An invitation to interview is a message a client sends from a job post to a specific freelancer or agency on Upwork, asking them to submit a proposal, which they can accept without spending Connects.
Clients find talent through Upwork's search, through its Talent Scout and sourcing services, or from a shortlist of people they have worked with, and invite them to a job. The invitation lands in the freelancer's inbox with the job post attached and two buttons: accept, which opens the proposal form at no Connects cost, and decline, with a reason. Upwork's Help Center encourages a quick answer either way, since an invitation left unanswered still counts against the client's view of the profile, and Upwork shows clients how responsive a freelancer has been.
The word interview is loose. Accepting an invitation submits a proposal and opens a message room; it is not a scheduled call unless the client arranges one. The proposal sent in reply competes with the others the client receives, so an invitation improves the odds without deciding them.
Invitations are where badges earn their keep. Upwork's search ranks Top Rated and Top Rated Plus profiles higher, Enterprise clients are shown vetted talent first, and the availability badge exists to attract invitations. Declining does not affect the Job Success Score; only contracts do. For agencies, invitations go to the member whose profile the client found, and the agency's owner or business manager can answer on their behalf.
How Upwork Insights uses it
This term describes Upwork's own rules or product rather than a figure the index measures; the pages that do carry live figures are the stats and rate pages.