nanoid vs uuid

utility

nanoid

uuid

Nanoid and UUID are JavaScript libraries for generating unique identifiers, but they serve different philosophical approaches. UUID is the established RFC 4122 standard that has been the go-to solution for distributed systems and enterprise applications for decades, offering standardized formats (v1, v4, v5) with 128-bit identifiers. Nanoid is a modern alternative that prioritizes performance and bundle size, generating cryptographically secure 21-character URL-safe IDs by default with a smaller footprint and faster generation speed.

This comparison matters because unique ID generation is a foundational requirement in modern web applications—from database keys to session tokens to tracking identifiers. UUID targets enterprise developers, distributed system architects, and teams requiring cross-platform standardization and regulatory compliance. Nanoid appeals to frontend developers, performance-conscious teams, and projects where bundle size impacts load time, particularly in client-side applications where every kilobyte matters.

Head-to-Head

Performance & Generation Speed→ nanoid wins

nanoid

Generates IDs 60-65% faster than UUID due to optimized algorithm and smaller output size. The performance advantage is particularly noticeable when generating IDs in tight loops or high-throughput scenarios.

uuid

Slower generation speed compared to nanoid, though still performant enough for most applications. The overhead comes from generating 128-bit values and formatting them with hyphens into the standard 36-character string.

Bundle Size Impact→ nanoid wins

nanoid

Extremely lightweight at 108 bytes minified. This makes it 4.5 times smaller than UUID and ideal for client-side applications where JavaScript bundle size directly impacts page load performance and user experience.

uuid

Larger footprint due to supporting multiple UUID versions and formatting options. While not enormous, the size difference is significant for applications optimizing for performance budgets or targeting slower networks.

Standardization & Interoperability→ uuid wins

nanoid

Not an industry standard—it's a custom format that won't be recognized by external systems expecting RFC 4122 UUIDs. This can create integration challenges when working with third-party APIs, databases, or legacy systems.

uuid

RFC 4122 compliant standard recognized globally across programming languages, databases, and systems. APIs and external services often explicitly require or expect UUID format, making it the safe choice for interoperability.

URL Safety & String Format→ nanoid wins

nanoid

URL-safe by default using A-Za-z0-9_- characters without hyphens, making IDs 21 characters long. Perfect for embedding in URLs, filenames, or HTML attributes without encoding. Shorter length also reduces storage and bandwidth requirements.

uuid

Contains hyphens that are URL-safe but not URL-friendly in all contexts. The 36-character length (including hyphens) takes up more space in URLs, databases, and logs. Some implementations require parsing the hyphen format.

API Simplicity & Developer Experience→ nanoid wins

nanoid

Extremely simple API: import nanoid and call it. Supports optional length parameter for customization. No version selection or configuration needed for basic use, making it immediately accessible to junior developers.

uuid

Requires choosing between versions (v1, v4, v5) with different characteristics—v1 includes timestamp and MAC address, v4 is random, v5 is namespace-based. This flexibility adds cognitive overhead for developers unfamiliar with the distinctions.

Collision Resistance & Securitytie

nanoid

2^126 possible IDs (~9.5 × 10^37) with 21-character default length. Uses cryptographically strong random number generator. Collision probability is negligible for practical applications—you'd need to generate 1 million IDs per second for ~4 million years to have a 1% collision chance.

uuid

2^128 possible IDs (~3.4 × 10^38) providing slightly more entropy than nanoid. The difference is theoretically measurable but practically irrelevant—both offer sufficient collision resistance for any real-world application. UUID v4 also uses cryptographic randomness.

Verdict

For modern web applications, particularly those running client-side or optimizing for performance, nanoid is the superior choice. Its significantly smaller bundle size, faster generation speed, and URL-friendly format make it ideal for the majority of contemporary JavaScript projects. The performance and size advantages are real and measurable, not marginal improvements. The only meaningful tradeoff is lack of standardization, which only matters in specific enterprise contexts.

Choose UUID when you're working in enterprise environments requiring RFC 4122 compliance, integrating with systems that explicitly expect UUID format, or building distributed systems where standardization across multiple languages and platforms is non-negotiable. Choose nanoid for everything else: SPAs, mobile apps, microservices where you control both ends, and any project where performance and bundle size are priorities. If you're building a greenfield project with no external UUID requirements, nanoid is the pragmatic modern choice.

When to Use Each

If you are building a React/Vue/Svelte SPA that generates client-side IDs for tracking user interactions → use nanoid because the 4.5x smaller bundle size directly improves initial load time and the 60% faster generation won't block the main thread during bulk operations.

If you are integrating with external APIs or enterprise systems that require RFC 4122 compliant identifiers in their documentation → use uuid because attempting to use nanoid will result in validation errors or rejected requests, and standardization is non-negotiable.

If you are building a REST API that generates short-lived session tokens or tracking IDs embedded in URLs → use nanoid because the URL-safe format eliminates encoding issues and the shorter 21-character length keeps URLs cleaner and reduces bandwidth.

If you are working on a multi-language distributed system with services in Java, Python, and JavaScript that all need to generate compatible identifiers → use uuid because it's the only format with native library support across all major languages and databases.

Learn More

nanoid →uuid →

Head-to-Head

Performance & Generation Speed→ nanoid wins

nanoid

uuid

Bundle Size Impact→ nanoid wins

nanoid

uuid

Standardization & Interoperability→ uuid wins

nanoid

uuid

URL Safety & String Format→ nanoid wins

nanoid

uuid

API Simplicity & Developer Experience→ nanoid wins

nanoid

uuid

Collision Resistance & Securitytie

nanoid

uuid

Verdict

When to Use Each