You install Postman, open it, and hit a sign-in screen. Somewhere below the buttons is a smaller option: continue without an account, into what Postman calls the lightweight API client. If you're here, you probably want to know how far that path actually goes. Maybe your company restricts cloud tools, maybe you work in an air-gapped environment, or maybe you simply don't think sending requests to localhost should require an account.
Here's exactly what works without signing in, what doesn't, and what happens to your data if you sign in later, all verified against Postman's own documentation. Plus what to use when "mostly local" isn't enough.
The short answer
Without an account, Postman's lightweight API client is a request sender: you can make calls, read responses, and keep a local history. What you can't do is organize anything: no collections, no environments, no saved workflow. It's a scratchpad in the original sense: useful for one-offs, not a place to build.
Per Postman's documentation (checked August 2026):
