Is cookies.txt lossless if I only have name and value?

Name, value, domain, path, secure, host-only, expiry and HttpOnly (via prefix) survive. Everything else does not. Most “simple” cookies look fine; auth cookies often need SameSite.

Why does column 2 look inverted from hostOnly?

Netscape stores include-subdomains. TRUE means not host-only. CookieMan JSON stores hostOnly directly.

Which format should I commit to a test repo?

JSON Array with fake values, never live sessions. If the test runner is curl, generate Netscape in CI from that JSON.

JSON Array vs cookies.txt Field Mapping

JSON Array vs cookies.txt: every field that is lost

JSON Array vs cookies.txt is a lossy conversion: seven tab-separated Netscape columns cannot hold sameSite or partitionKey. Use the converter below to see the rewritten file, then keep JSON when Chrome has to re-import the same flags.

Pick JSON Array for backups and browser import. Pick Netscape only for curl, wget, yt-dlp and MozillaCookieJar.

JSON vs cookies.txtcookies.txt field mappingJSON Array Netscapecookie format comparison

1
Start from JSON Array
Export from CookieMan with JSON Array — the only lossless format among the six.
2
Convert both ways here
Paste JSON, output Netscape, inspect the table below against the file. Paste the Netscape back with output JSON to see sameSite become unspecified.
3
Choose the consumer
Chrome Import → keep JSON. curl -b → keep Netscape. Do not round-trip through Netscape if SameSite matters.

Paste JSON Array

Output format

Output

Cookies are credentials. Conversion stays in this page — delete the file when you are done.

Field-by-field mapping

What survives JSON Array ⇄ Netscape

JSON Array	Netscape	Round-trip?
`name`, `value`	columns 6–7	Yes
`domain`	column 1 (optional `#HttpOnly_` prefix)	Yes
`hostOnly`	column 2 inverted (FALSE = host-only)	Yes
`path`	column 3	Yes
`secure`	column 4 TRUE/FALSE	Yes
`expirationDate` seconds	column 5; session → `0`	Yes, if not milliseconds
`httpOnly`	`#HttpOnly_` prefix	Yes with a prefix-aware reader
`sameSite`	none	No — always unspecified after Netscape
`partitionKey.topLevelSite`	none	No
`url` (derived)	none	Rebuilt from domain/path/secure

A round-trip JSON → Netscape → JSON is not identity. SameSite and CHIPS keys are gone. That is a format limit, not a UI bug.

When each format wins

JSON Array — Chrome import, backups, Playwright/Puppeteer fixtures that need SameSite.
Netscape — curl, wget, yt-dlp, Requests MozillaCookieJar.
Never Netscape — partitioned cookies, SameSite=None that must stick in Chrome.

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