Freelance Senior Copywriter

As a Freelance Senior Copywriter, you are a seasoned writer who loves to collaborate with creatives and strategists to bring a digital voice to life. Grasping communication challenges and devising solutions that are both elegant and on-brand is what you do. You have a copy editor’s eye for detail and a managing editor’s ability to juggle multiple campaigns at once.

Copy is your comfort-zone, but you’ve got a well-rounded knowledge of the broader industry—social media, usability, online marketing, and traditional advertising. You’re also a dynamic leader who can run point on copy development for complex campaigns, and be an inspiring mentor to junior copy staff.

You Will:

• Write clear, concise, and engaging copy for emails, landing pages, paid/unpaid ads and more.


• Interact with stakeholders to understand business objectives and audience demographics


• Partner with designers, marketers, and product teams to ensure cohesive messaging.


• Uphold the client’s brand voice across all written content.


• Stay up-to-date with industry trends, audience behaviors, and competitor activities.


• Use research and data-driven insights to inform content strategy.

You Have:

• 5+ years’ experience as a copywriter or editor in an agency, publishing, or journalism environment—including experience with interactive media and direct marketing.


• Ability to internalize and consistently adhere to internal brand guidelines


• Exceptional writing and editing skills, including the ability to quickly review, edit, and QA a wide variety of comms.


• Proven aptitude for quick, creative thinking with acute attention to detail within demanding deadlines.


• A strong understanding of marketing (especially direct marketing) and advertising principles.


• The ability to work on multiple projects simultaneously and effectively juggle diverse writing demands.

Critical Mass is an equal opportunity employer. 

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