# Cookie converter: Netscape and JSON

> Convert cookies between Netscape cookies.txt, JSON and the header form. Runs entirely in your browser — nothing you paste is uploaded or stored.

Source: https://mosaicbrowser.com/tools/cookie-converter

## Cookie converter: Netscape and JSON

Convert cookies between the Netscape `cookies.txt` format, the JSON array that cookie-editor extensions export, a `{ cookies: [...] }` object, a Playwright `storageState`, and a `Cookie:` header line. The input format is detected for you, and every field is carried across. It runs entirely in your browser — nothing you paste is uploaded or stored.

**Cookies are credentials.** That is why this runs on your machine and sends nothing. A row that cannot be read is listed by its line number rather than dropped — a cookie silently skipped is a login that silently does not work.

## What each shape holds

All of them store the same thing — name, value, domain, path, and the flags that decide when a browser sends the cookie — but they spell it differently. The converter reads the fields out of one and writes them into another without losing `secure`, `httpOnly`, `sameSite` or the expiry.

### Netscape cookies.txt

Seven tab-separated fields per line, used by curl and wget. A `#HttpOnly_` prefix on the domain marks an HttpOnly cookie; expiry `0` means a session cookie.

### JSON array

What cookie-editor and EditThisCookie export: one object per cookie with `name`, `value`, `domain`, `expirationDate` and the flags.

### storageState / object

Playwright’s `storageState` and the `{ cookies: [...] }` shape many tools import, including Mosaic.

### Cookie header

The `name=value; name=value` line a browser sends. It has no domain or flags, so converting from it needs a domain you supply.

1. **Paste your cookies.** Paste a Netscape cookies.txt file, a JSON array from a cookie-editor extension, a { cookies: [...] } object, or a Cookie: header line.
2. **Pick the output.** Choose the format you want out. The input format is detected for you, and every field — secure, httpOnly, sameSite, expiry — is carried across.
3. **Copy the result.** Copy the converted cookies. Rows that cannot be read are listed by line number rather than dropped silently.

### Does this cookie converter upload my cookies?

No. The conversion runs entirely in your browser; nothing you paste leaves the page or is stored. Cookies are credentials, so this matters — keep them to yourself.

### Which formats does it read and write?

Netscape cookies.txt (the tab-separated format, with #HttpOnly_ honoured), a JSON array from cookie-editor extensions, a { cookies: [...] } object, a Playwright storageState, and a Cookie: header line. It converts between them and keeps secure, httpOnly, sameSite and expiry.

### What happens to a malformed row?

It is listed by line number rather than dropped. A cookie silently skipped is a login that silently does not work, so the tool names what it could not read, the same rule Mosaic uses when it imports a jar.

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