Inspect a token
Decode a compact JWT to read its fields, then inspect timestamp claims with explicit units. Neither operation verifies authenticity or grants access.
THE DEVELOPER TOOLS COLLECTION
Developer Tools
Test regex, decode JWTs, generate UUIDs and SHA hashes, and convert timestamps or number bases. Inspect results with explicit rules and local processing.
6 tools
Regex TesterInspect JavaScript regex matches, capture groups and positions.Developer ToolsJWT DecoderRead a token’s JSON header and payload without claiming verification.Developer ToolsUUID GeneratorGenerate one or a batch of random version-4 UUIDs.Developer ToolsSHA Hash GeneratorFingerprint exact UTF-8 text with SHA-256, SHA-384 or SHA-512.Developer ToolsUnix Timestamp ConverterConvert epoch seconds or milliseconds and explicitly zoned dates.Developer ToolsNumber Base ConverterConvert exact signed integers between binary, octal, decimal and hex.Developer Tools
No matching tools
Try a broader task such as “text”, “CSV” or “image”. Try a specific task such as regex, timestamp or JSON.
Suggest a taskChoose a tool for the value you have
These tools inspect representations, generate identifiers and test patterns. They work with pasted data in the browser, using explicit units and algorithms so a result can be checked against the system that will receive it.
Inspect tokens and timestamps
JWT Decoder reads header and payload JSON and labels the result unverified. It does not authenticate the token. Take a NumericDate claim to Unix Timestamp Converter to inspect its UTC instant, selecting seconds or milliseconds deliberately. Use the existing Base64 tool for encoded text that is not a JWT.
Generate or compare representations
UUID Generator creates random version-4 identifiers. SHA Hash Generator instead computes a deterministic fingerprint of exact UTF-8 text. One creates a new identifier; the other describes supplied content. Neither grants authorization or replaces a password system.
Number Base Converter changes an integer between binary, octal, decimal and hexadecimal without rounding large values. It does not guess a bit width or turn negative values into fixed-width two’s complement.
Test extraction rules against examples
Regex Tester exposes JavaScript matches, captures and positions. Start with a short representative sample, including examples that should fail. A cancellable worker limits a slow pattern’s run time. For a known fixed string, the existing literal replacement tool is a simpler operation.
Results stay in the page until you copy, download, reset or leave. No input is sent to an external processing API. The website still requests its own pages and scripts, and exporting creates copies you control. Read the API inspection workflow for the difference between reading a value, converting it and verifying it.
START WITH YOUR PROBLEM
Inspect the value. Understand the rule.
Choose the right representation
Generate random v4 identifiers, fingerprint exact UTF-8 text or convert a signed integer between four bases. Choose based on the task, not similar-looking output.
Test a matching rule
Use JavaScript regex matches and captures to test a pattern on good and bad examples. Cancel slow patterns and use literal replacement for fixed text.