Senior Backend Engineer - Payments & APIs (FinTech)

Flex (Financial Services); United States; Hybrid; USD 146,000 - 215,000; Full time

Benefits offered by this job

Relocation assistance

Hybrid work model

Job summary

Flex (Financial Services) is seeking a Senior Backend Engineer to design, build, and scale services behind Payment, Billing, Identity, and partner integrations. You will own APIs end-to-end, drive production rollouts, and collaborate closely with product, design, and engineering teams to deliver reliable, modular services in frequent iterations.

You will work on globally distributed teams, applying Java, Spring, and data-pipeline skills to create robust, fault-tolerant systems that support

Qualifications

• Minimum of 6 years experience in software engineering.
• Minimum of 4 years experience with Java and Spring framework.
• Experience designing, building, and maintaining data pipelines.
• Ability to work on a globally distributed team with ownership.
• Experience with REST APIs, message queues, and scalable architectures.
• Experience with AWS services and containerization.
• Proficiency with CI/CD, observability, and alerting tools.

Responsibilities

• Design, build, and scale services behind Payment, Billing, Identity, and partner integrations.
• Own APIs end-to-end, drive production rollouts with minimal oversight.
• Collaborate with product, design, and engineering peers in small, frequent iterations.
• Mentor engineers and elevate team standards through best practices.

Skills

Software engineering

Java

Distributed systems

Data pipelines

AWS

REST APIs

CI/CD

Observability

Tools

Spring

Gradle

JUnit

JVM tuning

AWS (EKS, Aurora RDS, Elasticache, DynamoDB)

Containerization

DataDog

Snowflake

CDK / Terraform

Job description

Flex (Financial Services) is seeking a Senior Backend Engineer to design, build, and scale services behind Payment, Billing, Identity, and partner integrations. You will own APIs end-to-end, drive production rollouts, and collaborate closely with product, design, and engineering teams to deliver reliable, modular services in frequent iterations.

You will work on globally distributed teams, applying Java, Spring, and data-pipeline skills to create robust, fault-tolerant systems that support