Three hours into debugging a web automation script, you discover the problem: the session expired mid-workflow. But figuring that out required adding logging, rerunning the script, and parsing browser DevTools output. What you needed was simpler—a way to just look at the cookies.

Development teams install the Cookies.txt browser extension for exactly this moment. Click the icon, export cookies, open the text file. Right there in plain text: which authentication tokens exist, when they expire, which domains they cover. The extension exports in Netscape format—the format that wget, curl, and yt-dlp expect. No parsing, no conversion.

At TinyFish, we run enterprise web agent infrastructure handling authentication across thousands of sites. Our developers keep Cookies.txt installed because when a workflow fails at 3 AM, they need to see cookie expiration timestamps immediately—not write inspection code. But our production systems use programmatic APIs because manual export doesn't scale to 10,000 concurrent sessions. The extension solves a different problem: making authentication state visible during development.

Export and Feed

The immediacy is what matters. A developer testing regional authentication variations logs into a Japanese e-commerce site through Chrome, clicks the Cookies.txt icon, exports. The file looks like this:

Domain, path, expiration timestamp, cookie name, value—all visible. Now feed it to curl: curl --cookie cookies.txt https://example.com/api/data. The authenticated session transfers from browser to command line without writing cookie serialization code.

Users report straightforward workflows:

They're moving authentication state from browser to command-line tool without writing integration code.

Manual Beats Programmatic

You're debugging authentication failures and need to see what cookies actually exist—not just whether authentication works, but what tokens are present and when they expire. You need to test a curl command with authenticated session state without implementing programmatic login. You're reproducing a bug that requires specific authentication state and manual login is faster than scripting it.

A QA engineer can manually log into a staging environment with complex authentication, export the session, share the cookie file with developers who need to reproduce the authenticated state without staging credentials. The file becomes portable session state. No API documentation, no serialization libraries.

The Get cookies.txt LOCALLY variant emphasizes that it "never sends information outside" and its "source code is open-source, very small, and not obfuscated". The security model is simple: whoever has the file has your session.

What It Doesn't Handle

Cookies.txt doesn't handle production automation challenges. It won't manage authentication across thousands of concurrent sessions. It won't implement token refresh logic when sessions expire. It won't integrate with CI/CD pipelines that need automated authentication without human intervention.

Teams pick it over Chrome DevTools' cookie inspector when they need the Netscape format specifically—because their command-line tools expect it. They pick it over programmatic cookie APIs when iteration speed matters more than automation—when seeing what's happening is more valuable than scripting it.

At TinyFish, when authentication breaks across our agent fleet, we often need to understand exactly what state existed at failure time. The extension makes this inspection trivial during development. Production workflows that run without human oversight need programmatic session management instead.