A collection of free tools that run in your browser. No account, no upload, no queue.
TinkerLog started as something else. It used to carry product roundups and buying guides — pages recommending a specific air fryer or monitor, with affiliate links attached. Those pages are gone, deliberately. A recommendation with a price in it ages badly, needs constant maintenance to stay honest, and is the kind of writing that quietly stops being true while nobody is watching. What is left is the part that does not rot.
What is left is one hundred and two free tools: calculators, converters, and a set of developer utilities. They do one job each, they do it in the page, and nothing you type into them is sent anywhere.
What that means in practice
- No account. There is nothing to sign up for and no reason to give an email address. Open a tool, use it, close the tab.
- No upload. The work happens in JavaScript on your own machine. When you paste a JSON document into the formatter or a token into the JWT decoder, that text does not travel to a server, because there is no server component to send it to.
- No history. Nothing is logged, so there is no record to leak, subpoena or accidentally publish.
- No dark patterns. No paywall after three uses, no forced newsletter, no “sign in to see the result”.
Why browser-side, and what it costs
The honest trade-off is that everything runs on your device, so very large inputs are limited by your own memory rather than by a server farm. For the sizes these tools are built for — a few megabytes of JSON, one token, a spreadsheet of numbers — that ceiling is not one you will notice. In exchange you get a tool that keeps working offline, cannot rate-limit you, and cannot read what you put in it.
How the writing is made
This is an AI-assisted site, and we would rather say so plainly than let you infer it. The tool copy and the explanations around them are produced with AI assistance, then checked against how the tool actually behaves. That is a real limitation: we are describing tools we built, but we cannot claim the same depth for every general claim on the site that we can for the tools themselves.
Where we are not sure about something, we try to say so rather than round it up to a confident sentence. If you find an error, correcting it is genuinely useful — see below.
Getting in touch
Found a bug, got a wrong answer out of a calculator, or want a tool that is not here yet? Email sunfei0318@gmail.com. Requests for specific tools are the most common thing in the inbox and they do shape what gets built next.