Senior Front End Developer

We are looking for a Senior SharePoint + React Developer to join our team supporting AT&T’s internal SharePoint platforms. This role involves building and maintaining custom front-end components using React.js within SharePoint Framework (SPFx), delivering high-performance and maintainable solutions that integrate with Microsoft 365 and external systems.

The ideal candidate has strong technical capabilities in React and SharePoint development, familiarity with enterprise environments, and excellent communication skills suited for client interaction.

You Will:

• Develop and maintain SPFx solutions using js within SharePoint Online

• Customize and extend SharePoint site functionality and front-end components

• Integrate SharePoint with external systems via REST APIs

• Optimize performance of components within strict platform constraints

• Collaborate with engineers, leads, and project stakeholders across geographies

• Support delivery within Agile/Kanban operating models

• Contribute to documentation and knowledge sharing

You Have:

• 5–8 years of professional front-end development experience

• Strong proficiency with React.js, modern JavaScript (ES6+), and TypeScript

• Deep understanding of SharePoint architecture, including lists, libraries, and permissions

• Experience with SharePoint Framework (SPFx)

• Familiarity with CI/CD principles and deployment constraints in enterprise environments

• Strong communication skills and team collaboration experience

• Proficient in English (written and verbal)

Nice to have:

• Basic knowledge of Azure Active Directory and Azure Functions

• General awareness of the Power Platform (Power Automate, Power Apps)

• Experience working in compliance-heavy environments

• Background in enterprise-level support or SW enhancement projects

What we offer:

• Maternity and parental leave extra days

• Competitive benefits packages

• Vacation, compassionate leave, sick days, and flex days

• Access to online services for families and new parents

• Diversity and Inclusion Board with 12 affinity groups

• Internal learning and development programs

• Enterprise-wide employee discounts

• And more…

At Critical Mass, we value our employees and offer competitive compensation and benefits packages. If you’re looking for a challenging and rewarding opportunity to make a significant impact on the lives of our employees, we encourage you to apply for this exciting position today!

The Talent Team at Critical Mass is focused on ensuring we provide the best training, onboarding, and employee experience possible! Our new hires & employees are the future of our organization, and we want to set you up for long-term success. In an effort to do so, we expect our team to work from an office a minimum of 3 days a week.

The ask stems from our want to:

Strengthen opportunity for continuous learning
Improve collaboration and team relationships.
Increase employee engagement

This work model balances the need for individual flexibility while maintaining the relentless customer focus we provide at CM. We understand that not everyone may feel comfortable with this expectation, so we ask that you please let us know immediately if there are any concerns so we can help navigate accordingly.

Critical Mass is an equal opportunity employer.

Critical Mass uses artificial intelligence in our recruitment process to enhance job postings, filter keywords during the review of prospective candidates, and, in some cases, transcribe interviews with our recruiters. Human review remains central to the process, and all hiring decisions are ultimately made by our team.

The Critical Mass Talent Acquisition team will only communicate from email addresses that use the URLs criticalmass.com, omc.com and us.greenhouse-mail.io. We will not use apps such as Facebook Messenger, WhatsApp, or Google Hangouts for communicating with you. We will never ask you to send us money, technology, or anything else to work for our company. If you believe you are the victim of a scam, please review your local government consumer protections guidance and reach out to them directly.

If U.S. based: https://www.consumer.ftc.gov/articles/job-scams#avoid
If Canada based: https://www.canada.ca/en/services/finance/consumer-affairs.html
If U.K. based: https://www.gov.uk/consumer-protection-rights
If Costa Rica based: https://www.consumo.go.cr/educacion_consumidor/consejos_practicos.aspx