Developer Toolkit
Small tools for everyday development work in one page. Everything runs in your browser; no data is sent to a server.
About the Developer Toolkit
The TConverter Developer Toolkit gathers six small utilities that developers reach for every day into a single page with tabs: URL encoding, a JWT decoder, a UUID generator, hash calculation, Unix timestamp conversion and a color converter. Instead of searching for a separate site for each quick task, you can switch between tabs and keep working.
The URL Encode tab offers two modes. Component (query value) encodes everything that could break a URL, including &, ?, / and #, which is what you need for a single query parameter. Full URL keeps the structure of an address intact and only encodes characters such as spaces or non-ASCII letters. Decoding also treats + as a space, as used in form data. The JWT Decoder shows a token's header and payload as formatted JSON, converts the exp, iat and nbf claims into readable dates and tells you whether the token has expired. The signature is not verified; the decoder is meant for reading token contents while debugging, not for deciding whether a token can be trusted.
The UUID tab generates between 1 and 100 random version 4 UUIDs at once using the browser's cryptographic random generator. The Hash tab calculates MD5, SHA-1 and SHA-256 together for text or for a file of up to 200 MB, which is handy for comparing a download against a published checksum. SHA-1 and SHA-256 use the browser's built-in WebCrypto API; MD5 is not part of WebCrypto because it is considered insecure, so it is implemented separately for checksum use. MD5 and SHA-1 should not be used for passwords or security purposes.
The Timestamp tab converts Unix timestamps to UTC and local time and automatically detects whether a value is in seconds or milliseconds: values of 13 digits or more are treated as milliseconds. A Now button fills in the current time, and a date picker converts any date and time back to seconds and milliseconds. The Color tab accepts HEX (including the three-digit short form), rgb() and hsl() values or a color picker, and shows the matching HEX, RGB and HSL values with a preview swatch.
Every calculation runs in your browser. Tokens, hashed files and other inputs are never sent to a server. The toolkit is free and needs no account.
Frequently asked questions
Is the JWT signature verified?
No. The tool only decodes the header and payload; it does not verify the signature. A decoded token can still be forged or tampered with, so always verify signatures on your server.
Is it safe to paste a JWT or other sensitive data here?
All tabs run locally in your browser and nothing is sent to a server. As a general habit, still avoid sharing production tokens in places you do not control.
Why is MD5 not available in WebCrypto?
The WebCrypto API intentionally leaves out MD5 because it is cryptographically broken. TConverter computes MD5 with its own implementation so it can still be used for file checksums.
Can I use MD5 or SHA-1 for passwords?
No. MD5 and SHA-1 are only suitable for checksums and integrity checks of non-security-critical data. For password storage, use a dedicated algorithm such as bcrypt or Argon2 on your server.
How does the timestamp tool know whether I entered seconds or milliseconds?
Values with an absolute size of 13 digits or more are treated as milliseconds, smaller values as seconds. The result shows which unit was used.
Which UUID version is generated?
Version 4 UUIDs, created with the browser's crypto.randomUUID function. You can generate up to 100 at a time.