Senior SDET Java REST API and Performance Testing

3Core Systems, Inc; Chicago (IL); On-site; USD 96,000 - 138,000; Part time

Job summary

3Core Systems, Inc. seeks a Senior SDET specializing in Java REST API and performance testing to join our Chicago team.

The role is onsite in Chicago, IL, with a 13-month contract and responsibilities spanning test automation development, framework design, and collaboration with developers and product teams. Ideal candidates have 3–5 years in REST API testing, 8+ years in test automation, and strong experience with JMeter, Cucumber, and Java.

Qualifications

• Strong experience with API testing and automation frameworks.
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Responsibilities

• Develop test automation code for API and performance testing.
• Plan design and maintain API test automation framework for CI/CD.
• Mentor test engineers and collaborate with developers and business users.
• Coordinate with product owner to resolve issues and understand functionality.
• Create automated functional scripts using Java, Karate, JMeter.

Skills

API

Automation Testing

Cucumber

Java

JMeter

REST

Education

Bachelor’s Degree

Tools

JBehave

Job description

Senior SDET Java REST API and Performance Testing

Chicago, United States | Posted on 10/29/2026

Role: Senior SDET Java REST API and Performance Testing (509924)

Location: Chicago, IL - Onsite 3-5 days/week

Duration: 13 MonthContract

Must Have Skills/Attributes

• API, Automation Testing, Cucumber, Java, JMeter, REST

Experience Desired

• Java, Cucumber, JBehave, BDD testing frameworks (3-5 Years)
• Experience testing Webservices/REST APIs (3-5 Years)
• Experience testing fullstack and integration testing with 3rd parties (8 Years)

Required Minimum Education

• Bachelor’s Degree

Job Description

RequiredSkills for the Senior SDET :

• Strong design and development skills in two or more of the following technologies and tools: Java (3-5 years) Cucumber (3-5 years), JBehave or other BDD testing frameworks
• At least 8 years of test automation framework design
• Strong experience in testing Webservices (REST APIs) (3+5 years)
• Proven experience developing test scripts, test cases, and testdata
• The ability to write queries in SQL or other relational databases
• 3+ years of experience in developing scenario based performance testing using JMeter
• Experience testing full stack and integration testing with 3rd parties
• End-to-end system integration testing experience for software platforms
• Ability to adapt quickly to a complex environment
• Pro‑active, flexible and creative
• Very strong communication skills and the ability to collaborate with developers and business users

Preferred Skills

• Hands on experience with Python
• Development experience in AWS Cloud technology
• Experience in TDD, continuous integration, code review practice is strongly desired
• Experience with Apigee or other API gateways is a plus
• Experience with DevOps concepts and tools (e.g., CI/CD, Jenkins, Git)
• At least 2 years working on an Agile team with a solid understanding of Agile/Lean practices.
• Understanding of a micro service Architecture
• Experience load and performance testing
• Extend testing automation framework using JAVA/JAVA Script
• Take ownership in understanding business requirements/ACs and develop test strategy/test plan
• Develop automation test cases using existing automation framework

Responsibilities

• Develop test automation code for Continuous Integration (CI), Continuous Delivery (CD), of systems, infrastructure, and test framework
• Plan, design, develop, and maintain API test automation framework that facilitates automation scripting, execution, and analysis of results
• Provide technical leadership and mentoring for test engineers on multiple applications/projects onshore and offshore; train and mentor project team members to create, execute, analyze, and maintain automated regression suites
• Coordinate with product owner to resolve open issues/enhancements/upgrades and understand the use of a specific functionality as needed
• Develop automated functional scripts using tools such as Java, Karate, JMeter
• Perform exploratory and manual testing of the product suite as appropriate
• Provide expertise in testing methodologies, best practices, and standards