Ling.Tools

Security & tokens / LING.TOOLS

JWT encoder & decoder

Decode JWT claims, sign HS256/384/512 tokens, and verify HMAC signatures locally.

Input & settings

01
Configure tool input

Without a secret, decoding does not verify the signature. A valid signature alone does not establish trust. Secrets stay on this device.

Processed in your browser. Your input is never uploaded or saved.

Result

02

Ready when you are

Set up your input and run the tool. Your result will appear right here.

Private · Instant · Local

GUIDE & CONTEXT

About this tool

Decode header and payload without a key, or supply a secret to verify HS256/384/512 signatures. You can also sign a JSON payload with a sufficiently strong key. Signature validity alone does not establish issuer trust, audience or authorization.

How to use it

  1. Choose decode/verify or sign/encode.
  2. For signing, enter header and payload JSON plus a strong secret. For verification, paste a compact JWT and provide its secret.
  3. Review signature and time claims; your application must still validate issuer, audience and authorization.
Example

A payload containing {"exp":1704067200} declares an expiry of 2024-01-01T00:00:00Z, regardless of whether the signature is valid.

Random stringGenerate random strings with selected character groups, a custom alphabet and an option to exclude ambiguous characters.Random hexadecimalCreate random hexadecimal strings in uppercase or lowercase, with adjustable length and batch size.Random numberPick random integers or decimal numbers within a chosen range, with endpoint controls, precision and batch generation.UUID generatorGenerate cryptographically random UUID v4 identifiers in bulk, with uppercase and hyphen formatting options.Password generatorGenerate passwords locally with cryptographic randomness, required character groups, exclusions and batch output.ULID & NanoIDCreate time-sortable ULIDs or compact NanoIDs, including custom NanoID length and alphabet options.Lorem IpsumGenerate Lorem Ipsum placeholder text by word, sentence or paragraph for layout and typography testing.JSON formatterValidate, pretty-print or minify JSON, optionally sort object keys and locate syntax errors in pasted data.YAML ↔ JSONConvert YAML configuration to JSON or JSON to readable YAML using safe parsing without executable custom tags.Base64 / Base64URLEncode Unicode text as Base64 or decode it back to UTF-8, with a URL-safe alphabet for tokens and query values.URL encoderPercent-encode or decode a complete URI or a single URL component, including Unicode and reserved characters.HTML entitiesEscape text as HTML entities or decode entity references, with decoded markup displayed safely as plain text.
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