Base64 and Unicode: A Round-Trip Test
What happens when plain ASCII, accents, emoji, and non-Latin text are encoded and decoded.
Tested 2026-07-18 · Method: 6 UTF-8 strings encoded and decoded in-browser · By Dionis Ceban
Bottom line: The safest workflow makes normalization choices explicit, checks a small sample first, and keeps a human review step for meaning-sensitive changes.
Test matrix
| Input or approach | Operation | Observed result |
|---|---|---|
| Hello | ASCII | Exact round trip |
| Café | Accented Latin | Exact UTF-8 round trip |
| Salut 👋 | Emoji | Exact UTF-8 round trip |
| Привет | Cyrillic | Exact UTF-8 round trip |
Recommended workflow
- Treat Base64 as encoding, not encryption.
- Keep the same character encoding on both sides; this site uses UTF-8.
- Decode a sample before moving a large payload.
- Do not paste secrets into third-party systems merely because they are Base64-encoded.
How to reproduce this test
Copy the examples from the matrix into the relevant tool, apply only the named setting, and compare the output character by character. Browser and operating-system differences should not affect these JavaScript text operations.
What this test does not prove
This is a focused behavior test, not a guarantee for every document. Language rules, proprietary file formats, personally identifying data, and search-engine rendering all require context-specific review.