Toolstead
Small, focused tools for everyday developer chores — no sign-up, no upload, no tracking. Open DevTools and watch the Network panel: converting anything produces zero requests.
Encoding
Base64 to Image
Paste any Base64 — prefixed, raw, wrapped, URL-safe or broken — and see the image.
Image to Base64
Get the exact string you need: Data URI, plain Base64, CSS, HTML or JSON.
Raw Base64 Decoder
No data: prefix required. The format is read from the bytes, not the label.
URL-safe Base64 to Image
Handles the - and _ alphabet used by JWTs, cookies and query parameters.
Base64 to PNG
Decode a raw string straight to a .png file, transparency preserved.
Base64 to JPG
Recognise a JPEG by its FF D8 FF signature, even without a prefix.
PNG to Base64
Encode a transparent PNG into a Data URI ready for CSS or JSON.
JPG to Base64 for CSS
Wrapped and quoted for a stylesheet or an email template.
URL Encoder / Decoder
Percent-encoding done right, including the + versus %20 question.
Ascii85 Encoder
Encode text or hex bytes to Ascii85, or decode it back — with the Adobe <~ ~> wrapper handled, not guessed.
Hardware
Images
Guides
Everything that tends to go wrong when you move an image through Base64 — and how to fix it.
MIFARE Classic Sector Dump: What the Hex Actually Says
Sixteen bytes per block, one trailer per sector, and a UID stored backwards. What a dump really contains, and the three parts people read wrong.
Duplicate URLs: Why One Page Gets Many Addresses
Trailing slashes, percent-encoding case, default ports and query order. Six differences that split one page into six addresses, and how to collapse them.
Why Card Number Formats Differ: Hex, Decimal, Byte Order
One reader prints 04A2243A, another prints 975479300 — and both are right. The four forms a card UID can take, and the step that quietly invents a number.
Percent-Encoding: The Reserved Characters That Break URLs
Reserved means the character has a job in that position. Leave it unencoded in a value and it splits your data into parameters or fragments, with no error.
Why these tools are built this way
Your data never leaves the browser. Every tool here runs entirely client-side. There is no backend to send anything to — that is the reason the page keeps working when the network drops, and why a 5 MB image convert produces no requests at all.
Failures get explained, not just reported. The Base64 tools do not stop at "invalid input". They tell you the character that broke it, its exact position and code point, whether the length implies truncation, and whether those bytes are gzip rather than an image — then offer a one-click fix where one exists.
Offline by default. The site installs as a PWA, so once a tool has loaded it stays available with the network switched off — useful when you are debugging against an internal service.
No account, no history, no upload. If advertising is introduced later, it will be limited to clearly separated, fixed-height slots that never cover the working area.