Nano ID Frequently Asked Questions
What is Nano ID?
Nano ID is a small, secure, URL-friendly library for generating unique identifiers. It creates compact random IDs using a customizable alphabet and cryptographically secure random numbers.
A typical Nano ID looks like this:
V1StGXR8_Z5jdHi6B-myT
By default, Nano ID generates 21-character identifiers that provide collision resistance comparable to UUIDv4.
Why was Nano ID created?
Nano ID was created to provide a modern alternative to UUIDs that is:
- shorter
- URL-friendly
- cryptographically secure
- highly customizable
- lightweight
- fast to generate
Its primary goal was to reduce identifier length while maintaining an extremely low probability of collisions.
How long is a Nano ID?
By default, a Nano ID is 21 characters long.
Unlike UUIDs, the length is configurable. Developers can generate identifiers that are shorter or longer depending on their application's requirements.
What characters does Nano ID use?
The default alphabet contains 64 URL-safe characters:
A-Z
a-z
0-9
_
-
Since only URL-safe characters are used, Nano IDs do not require URL encoding.
Is Nano ID unique?
Yes.
Nano ID provides statistical uniqueness using cryptographically secure random numbers.
A default 21-character Nano ID has approximately the same collision probability as a UUIDv4.
Can two Nano IDs be identical?
Yes, but the probability is extraordinarily small.
With the default settings, billions of Nano IDs can be generated before the chance of a collision becomes significant.
Is Nano ID cryptographically secure?
Yes.
Nano ID uses cryptographically secure random number generators provided by the operating system or runtime.
Examples include:
- Web Crypto API
- Node.js
crypto - modern browser cryptography APIs
Is Nano ID suitable for URLs?
Yes.
Nano ID was specifically designed for use in URLs.
Benefits include:
- only URL-safe characters
- no URL encoding required
- shorter than UUIDs
- easy to read
- easy to copy and paste
Example:
https://example.com/users/V1StGXR8_Z5jdHi6B-myT
Is Nano ID suitable for filenames?
Yes.
Nano IDs contain only letters, digits, underscores, and hyphens, making them safe for filenames on Windows, Linux, and macOS.
Example:
photo-V1StGXR8_Z5jdHi6B-myT.jpg
Is Nano ID sortable?
No.
Nano IDs are generated using random data and do not include a timestamp.
Sorting Nano IDs alphabetically does not produce creation order.
If sortable identifiers are required, UUIDv7 or ULID are better choices.
Is Nano ID suitable for databases?
Yes.
Nano IDs work well as unique identifiers and database primary keys.
However, because they are random, they have similar indexing characteristics to UUIDv4. New rows are inserted throughout an index rather than sequentially, which may increase fragmentation in write-heavy databases.
Is Nano ID suitable as a primary key?
Yes.
Many applications use Nano IDs as primary keys because they provide:
- decentralized generation
- globally unique identifiers
- compact text representation
- excellent API compatibility
Applications requiring sequential inserts may benefit more from UUIDv7 or ULID.
Can Nano ID replace UUIDs?
In many applications, yes.
Nano ID provides similar collision resistance while producing significantly shorter identifiers.
However, Nano ID is not compatible with the UUID standard and uses a completely different format.
Can I customize the alphabet?
Yes.
Nano ID allows developers to define a custom alphabet.
For example, identifiers can be generated using only:
- hexadecimal characters
- digits
- uppercase letters
- lowercase letters
- any custom character set
Can I customize the length?
Yes.
Nano ID supports almost any identifier length.
Longer identifiers reduce collision probability, while shorter identifiers improve readability and reduce storage requirements.
Can Nano ID be generated offline?
Yes.
Nano ID generation requires only a cryptographically secure random number generator.
No internet connection or central authority is required.
Does Nano ID reveal personal information?
No.
Nano IDs contain only random data.
They do not include:
- timestamps
- MAC addresses
- IP addresses
- usernames
- hardware identifiers
Can Nano IDs be guessed?
Not realistically.
Properly generated Nano IDs contain enough randomness to make brute-force guessing computationally impractical.
They should not be used as passwords, session secrets, or authentication tokens.
Which programming languages support Nano ID?
Nano ID implementations are available for many languages, including:
- JavaScript
- TypeScript
- Node.js
- Python
- Java
- C#
- Go
- Rust
- PHP
- Ruby
- Swift
- Kotlin
Most implementations generate compatible identifiers.
How does Nano ID compare to UUIDv4?
| Feature | Nano ID | UUIDv4 |
|---|---|---|
| Default length | 21 characters | 36 characters |
| URL-friendly | Excellent | Good |
| Sortable | No | No |
| Timestamp | No | No |
| Random | Yes | Yes |
| Official standard | No | Yes |
How does Nano ID compare to UUIDv7?
| Feature | Nano ID | UUIDv7 |
|---|---|---|
| Default length | 21 characters | 36 characters |
| URL-friendly | Excellent | Good |
| Sortable | No | Yes |
| Timestamp | No | Yes |
| Database performance | Good | Excellent |
| Official standard | No | Yes |
UUIDv7 is the better choice for chronological ordering and database indexing, while Nano ID is ideal when compact, URL-friendly identifiers are the primary goal.
Should I choose Nano ID, UUIDv7, or ULID?
| Feature | Nano ID | UUIDv7 | ULID |
|---|---|---|---|
| Default length | 21 | 36 | 26 |
| URL-friendly | Excellent | Good | Excellent |
| Sortable | No | Yes | Yes |
| Timestamp | No | Yes | Yes |
| Database performance | Good | Excellent | Excellent |
| Official standard | No | Yes | No |
Choose Nano ID if you want compact, URL-friendly identifiers with excellent randomness.
Choose UUIDv7 if you want an official standard that is optimized for databases and chronological ordering.
Choose ULID if you want a shorter, sortable identifier with excellent readability.