Bytepad — Markdown notepad and developer toolbox in your browser
# about bytepad
Bytepad is a Markdown notepad with a developer toolbox attached. Open the page and you get a distraction-free editor with live preview and syntax-highlighted code blocks, a searchable list of notes down the side, and word and character counts in the status line. Notes are saved to IndexedDB as you type — no save button, no account, no sync service in the middle. Alongside the editor sit the five conversions you reach for a dozen times a day: Base64 encode and decode, JSON format and validate, UUID v4 generation, Unix timestamp conversion, and HEX/RGB/HSL colour conversion, each one keyboard-reachable from the terminal-style bar at the top of every page.
Everything runs locally. There is no backend, no upload step and no server-side processing: the page is static, the tools are JavaScript, and your notes and pasted payloads stay inside this browser profile. That is what makes Bytepad safe to use with an internal API response, a production configuration file or a customer record — the kind of text you would never paste into an unknown online converter. Once a page has loaded it also keeps working without a network connection. The guides below go deeper on the formats behind the tools: how Base64 padding works, why Unix timestamps and time zones drift apart, and which UUID version belongs in a database key.
# guides
Longer reads on the formats these tools handle: how Base64 padding works, why timestamps and time zones drift apart, and which UUID version belongs in a database key.
Base64 explained: padding, URL-safe, data URIs
How three bytes become four characters, what the equals signs mean, when to use the URL-safe alphabet, and what the 33% overhead costs.
[8 min read] read →
Unix timestamps, time zones and the 2038 problem
Epoch seconds versus milliseconds, why 2038 still matters, how UTC and local time relate, and the daylight-saving traps that break dates.
[9 min read] read →
UUID versions explained: v1, v4 and v7
What the 128 bits contain, how likely a v4 collision really is, why v7 sorts by time, and how the version changes index and storage cost.
[9 min read] read →
# frequently asked questions
Do my notes or pasted text ever leave the browser?
No. Bytepad is a static site with no backend and no analytics that reads your content. Notes are written to IndexedDB, a storage area private to this domain inside your browser, and every tool — Base64, JSON, UUID, timestamps, colors — runs as JavaScript on the page. Nothing is uploaded, so you can safely paste a production config, an internal payload or a customer record.
What happens to my notes if I clear the browser data?
They are deleted. IndexedDB lives with the rest of the site data, so clearing site data, using a private window that you then close, or resetting the browser profile removes the notes permanently — there is no server copy to restore from. Notes are also per-browser and per-device: they do not sync to your phone. For anything you cannot afford to lose, copy the Markdown into a file or a repository.
Does Bytepad work offline?
Once the page has loaded, yes. The editor and the tools are plain client-side JavaScript, so they keep working when the network drops — useful on a plane, in a data centre or on a locked-down machine. You do need a connection for the first load of each page, since the site is served as static files rather than installed as an application.
Which tools are included?
Six, reachable from the header bar: a Markdown notepad with live preview and syntax highlighting, a UTF-8-safe Base64 encoder and decoder, a JSON formatter and validator that reports the line and column of an error, a bulk UUID v4 generator, a Unix timestamp converter that handles seconds and milliseconds in both directions, and a HEX/RGB/HSL color converter with a generated shade palette.
Is the Base64 encoder safe for non-Latin text and emoji?
Yes. The browser primitives btoa and atob predate Unicode and throw on any character above code point 255, which is why many online encoders mangle Cyrillic, Chinese or emoji. Bytepad converts text to UTF-8 bytes with TextEncoder before encoding and decodes back the same way, so the round trip is lossless for any input.
Are the generated UUIDs cryptographically random?
Yes. The generator calls crypto.randomUUID(), the Web Crypto function that returns a version 4 UUID built from the platform cryptographically secure random source — never Math.random(). Each value carries 122 random bits, which makes collisions irrelevant at any realistic scale. You can generate them one at a time or in bulk, with optional uppercase and dash-free output.
Does the timestamp converter understand milliseconds and time zones?
It auto-detects the unit from the number of digits — a ten-digit value is seconds, a thirteen-digit value is milliseconds — and tells you which one it used. Results are shown in UTC and in your browser's local time side by side, together with a relative description such as three hours ago, so you can sanity-check a log line without doing the offset arithmetic yourself.
Is Bytepad free, and do I need an account?
It is free and there is no account, no sign-up and no paywalled tier. Because there is no backend, there is nothing to register for — open a tool and use it. The site is built and maintained by Interhive OÜ, an Estonian company, and the privacy policy linked in the footer describes exactly what is and is not collected.