Free ID Generator Online - Generate Unique Identifiers
Generate unique identifiers: Nano ID (URL-safe), Short ID, and custom format IDs. Cryptographically secure, bulk generation up to 5000 IDs.
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Key Features
⚡ Fast Processing
Generate unique IDs instantly using cryptographically secure random values.
🔒 Privacy Protected
All ID generation happens locally in your browser. No data is transmitted.
How to Use ID Generator
Select ID Type
Choose Nano ID, Short ID, or Custom character set using the tabs.
Configure and Generate
Set length and count, then click "Generate" to create unique identifiers.
Copy or Download
Copy IDs to clipboard or download as a text file.
Frequently Asked Questions
Basics
What is Nano ID?
Nano ID is a compact, URL-safe unique string ID generator, similar to UUID but much shorter (default 21 characters vs 36 for UUID). It uses cryptographically secure random values from the Web Crypto API and has a collision probability similar to UUID v4. Nano ID is ideal for database primary keys, API keys, session tokens, password reset links, and any use case requiring globally unique identifiers with minimal length. The default character set (A-Z a-z 0-9 _ -) contains no ambiguous characters and is safe for URLs, file names, and JSON.
How unique are these IDs?
The uniqueness depends on the selected length and character set size. With Nano ID (length 21, 64-character set), the probability of generating a duplicate after 1 billion IDs is astronomically low (less than 1 in a billion). For short IDs (e.g., length 8, 62-character set), the collision probability after 1 million IDs is approximately 0.01%. This ID generator includes a real-time collision probability estimator that shows the approximate chance of collision based on your current settings, helping you choose the optimal length for your use case.
What's the difference between Nano ID, Short ID, and Custom mode?
Nano ID is designed for maximum uniqueness with moderate length (default 21 chars) using a URL-safe character set (A-Za-z0-9_-), ideal for database keys and security tokens. Short ID is optimized for human readability and brevity (typically 6-12 chars), suitable for verification codes, invite links, or order numbers where a small collision chance is acceptable. Custom mode gives you full control over both character set and length, allowing you to create IDs matching specific system requirements like numeric OTPs, hex-style IDs, or base-36 encoding.
How do I generate multiple IDs at once?
Use the Count selector to choose how many IDs you want to generate (1 to 5000). After generating, you can copy individual IDs using the copy icon next to each ID, or copy all IDs at once using the main Copy button. The output format can be changed to comma-separated, JSON array, or SQL IN format using the output format dropdown. For large batches, use the Download button to save IDs as TXT, JSON, or CSV files for further processing.
Security & Technical Details
Are these IDs cryptographically secure?
Yes, this ID generator uses the Web Crypto API (`crypto.getRandomValues()`) as its random source. This provides cryptographically strong random values suitable for security-sensitive applications including session tokens, password reset links, API keys, and authentication tokens. All generation happens locally in your browser using JavaScript — no data is ever transmitted over the network or stored on any server, ensuring complete privacy and security.
What is the default character set and can I change it?
Nano ID uses the URL-safe character set containing 64 characters: uppercase A-Z, lowercase a-z, digits 0-9, underscore (_), and hyphen (-). Short ID uses alphanumeric characters (A-Za-z0-9) by default. In Custom mode, you can specify any ASCII character set you need — for example, `0123456789` for numeric-only IDs, `ABCDEF` for hex-style IDs, or `ABCDEFGHIJKLMNOPQRSTUVWXYZ` for uppercase-only IDs. The tool shows the character set size in real-time to help you understand the entropy of your generated IDs.
Nano ID vs UUID Comparison
| Feature | UUID v4 | Nano ID |
|---|---|---|
| Length | 36 characters | 21 characters (default) |
| Character Set | Hex + hyphens (0-9, a-f, -) | A-Z, a-z, 0-9, _, - |
| URL Safe | Yes (with hyphens) | Yes (fully safe) |
| Collision Probability | ~5.3×10^-36 | ~1×10^-9 (after 100M IDs) |
| Cryptographic Security | Yes | Yes |
| Human Readable | Moderate | Better (shorter) |
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