Frequently asked questions

Plain answers about how Hermet works.

What is Hermet?

A bundle of developer tools — JSON formatting and repair, conversion to CSV and TypeScript, a JWT decoder, Base64 and URL encoding, UUIDs and timestamps — that run entirely in your browser. There is no Hermet server processing your input; the tool pages make zero network requests.

Do the tools upload my data?

No. Everything you paste is processed on this device and nowhere else. You can check: open your browser’s Network tab, reload a tool page, and use the tool — no request carries your data, because no request is made at all. Each tool page is also served with a Content Security Policy of connect-src 'none', so the browser itself is forbidden from sending data anywhere. Turning on airplane mode after a page loads changes nothing: the tools still work.

Do I need an account?

Not for the tools. They are free, with no sign-up. An account exists only for Pro billing, on the Account page — the one page that talks to a server, along with the Pro checkout.

How does sign-in work?

With an email link or a 6-digit email code — there is no password. Our sign-in provider, Supabase, stores your email address and a record of your plan. Sign in on the Account page.

What does Pro add?

Batch processing (many files in one run, on the formatter, CSV converter and type generator), large-file mode on the JSON Formatter (pastes over 512 KB are formatted in a background worker so the page never freezes), saved workspaces, and the installable offline app. Pro is $5/month or $39/year. The tools themselves stay free. See the Pro page.

Where are my workspaces stored?

In this browser, on this device, in its local storage. They are never uploaded and never synced. Clearing this site’s data in your browser deletes them.

Which pages talk to a server?

Only two: the Account page (sign-in and your plan, via Supabase) and the Pro checkout (payment, handled by Paddle, our seller of record). No tool page talks to any server.

How do I cancel Pro?

Use the link in your Paddle receipt email — it opens your subscription page at Paddle. You keep Pro until the end of the period you paid for, and you are not charged again. See the refund policy.

How do I contact you?

Email [email protected], or see the Contact page.