UUID Format Converter

No. Format conversion only changes the textual representation, not the underlying 128-bit value. All formats represent the exact same UUID. Converting between formats is like writing the same number in different notations (123 vs 0x7B)—the value is identical, only the display changes. The UUID remains functionally equivalent across all formats.

Use native UUID types when available (PostgreSQL UUID, SQL Server UNIQUEIDENTIFIER) which handle format internally. For databases without native support: use BINARY(16) with compact format for space efficiency, or CHAR(36) with canonical lowercase for readability and debugging. Document your choice and be consistent across your application to avoid conversion overhead and confusion.

Yes, they're the same UUID. However, some systems treat them as different strings in comparisons. Best practice: normalize to lowercase canonical format for storage and comparison to prevent duplicates. For example, without normalization, you might accidentally treat "550E8400-..." and "550e8400-..." as different records in case-sensitive systems.

Depends on your database. PostgreSQL's UUID type accepts any valid format and normalizes automatically. For string columns (CHAR/ VARCHAR), normalize to your standard format before insertion for consistency. For BINARY columns, convert to compact format and then to binary. Consistent formatting prevents query issues and duplicate key violations from format differences.

APIs enforce format standards for consistency and parsing reliability. Strict APIs may only accept canonical lowercase hyphenated format, rejecting uppercase, compact, or braced variants. This ensures predictable parsing and prevents ambiguity. Always check API documentation for format requirements and convert accordingly before making requests.

Most languages provide UUID libraries with format conversion: JavaScript uuid library has formatting options, Python uuid module supports str() and hex properties, Java's UUID class has toString(), C#'s Guid has ToString(format). For custom formats, normalize to lowercase, remove/add hyphens as needed, and wrap with prefixes/ suffixes. Regex can help but libraries are more reliable.

Slightly. Compact format saves 4 bytes per UUID, reducing storage and network transfer costs at scale. Binary storage (16 bytes) is most efficient. String formats have similar performance for comparison operations. The real performance impact comes from indexing strategies (time-ordered vs random UUIDs), not format choice. Choose format based on compatibility and readability, not performance.

Use URN format when UUIDs need to be formal URIs in semantic web contexts, RDF/OWL ontologies, XML namespaces, or specifications requiring full URI notation. For regular APIs and databases, stick to canonical hyphenated format. URN format is verbose and mainly for formal/academic contexts where URIs are required, not everyday application development.

Yes, format conversion is lossless and repeatable. Converting canonical → compact → uppercase → URN → braced → back to canonical yields the exact same UUID. There's no degradation or loss of information. However, repeated conversions waste CPU cycles. Convert once at system boundaries and store in your preferred format to avoid unnecessary processing.

Mixing formats causes problems: duplicate records (same UUID in different formats treated as different values), failed queries (searching for lowercase doesn't find uppercase), broken foreign key relationships, and debugging nightmares. Always normalize to one format at input boundaries. Use database constraints or triggers to enforce format consistency. Better yet, use native UUID types that handle this automatically.