Format, Encode, Generate, Validate: Choosing the Right Tool 日本語ガイド

Developer tools often use similar words for very different jobs. Format, encode, generate, validate, convert, and inspect all sound simple, but choosing the wrong operation can create confusing results.

The fastest workflow starts by naming the operation correctly.

Format: make existing data readable

Formatting changes presentation without changing the meaning of the data. A JSON formatter adds line breaks and indentation, but the object values should stay the same.

Use formatting when the data is already valid and you want to read it, review it, or commit it with cleaner diffs. The JSON Formatter is the clearest example: it can pretty-print, minify, sort keys, and show a tree view for valid JSON.

Encode: represent data for a transport

Encoding changes how data is represented so it can move through a specific system. URL encoding protects reserved characters in URLs. Base64 represents bytes as text. Neither operation means the data is encrypted.

Use URL Encoder / Decoder for query strings, form values, and URI components. Use Base64 Encoder / Decoder for text or file data that needs a transport-safe representation.

Generate: create new data

Generation creates fresh values instead of transforming existing input. A UUID generator creates random identifiers. A password generator creates secrets or passphrases according to selected rules.

Use generation when reusing real data would be risky or messy. The UUID Generator is useful for fixtures and temporary IDs. The Password Generator is useful when you need strong values created by browser cryptography.

Validate: check whether data follows rules

Validation answers a yes-or-no question: does this input follow the expected syntax or schema?

JSON validation checks syntax. JSON Schema validation checks structure and constraints. Timestamp inspection checks whether a number likely represents seconds or milliseconds. Validation is often the first step before formatting or conversion.

Convert: change the shape or unit

Conversion changes one representation into another. A Unix timestamp can become an ISO 8601 date. YAML can become JSON. JSON can become TypeScript types. Conversion is useful when the same information needs to fit another system.

Use the Timestamp Converter when the same moment needs to move between Unix seconds, milliseconds, local time, UTC, and ISO strings.

Escape: make text safe for HTML

HTML escaping is not URL encoding. When API docs, error pages, or SSR templates embed JSON snippets, entity encoding prevents <, >, and & from breaking markup. Use HTML Entity Encoder / Decoder when the boundary is HTML, not transport.

A simple decision rule

Ask what you want to happen to the input:

• Need to read it? Format it.
• Need to send it through a constrained channel? Encode it.
• Need a new value? Generate it.
• Need to know whether it is correct? Validate it.
• Need the same information in another representation? Convert it.

That small distinction saves time and prevents accidental changes to data you only meant to inspect.