Meet UUID & NanoID: Safe Unique IDs for Modern Systems

In many modern projects, generating truly unique IDs is no longer as simple as incrementing a number in the database. We have to deal with:

• Multiple services writing data at the same time
• Background workers and message queues
• Offline-first applications that sync later

At that point, relying on AUTO_INCREMENT starts to feel risky. That is where UUID and NanoID become extremely useful.

This article looks at:

• The practical differences between UUID and NanoID
• When to choose each one
• Common risks when designing ID schemes
• How a simple generator can speed up your everyday workflow

Why Unique IDs Matter So Much Today

When your app has a single server and a single database, ID collisions might be rare. But as soon as you scale out, new problems appear:

• Several services create records independently
• Background jobs also generate their own data
• Some data is created while devices are offline

Without a solid ID strategy, you may face:

• Records overwriting each other because of primary key collisions
• Difficulty tracing events across logs and services
• Complicated offline sync because IDs need to be remapped

UUID and NanoID move the responsibility of “uniqueness” from the database to a dedicated ID generator, designed for exactly this purpose.

A Quick Look at UUID

UUID (Universally Unique Identifier) is a 128-bit identifier, usually represented as a string like:

• 550e8400-e29b-41d4-a716-446655440000

Key characteristics:

• Fixed length and easy to recognize
• Well supported in almost every programming language
• Not easily guessable in sequence

Where UUID shines:

• Systems that need globally unique IDs across services
• Reference IDs in logs, tracing, and third-party integrations
• Situations where cross-platform consistency matters

Trade-offs:

• Quite long to store and send repeatedly
• When used as a primary key in large tables, index size and fragmentation must be considered.

A Quick Look at NanoID

NanoID is a more modern, compact alternative to random IDs.

Example:

• V1StGXR8_Z5jdHi6B-myT

Characteristics:

• Default length is shorter than a UUID but still offers high entropy
• Customizable alphabet (e.g., upper-case letters + digits only)
• Designed to be fast and suitable for both frontend and backend environments

Benefits:

• Great for URLs, QR codes, referral codes, and anything user-facing
• Smaller JSON payloads compared to 36-character UUIDs
• Flexible: you can tune length and alphabet to match your collision risk tolerance

Things to watch out for:

• Do not randomly change length or alphabet without understanding the impact on collision probability
• Teams need a clear standard so every service uses the same configuration.

When Should You Use UUID vs NanoID?

There is no single answer for every system, but this rule of thumb works well:

Choose UUID when:

• You need broad compatibility with libraries, databases, and monitoring tools
• You integrate with third parties that already expect UUID format
• IDs are more important for backend & logs than for human-facing UX

Choose NanoID when:

• IDs will frequently appear in URLs, UI, or QR codes
• You want shorter IDs that are still hard to guess
• Your apps run in both frontend (JavaScript/TypeScript) and backend

The key is to pick one scheme per entity type and stay consistent across services.

Common Pitfalls in ID Design

Here are mistakes we see often in real projects:

1. Mixing too many ID types
   Some data uses integer autoincrement, others use UUID, others NanoID. It feels flexible at first but complicates queries, logging, and documentation.

2. Relying on timestamps alone
   For example, using 20251206123456 as an ID. In distributed systems, different events can easily share the same timestamp.

3. Predictable IDs in public systems
   For public links or registration codes, sequential IDs can expose other users’ data.

4. No central guidelines
   Different teams choose their own libraries and lengths. Over time, there is no guarantee of consistency across the ecosystem.

UUID and NanoID will not magically solve all problems, but they give you a solid foundation when used consistently.

A Practical Workflow for Using UUID/NanoID

Instead of rethinking ID schemes for every new feature, establish a simple team workflow:

1. Define the team standard

   • Which entities (user, order, invoice) use which ID type? UUID v4? NanoID length 21?
   • What are the naming rules? (id, user_id, order_id)

2. Provide an easy generator
   Beyond libraries in code, a browser-based tool helps you:

   • Generate sample IDs for tests
   • Fill in example payloads in API docs
   • Experiment with formats before hardcoding them in seed data

3. Use this scheme from day one
   Migrating from integers to UUID/NanoID later is painful. It is usually better to start with a scheme that is “future-proof”.

Try the UUID & NanoID Generator From SO-NO

As part of our Developer Tools collection, we built a UUID & NanoID Generator that runs directly in your browser.

It is designed so you can:

• Generate multiple IDs at once for testing
• Choose between UUID v4 and NanoID as needed
• Copy the results quickly into code, documentation, or API requests

If you frequently need unique IDs from many different contexts, feel free to try the tool:

Use the UUID & NanoID Generator

Hopefully this article helps you design safer, more consistent ID strategies — and spend less time worrying about collisions while your system continues to grow.