Senior Java API Developer

job summary:

Role Summary

We are seeking a Senior Java API Developer with robust experience in designing,

building, securing, and optimizing RESTful microservices on AWS. This role requires

deep expertise in Java, REST API design, application security, OAuth2, and AWS cloud

services, along with a solid understanding of design patterns, exception handling, and

testing frameworks. The ideal candidate will be responsible for delivering highly

performant, secure, and scalable APIs in a cloud-native environment.

Note: Hands on experience on AI tools is a plus.

Key Responsibilities

API Design & Development

Design, develop, and maintain RESTful APIs using Java and industry best

practices.

Define and implement REST API key features, including proper resource

modeling, HTTP methods, status codes, pagination, filtering, versioning, and

idempotency.

Apply object-oriented and application design patterns (e.g., Singleton,

Factory, Builder, Adapter, Strategy) to ensure maintainable and extensible

codebases.

Develop cloud-native APIs that integrate with AWS services and serverless

Components.

Performance & Scalability

Identify and implement REST API performance improvements, including:

o Efficient request/response payloads and serialization

o Caching strategies

o Connection pooling and resource optimization

o Asynchronous and non-blocking processing where applicable

Monitor and analyze application performance metrics and resolve bottlenecks.

Security

Implement application security best practices, including authentication,

authorization, encryption, and secure configuration management.

Design and implement OAuth2-based security using industry-standard flows

and grant types (Authorization Code, Client Credentials, Refresh Token, etc.).

Ensure APIs are protected against common vulnerabilities.

Exception Handling & Reliability

Design and implement robust exception handling strategies for APIs, ensuring

consistent and meaningful error responses.

Implement centralized logging, error tracking, and resiliency patterns (retry,

fallback, circuit breaker).

Testing & Quality

Write comprehensive unit, integration, and API tests using modern testing

frameworks.

Ensure high code quality through test coverage, code reviews, and adherence to

coding standards.

Support CI/CD pipelines with automated test execution.

Cloud & Infrastructure (AWS)

Design and deploy cloud resources using AWS CloudFormation.

Develop and integrate AWS Lambda functions for serverless use cases.

Configure and manage AWS IAM roles and policies following the principle of

least privilege.

Collaborate on cloud architecture decisions for scalability, security, and cost

optimization.

Collaboration & Leadership

Work closely with product owners, Technical Lead, architects, and DevOps teams

to deliver high-quality solutions.

Mentor junior developers and provide technical guidance and best practices.

Participate in design reviews, sprint planning, and production support activities.

Required Skills & Qualifications

Robust hands-on experience with Java and RESTful API development

Deep understanding of REST API design principles and key features

Solid knowledge of application design patterns

Proven experience with REST API performance optimization

robust background in application security and secure coding practices

Experience implementing exception handling and error management strategies

Hands-on experience with testing frameworks (unit, integration, API testing)

robust knowledge of OAuth2 and various grant types

Experience with AWS CloudFormation, AWS Lambda, and AWS IAM

Working knowledge of Python (scripting, automation, or Lambda development)

Experience working in Agile/Scrum environments

location: Malvern, Pennsylvania

job type: Contract

salary: $55 - 60 per hour

work hours: 8am to 5pm

education: Bachelors



responsibilities:

Key Responsibilities

API Design & Development

• Design, develop, and maintain RESTful APIs using Java and industry best

practices.

• Define and implement REST API key features, including proper resource

modeling, HTTP methods, status codes, pagination, filtering, versioning, and

idempotency.

• Apply object-oriented and application design patterns (e.g., Singleton,

Factory, Builder, Adapter, Strategy) to ensure maintainable and extensible

codebases.

• Develop cloud-native APIs that integrate with AWS services and serverless

Components.

Performance & Scalability

Identify and implement REST API performance improvements, including:

o Efficient request/response payloads and serialization

o Caching strategies

o Connection pooling and resource optimization

o Asynchronous and non-blocking processing where applicable

• Monitor and analyze application performance metrics and resolve bottlenecks.

Security

• Implement application security best practices, including authentication,

authorization, encryption, and secure configuration management.

• Design and implement OAuth2-based security using industry-standard flows

and grant types (Authorization Code, Client Credentials, Refresh Token, etc.).

• Ensure APIs are protected against common vulnerabilities.

Exception Handling & Reliability

• Design and implement robust exception handling strategies for APIs, ensuring

consistent and meaningful error responses.

• Implement centralized logging, error tracking, and resiliency patterns (retry,

fallback, circuit breaker).

Testing & Quality

• Write comprehensive unit, integration, and API tests using modern testing

frameworks.

• Ensure high code quality through test coverage, code reviews, and adherence to

coding standards.

• Support CI/CD pipelines with automated test execution.

Cloud & Infrastructure (AWS)

• Design and deploy cloud resources using AWS CloudFormation.
• Develop and integrate AWS Lambda functions for serverless use cases.
• Configure and manage AWS IAM roles and policies following the principle of

least privilege.

• Collaborate on cloud architecture decisions for scalability, security, and cost

optimization.

Collaboration & Leadership

• Work closely with product owners, Technical Lead, architects, and DevOps teams
• to deliver high-quality solutions.
• Mentor junior developers and provide technical guidance and best practices.
• Participate in design reviews, sprint planning, and production support activities.

qualifications:

Required Skills & Qualifications

Robust hands-on experience with Java and RESTful API development

Deep understanding of REST API design principles and key features

Solid knowledge of application design patterns

Proven experience with REST API performance optimization

robust background in application security and secure coding practices

Experience implementing exception handling and error management strategies

Hands-on experience with testing frameworks (unit, integration, API testing)

robust knowledge of OAuth2 and various grant types

Experience with AWS CloudFormation, AWS Lambda, and AWS IAM

Working knowledge of Python (scripting, automation, or Lambda development)

Experience working in Agile/Scrum environments

Preferred Qualifications

Experience with microservices and serverless architectures

Familiarity with API gateways and service-to-service authentication

Experience with monitoring, logging, and observability tools in AWS

Exposure to CI/CD pipelines and Infrastructure as Code (IaC) best practices

Equal Opportunity Employer: Race, Color, Religion, Sex, Sexual Orientation, Gender Identity, National Origin, Age, Genetic Information, Disability, Protected Veteran Status, or any other legally protected group status.

At Randstad Digital, we welcome people of all abilities and want to ensure that our hiring and interview process meets the needs of all applicants. If you require a reasonable accommodation to make your application or interview experience a great one, please contact

Pay offered to a successful candidate will be based on several factors including the candidate's education, work experience, work location, specific job duties, certifications, etc. In addition, Randstad Digital offers a comprehensive benefits package, including: medical, prescription, dental, vision, AD&D, and life insurance offerings, short-term disability, and a 401K plan (all benefits are based on eligibility).

This posting is open for thirty (30) days.


Any consideration of a background check would be an individualized assessment based on the applicant or employee's specific record and the duties and requirements of the specific job.