Principal Software Engineer, Full Stack

We are seeking an experienced Principal Software Engineer to lead complex projects, and mentor teams in building scalable and reliable full-stack solutions. The person in this role will play a pivotal role in shaping the technical direction of our platform and ensuring its continued success.

CMT is looking for a Principal Software Engineer I, Full Stack to help us change the world. CMT has helped protect over 65 million drivers and prevent over 126,000 crashes worldwide. We build AI to solve some of the most difficult challenges in mobility — understanding and reducing risk, detecting crashes, and getting people life-saving help. The problems are hard. The impact is real. No matter your role, your work will matter at CMT.

Responsibilities:

Lead the development of critical features and components, ensuring high quality and timely delivery

Provide technical guidance and mentorship to engineering teams, fostering a culture of excellence

Identify and resolve complex technical challenges, proactively mitigating risks.

Lead cross functional technical projects

Evaluate and recommend new technologies and approaches to improve system performance and efficiency

Design and implement robust, scalable, and maintainable architectures for complex systems

Collaborate with product and engineering leaders to define technical roadmaps and strategies

Anticipate future technical needs and ensure the platform is prepared for growth

Contribute to the development of best practices and standards for software development

Ensure the reliability and performance of production systems, providing on-call support as needed

Drive continuous improvement initiatives to enhance operational efficiency

Troubleshoot and resolve complex production issues, minimizing downtime

Follow company defined development and operational standards and processes

Mentor and guide senior and junior engineers, fostering their technical growth

Lead code and design reviews, ensuring adherence to best practices

Collaborate effectively with cross-functional teams, including product, QA, and operations

Participate heavily in the hiring process, and improve the hiring process

Complete any additional tasks as they arise

Qualifications:

Bachelor’s degree or equivalent years of experience and/or certification in a technical field

7+ years of relevant professional experience

Deep expertise in web technologies (HTML, CSS, JavaScript, TypeScript) and modern web frameworks (e.g., React, Django)

Extensive experience designing or developing Restful APIs or web services

Strong proficiency in a backend development language (e.g. Python, Java)

Expertise in cloud platforms (e.g., AWS), including services like EC2, S3, Lambda, SNS, SQS, RDS (Postgres), and NoSQL databases.

Proven ability to design and implement scalable and resilient systems.

Strong understanding of software development best practices, including testing, CI/CD, and DevOps

Understanding of Agile development methodologies (specifically Scrum)

Excellent communication and collaboration skills

Customer obsessed, demonstrates initiative, has a learning mindset, takes ownership

Demonstrated ability to drive technical initiatives and influence architectural decisions.

Strong experience with system design

Compensation and Benefits:

Fair and competitive salary based on skills and experience, and annual performance bonus

Equity may be awarded in the form of Restricted Stock Units (RSUs)

Medical, Dental, Vision and Life Insurance, matching 401k, short-term long-term disability and parental leave

Unlimited Paid Time Off including vacation, sick days public holidays

Flexible scheduling and work from home policy depending on role and responsibilities

Base Salary Range

The base salary range for this position is: $167,200 to $209,000. This range is specifically for Cambridge, MA

Additional Perks:

Work on a mission with real impact: crashes prevented, injuries avoided, lives protected around the world

Join an industry leader — 65 million drivers protected, powering 140+ programs across 25 countries

Recognized innovator in mobility AI, earning top honors including the TIME Industry Leader in AI, a Gold Edison Award, and the Artificial Intelligence Excellence Award for AI for Social Good. CMT is also Great Place to Work Certified

Be part of the team inventing the future of mobility and road safety

Move fast, own outcomes, do work that matters

High ownership, small teams, and direct access to leadership — no layers between your work and its impact

Unlimited PTO, flexible scheduling, competitive salary, annual performance bonus, RSUs, and full benefits including medical, dental, vision, and 401k match

Summer Fridays provide team members with half days to recharge

Join one of our employee resource groups: Black, AAPI, LGBTQIA+, Women, Book Club, and Health Wellness

Comprehensive wellness, education, and employee assistance programs

Commitment to Diversity and Inclusion:

At CMT, we be…