The register
The register lists Reddit UK Ltd in London as a licensed sponsor on Global Business Mobility: Senior or Specialist Worker and Skilled Worker, 2 routes in all, and has done since at least 2026. Its rating on the register is Worker (A rating).
Companies House lists it as Reddit UK Limited, number 12434044, incorporated 2020: 6 years of filings behind the name. Registered office: 5 New Street Square, London, EC4A 3TW, EC4A 3TW. By its SIC codes the business is in it, software and media.
A licence says an organisation may sponsor; it does not say it is hiring today. The way to find out is the same as for any employer: the careers page, the job boards, and a direct approach with a UK-style CV that says early that sponsorship would be needed.