Senior Mainframe Security Engineer — Secure Modernization & TLS

Kelly Services; Plano (TX); On-site; USD 129,000 - 207,000; Full time

Benefits offered by this job

Medical, Dental, and Vision Insurance

Vacation Time

Stock Options

Job summary

Kelly Services in Plano, TX is seeking a Senior Mainframe Cybersecurity Software Engineer to modernize a long-established low-code platform. You will work across COBOL, C, and Java on z/OS, Linux, and Windows, ensuring secure software engineering and enterprise-level security integration.

The role combines hands-on development with security architecture, mentoring, and customer engagement, enabling influence over product direction and security thought leadership within a small, accomplished team.

Qualifications

• 12+ years of software engineering experience.
• Strong secure software development and secure coding practices.
• Expertise on z/OS and mainframe platforms.
• Proficient in COBOL, C, and Java.
• Experience modernizing legacy applications with security.
• Knowledge of authentication, authorization, cryptography, and secure application architecture.

Responsibilities

• Hands-on development across COBOL, C, Java.
• Security engineering focusing on TLS and authentication.
• Mentor and engage with customers, present security-focused topics.
• Lead architecture design for secure enterprise applications.
• Provide technical leadership within a small team.

Skills

Secure software development

COBOL development

C development

Java development

z/OS / Mainframe

Authentication & cryptography

TLS security

Hybrid mainframe & distributed systems

Troubleshooting & design

Education

Bachelor's degree

Job description

Kelly Services in Plano, TX is seeking a Senior Mainframe Cybersecurity Software Engineer to modernize a long-established low-code platform. You will work across COBOL, C, and Java on z/OS, Linux, and Windows, ensuring secure software engineering and enterprise-level security integration.

The role combines hands-on development with security architecture, mentoring, and customer engagement, enabling influence over product direction and security thought leadership within a small, accomplished team.