INTERNSHIP DETAILS

Development Intern

CompanyCritical Mass
LocationLondon
Work ModeOn Site
PostedFebruary 19, 2026
Internship Information
Core Responsibilities
The intern will gain exposure to all aspects of the technology discipline, working with a tech lead and collaborating with other departments like creative and UX. Responsibilities include delivering solutions that balance technical and business requirements while maintaining high coding standards.
Internship Type
full time
Company Size
1847
Visa Sponsorship
No
Language
English
Working Hours
40 hours
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About The Company
We’re Critical Mass. We are 2,000 inspired humans across 14 offices, setting the right path—not just the next one—for our clients, their customers, and our own colleagues. We work with the best, Apple, Adobe, BMW, Nike, Diageo, Airbnb, BNY and many more, to power connected ecosystems that make brands stand out by driving performance with data, technology, AI, creative and media. We’re a global marketing agency founded in Canada, but digital is our home. If you know us, then you know we’re a special place that attracts big talent and tiny egos. We’re driven, uncompromising and we live our values. We’re Critical Mass, but our friends call us CM. Learn more at criticalmass.com.
About the Role

Critical Mass’ Internship opportunities are part of our Trailhead Program and provide a 12-week jump-start to your career. The program is designed to fast-track your growth through regular learning opportunities, mentorship, and hands-on client work - all while earning a competitive stipend. You’ll get a firsthand look at the exciting work we do at Critical Mass and experience what it’s like to be an integral part of our team. This internship gives you the chance to explore the digital agency world and client projects to see if it’s the right fit for you.

Our internship will run from May 26 – August 14.

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.

As a development intern, you will get to work with a tech lead to gain experience to all the different aspects of the technology discipline at Critical Mass. You will gain experience seeing how the technology team works with different departments like creative and UX to create top-notch user experiences. You will have a foundational knowledge of languages like HTML, CSS and Javascript and a passion to learn more. Most importantly, you are driven to hone your craft through a passion for technology.   

You Will: 

  • Gain exposure to all elements of the technology discipline at Critical Mass.  
  • Understand how technology fits into the Critical Mass agency offerings.  
  • Collaborate with other interns on a client project and our global intern project.  
  • Deliver solutions balancing technical and business requirements.   
  • Understand business and user requirements.  
  • Maintain high coding standards and practices to exercise quality control on all aspects of web development.  
  • Problem-solve in all areas of web development. 

You Have: 

  • Demonstrated development experience with hand-coding advanced HTML, CSS, HTML5, CSS3, and JavaScript through class or certificate program. 
  • Demonstrated development exposure to React or VUE.   
  • Package manager and automation tool experience (npm, gulp, grunt).   
  • Basic understanding of Responsive Web Design principles.  
  • Proficiency with Semantic HTML Markup.  
  • Aptitude to collaborate and work with cross discipline teams.  
  • Exposure in diagnosing and solving cross-browser and cross-platform issues. 
  • Currently in 2nd or 3rd year of a 4-year degree or 1st year of a 2-year specialization program 

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 

Key Skills
HtmlCssJavascriptReactVueNpmGulpGruntResponsive Web DesignSemantic Html MarkupCross-browser IssuesCross-platform Issues
Categories
SoftwareTechnologyCreative & MediaConsulting