope and delivery.
• Ability to thrive in a fast-paced environment.
• Experience building robust, fault-tolerant systems with multiple external dependencies.
• Experience designing, building, and maintaining data pipelines.
• Proficiency with Java frameworks and tools like Spring, Gradle, JUnit, JVM tuning.
• Experience with SOA, REST APIs, message queues, and scalable architectures.
• Experience with AWS (EKS, Aurora RDS, Elasticache, DynamoDB) and containers.

Responsibilities

• Design, build, and scale services and integrations behind Payment, Billing, Identity, and partner integrations.
• Lead scoping, design, and implementation for APIs you own.
• Drive production rollouts to completion with minimal oversight.
• Collaborate with product, design, and engineering peers to solve renters' problems in small iterations.

Skills

Java

REST APIs

SOA

AWS

CI/CD

Observability

Tools

Spring

Gradle

JUnit

Kubernetes

GitHub Actions

DataDog

Snowflake

CDK

Terraform

Job description

Flex, a NYC-headquartered fintech, is hiring a Senior Backend Engineer to design, build, and scale services behind Payment, Billing, Identity, and partner integrations. You will own APIs, drive production rollouts, and collaborate with product, design, and engineering to solve rental payments challenges in small iterations.

Join a fast-growing team with high ownership, where you’ll work on fault-tolerant systems, data pipelines, and scalable architectures using Java, Spring, and AWS.