Software Development Engineer Intern Jobs in Saint Louis, MO

ABOUT US:
LSEG (London Stock Exchange Group) is more than a diversified global financial markets infrastructure and data business. We are dedicated, open-access partners with a commitment to excellence in delivering the services our customers expect from us. With extensive experience, deep knowledge and worldwide presence across financial markets, we enable businesses and economies around the world to fund innovation, handle risk and create jobs. It's how we've contributed to supporting the financial stability and growth of communities and economies globally for more than 300 years.
Through a comprehensive suite of trusted financial market infrastructure services - and our open-access model - we provide the flexibility, stability and trust that enable our customers to pursue their ambitions with confidence and clarity.
LSEG is headquartered in the United Kingdom, with significant operations in 70 countries across EMEA, North America, Latin America and Asia Pacific. We employ 25,000 people globally, more than half located in Asia Pacific. LSEG's ticker symbol is LSEG.
Our People:
People are at the heart of what we do and drive the success of our business. Our culture of connecting, creating opportunity and delivering excellence shape how we think, how we do things and how we help our people fulfil their potential.
We embrace diversity and actively seek to attract individuals with unique backgrounds and perspectives. We break down barriers and encourage teamwork, enabling innovation and rapid development of solutions that make a difference. Our workplace generates an enriching and exciting experience for our people and customers alike. Our vision is to build an inclusive culture in which everyone feels encouraged to fulfil their potential.
We know that real personal growth cannot be achieved by simply climbing a career ladder - which is why we encourage and enable a wealth of avenues and interesting opportunities for everyone to broaden and deepen their skills and expertise.
As a global organisation spanning 70 countries and one rooted in a culture of growth, opportunity, diversity and innovation, LSEG is a place where everyone can grow, develop and fulfil your potential with significant careers.
Role Summary
As a Senior Software Engineer, you will contribute to the development of high-performance, real-time applications that process some of the world's most critical financial data. Our systems ingest information from global exchanges and deliver normalized, consistent market data to clients within milliseconds.
You will work primarily in C++ within a Linux-focused environment, collaborating with expert engineers while continuing to strengthen your skills in performance engineering, market data systems, and AI-enhanced development workflows.
What You will be Doing:

• Design, develop, and maintain clean, efficient, and well-structured applications.
• Use AI-assisted tools to support development tasks such as code generation, analysis, testing, and troubleshooting.
• Participate in code reviews to ensure code quality and consistency across the team.
• Develop and maintain robust unit tests and integration tests to support application quality and resilience.
• Collaborate with senior engineers and architects on design and implementation of features.
• Assist in integrating software into test and production environments by teaming with QA and Operations teams.
• Investigate and debug issues across development and test environments, including multi-threaded scenarios.
• Contribute to planning, refinement, and design discussions for new features and improvements.
• Work closely with teammates, Technical Architects, and Product Owners to implement solutions aligned to functional requirements.
• Communicate progress and technical details clearly within the team and to stakeholders.
• Responsibility of work you're doing while proactively seeking clarification or mentorship when needed.
• Expand your technical skillset through hands-on experience, training, and certifications.
• Establish understanding of system dependencies and broader business workflows over time.

What You will Bring:

• Bachelor's degree in Computer Science, Engineering, or equivalent experience.
• Strong programming experience with C++ and object-oriented development.
• Experience working within Linux development environments.
• Understanding of the full software development lifecycle.
• Strong problem-solving and analytical abilities.
• Familiarity with debugging tools and test-driven development.
• Ability to learn new technologies quickly and apply them optimally.
• Strong written and verbal communication skills.

Preferred Skills

• Experience with scripting languages such as Python, Bash, or PowerShell.
• Exposure to Agile development methodologies.
• Knowledge of automated testing frameworks.
• Understanding of multi-threaded programming concepts.
• Experience with containerized development and deployment (Docker, Kubernetes).
• Experience with Rust programming language or interest in learning Rust for development.
• Experience with or curiosity about:
  Real-time or low-latency systems
  Market data feeds or financial technology
• Familiarity with using AI tools in the software development lifecycle.

What You'll Gain

• Experience building high-throughput, low-latency systems at global scale.
• Access to mentorship from experts.
• An inclusive, collaborative engineering culture focused on learning and continuous improvement.
• Opportunities to deepen your expertise in C++, Linux, real-time systems, and AI-assisted engineering.

LSEG is a leading global financial markets infrastructure and data provider. Our purpose is driving financial stability, empowering economies and enabling customers to create sustainable growth.
Our purpose is the foundation on which our culture is built. Our values of Integrity, Partnership, Excellence and Change underpin our purpose and set the standard for everything we do, every day. They go to the heart of who we are and guide our decision making and everyday actions.
Working with us means that you will be part of a dynamic organization of 25,000 people across 65 countries. However, we will value your individuality and enable you to bring your true self to work so you can help enrich our diverse workforce.
We are proud to be an equal opportunities employer. This means that we do not discriminate on the basis of anyone's race, religion, color, national origin, gender, sexual orientation, gender identity, gender expression, age, marital status, veteran status, pregnancy or disability, or any other basis protected under applicable law. Conforming with applicable law, we can reasonably accommodate applicants' and employees' religious practices and beliefs, as well as mental health or physical disability needs.
You will be part of a collaborative and creative culture where we encourage new ideas. We are committed to sustainability across our global business and we are proud to partner with our customers to help them meet their sustainability objectives. Our charity, the LSEG Foundation provides charitable grants to community groups that help people access economic opportunities and build a secure future with financial independence. Colleagues can get involved through fundraising and volunteering.
LSEG offers a range of tailored benefits and support, including healthcare, retirement planning, paid volunteering days and wellbeing initiatives.
Please take a moment to read this privacy notice carefully, as it describes what personal information London Stock Exchange Group (LSEG) (we) may hold about you, what it's used for, and how it's obtained, your rights and how to contact us as a data subject.
If you are submitting as a Recruitment Agency Partner, it is essential and your responsibility to ensure that candidates applying to LSEG are aware of this privacy notice.
Join us and be part of a team that values innovation, quality, and continuous improvement. If you're ready to take your career to the next level and make a significant impact, we'd love to hear from you.
LSEG is a leading global financial markets infrastructure and data provider. Our purpose is driving financial stability, empowering economies and enabling customers to create sustainable growth.
Our purpose is the foundation on which our culture is built. Our values of Integrity, Partnership, Excellence and Change underpin our purpose and set the standard for everything we do, every day. They go to the heart of who we are and guide our decision making and everyday actions.
Working with us means that you will be part of a dynamic organisation of 25,000 people across 65 countries. However, we will value your individuality and enable you to bring your true self to work so you can help enrich our diverse workforce.
We are proud to be an equal opportunities employer. This means that we do not discriminate on the basis of anyone's race, religion, colour, national origin, gender, sexual orientation, gender identity, gender expression, age, marital status, veteran status, pregnancy or disability, or any other basis protected under applicable law. Conforming with applicable law, we can reasonably accommodate applicants' and employees' religious practices and beliefs, as well as mental health or physical disability needs.
You will be part of a collaborative and creative culture where we encourage new ideas. We are committed to sustainability across our global business and we are proud to partner with our customers to help them meet their sustainability objectives. Our charity, the LSEG Foundation provides charitable grants to community groups that help people access economic opportunities and build a secure future with financial independence. Colleagues can get involved through fundraising and volunteering.
LSEG offers a range of tailored benefits and support, including healthcare, retirement planning, paid volunteering days and wellbeing initiatives.
Please take a moment to read this privacy notice carefully, as it describes what personal information London Stock Exchange Group (LSEG) (we) may hold about you, what it's used for, and how it's obtained, your rights and how to contact us as a data subject.
If you are submitting as a Recruitment Agency Partner, it is essential and your responsibility to ensure that candidates applying to LSEG are aware of this privacy notice.
Career Stage:
Senior Associate
London Stock Exchange Group (LSEG) Information:
Join us and be part of a team that values innovation, quality, and continuous improvement. If you're ready to take your career to the next level and make a significant impact, we'd love to hear from you.
LSEG is a leading global financial markets infrastructure and data provider. Our purpose is driving financial stability, empowering economies and enabling customers to create sustainable growth.
Our purpose is the foundation on which our culture is built. Our values of Integrity, Partnership, Excellence and Change underpin our purpose and set the standard for everything we do, every day. They go to the heart of who we are and guide our decision making and everyday actions.
Working with us means that you will be part of a dynamic organisation of 25,000 people across 65 countries. However, we will value your individuality and enable you to bring your true self to work so you can help enrich our diverse workforce.
We are proud to be an equal opportunities employer. This means that we do not discriminate on the basis of anyone's race, religion, colour, national origin, gender, sexual orientation, gender identity, gender expression, age, marital status, veteran status, pregnancy or disability, or any other basis protected under applicable law. Conforming with applicable law, we can reasonably accommodate applicants' and employees' religious practices and beliefs, as well as mental health or physical disability needs.
You will be part of a collaborative and creative culture where we encourage new ideas. We are committed to sustainability across our global business and we are proud to partner with our customers to help them meet their sustainability objectives. Our charity, the LSEG Foundation provides charitable grants to community groups that help people access economic opportunities and build a secure future with financial independence. Colleagues can get involved through fundraising and volunteering.
LSEG offers a range of tailored benefits and support, including healthcare, retirement planning, paid volunteering days and wellbeing initiatives.
Please take a moment to read this privacy notice carefully, as it describes what personal information London Stock Exchange Group (LSEG) (we) may hold about you, what it's used for, and how it's obtained, your rights and how to contact us as a data subject.
If you are submitting as a Recruitment Agency Partner, it is essential and your responsibility to ensure that candidates applying to LSEG are aware of this privacy notice.