Convert UUID bytes to compact Base64/Base64URL locally with optional padding.
See standard and URL-safe alphabets in padded and unpadded forms together, plus the raw UUID bytes and a decode round-trip check.
UUIDs are 128-bit values. Version meaning is interpreted only inside the appropriate variant, and representation conversion never changes the underlying 16 bytes.
Use the tool first, then apply these checks to verify inputs, interpret the result, and hand it off without displacing the primary workflow.
A canonical UUID string represents 16 bytes written as hexadecimal groups with hyphens. A UUID-to-Base64 conversion should parse those 32 hexadecimal digits into the underlying 16 bytes before encoding. Base64-encoding the 36-character text string produces a different value, so record which representation is being converted when comparing results across tools.
Standard Base64 uses + and / and normally includes = padding, while Base64URL replaces those characters with - and _ and is often unpadded. Both can represent the same 16 UUID bytes. Match the variant required by the API, database, token format, or URL you are integrating with instead of assuming the strings are interchangeable.
For a migration or compact-key workflow, decode the Base64 value back to 16 bytes and reconstruct the canonical UUID. A successful round trip should reproduce the same hexadecimal UUID exactly. This catches a wrong alphabet, missing or mishandled padding, text-encoding mistakes, and accidental conversion of the displayed UUID characters instead of its bytes.
The encoded length and alphabet describe the byte representation, not the semantic UUID version. If version or variant matters, inspect the UUID bits after decoding. Treat Base64 as a transport representation only; it does not add randomness, secrecy, validation, or authenticity to the identifier.
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