ガイド
Base64とURLエンコードの違い
用途の異なる2つのエンコードを正しく使い分けるためのガイドです。
Base64とURLエンコードは解決する問題が異なります。混同するとリンクやAPI処理で不具合が出ます。
URL encoding keeps URLs valid
URL encoding escapes reserved characters in URLs.
Use it for query params, path segments, and redirect values.
Base64 changes data into text-safe blocks
Base64 is useful for transporting binary or structured values as text.
It is not a replacement for URL encoding in links.
Common confusion patterns
Developers often Base64 a value and still need URL encoding if it goes into a URL.
Treat these as separate steps when needed.
- URL params: URL encode.
- Binary payloads in text fields: Base64.
- Sensitive data: use encryption, not Base64.
Debugging rule of thumb
If a URL breaks, inspect URL encoding first.
If unreadable blob data appears, decode Base64 to inspect original content.
Useful for
- Building query strings.
- Transferring binary data in text channels.
- Debugging API parameters.
- Encoding values in redirects.
Choose encoding by purpose
URL encoding protects URL characters. Base64 converts data representation. Use the right one for the job.