ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_-
64 characters · ~6 bits/char
Ready to generate
Configure options and click Generate// create compact unique ids with configurable alphabet and length
Generate Nano IDs with custom alphabet, length, and quantity. Compact, URL-safe unique identifiers perfect for databases, tokens, and sessions.
Ready to generate
Configure options and click GeneratePick a preset (URL-Safe, Hex, etc.) or enter a custom character set.
Drag the sliders to set ID length (4–128) and how many to generate (1–1000).
Click Generate, then copy or download the IDs in your preferred format.
A Nano ID is a tiny, URL-safe, unique string ID — a modern alternative to UUID. Nano IDs are smaller, faster to generate, and more collision-resistant per character than UUID v4, making them ideal for modern web apps and APIs.
Nano ID is a compact, URL-safe unique string ID generator. It produces shorter IDs than UUID while maintaining strong collision resistance. A 21-character Nano ID using the default alphabet has ~126 bits of entropy — similar to UUID v4.
Higher entropy means lower collision probability. For most applications, 100+ bits of entropy is more than sufficient. This tool shows the estimated entropy for your chosen alphabet and length so you can make an informed decision.
Yes. This tool uses the browser's crypto.getRandomValues() API, which provides cryptographically strong random values — the same source used in TLS/SSL and other security-critical applications.
The URL-Safe preset uses A-Za-z0-9_- — 64 characters. This set is safe in URLs without encoding, in filenames on most operating systems, and in JSON strings without escaping.
The default 21 characters gives ~126 bits of entropy with the URL-Safe alphabet — strong enough for virtually any use case. For short-lived or low-risk tokens, 12–16 characters is often sufficient. For high-security tokens, 32+ is recommended.
Yes. Select the "Custom" preset and type any characters you want included. Duplicate characters are automatically removed. Note that smaller alphabets require longer IDs to maintain the same entropy level.
A Nano ID generator creates short, unique string identifiers optimized for modern software development. Unlike UUID (Universally Unique Identifier), Nano IDs are compact, highly configurable, and inherently URL-safe — making them the go-to choice for developers building APIs, databases, web apps, and microservices.
This free online Nano ID generator runs entirely in your browser. No data is sent to any server, and every ID is produced using your browser's cryptographically secure random number generator (crypto.getRandomValues()), ensuring true randomness.
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UUID (v4) is 36 characters long (with hyphens) and uses a fixed character set. Nano ID achieves equivalent collision resistance in just 21 characters using 64 symbols instead of 16. This makes Nano IDs:
Entropy is the measure of randomness in a generated ID. It determines how unlikely two randomly generated IDs are to collide (be identical). Entropy is calculated as:
entropy = length × log₂(alphabet_size)
For example, a 21-character ID with a 64-character alphabet gives 21 × log₂(64) = 21 × 6 = 126 bits of entropy. This is the same ballpark as UUID v4 (122 bits). A higher entropy means you could generate astronomically more IDs before expecting a single collision.
The alphabet you choose affects both the visual appearance and the safety of your IDs:
0, O, I, l.Nano IDs are widely used across modern software stacks:
example.com/share/V1StGXR8_Z5jdHi6B) are memorable and clean.With 126 bits of entropy (21-char URL-Safe Nano ID), you would need to generate approximately 2.8 × 10³⁷ IDs before expecting even a single collision. In practice, this means Nano IDs are collision-proof for any real-world application — even at millions of IDs per second, you'd run for longer than the age of the universe before hitting a duplicate.
If you reduce the length or use a smaller alphabet (like hex), the collision probability rises. This tool's entropy calculator helps you keep track of your safety margin.
If you want to generate Nano IDs programmatically in your codebase, the popular nanoid npm package (by Andrey Sitnik) is the go-to implementation for JavaScript/TypeScript. For other languages, there are official and community ports available for Python, Go, Rust, PHP, and more. This online tool is ideal for quickly generating IDs for testing, configuration, or one-off tasks without needing to set up a project.