ashid

Time-sortable unique identifiers with type prefixes.

ashid("user_")  →  user_1kbg1jmtt4v3x8k9p2m1n
ashid("tx_")    →  tx_1kbg1jmts7h2w5r8q4n3m
ashid()         →  1kbg1jmtr9k5v2x8p4m1n3w

Installation

npm install ashid

import { ashid } from 'ashid';

const userId = ashid('user_');   // "user_1kbg1jmtt4v3x8k9p2m1n"
const shortId = ashid('u');      // "u1kbg1jmtt4v3x8k9p2m1n0w"
const rawId = ashid();           // "1kbg1jmtt4v3x8k9p2m1n0w"

Why ashid?

The Problem

UUIDs are opaque. When you see 550e8400-e29b-41d4-a716-446655440000 in a log, a URL, or a database query, you have no idea what it represents. Is it a user? A transaction? An asset? You have to grep, cross-reference, and waste debugging time.

The Solution

ashid generates IDs that tell you what they are:

user_1kbg1jmtt4v3x8k9p2m1n  // ← Obviously a user
tx_1kbg1jmts7h2w5r8q4n3m    // ← Obviously a transaction
asset_1kbg1jmtr9k5v2x8p4m1n // ← Obviously an asset

Why Crockford Base32?

Douglas Crockford designed Base32 specifically for human-readable identifiers:

• Case-insensitive — ABC and abc decode identically
• Character correction — I, L, l → 1 and O, o → 0 (no more "is that a zero or an O?")
• No ambiguous characters — excludes I, L, O, U entirely
• Double-click selectable — no hyphens or special characters
• URL-safe — no encoding required

This is the same approach Stripe uses for their IDs (sk_live_..., pi_..., cus_...).

Time-Sorted by Default

ashid embeds a timestamp, so lexicographic sort = chronological sort. Your database indexes cluster naturally. Your logs are in order. No extra work required.

Prefix Formats

ashid supports two formats based on prefix style:

With underscore delimiter (variable length)

ashid('user_')   // user_1kbg1jmtt4v3x8k9p2m1n
ashid('order_')  // order_1kbg1jmts7h2w5r8q4n3m

• Timestamp: variable length (no padding)
• Random: 13 chars (padded)
• Underscore acts as delimiter for reliable parsing

Without underscore (fixed 22-char base)

ashid('u')   // u1kbg1jmtt4v3x8k9p2m1n0w (1 + 22 = 23 chars)
ashid()      // 1kbg1jmtt4v3x8k9p2m1n0w  (22 chars)

• Timestamp: 9 chars (zero-padded)
• Random: 13 chars (padded)
• Fixed length enables parsing without delimiter

API Reference

ashid(prefix?: string): string

Generate a new ID with optional prefix.

import { ashid } from 'ashid';

ashid();          // "1kbg1jmtt4v3x8k9p2m1n0w"
ashid('u');       // "u1kbg1jmtt4v3x8k9p2m1n0w"
ashid('user_');   // "user_1kbg1jmtt4v3x8k9p2m1n"

Ashid.create(prefix?, time?, randomLong?): string

Create an ID with explicit timestamp and random values (useful for testing).

import { Ashid } from 'ashid';

Ashid.create('user_', 1733140800000, 8234567890123n);

parseAshid(id: string): [string, string, string]

Parse an ID into components: [prefix, encodedTimestamp, encodedRandom].

import { parseAshid } from 'ashid';

const [prefix, ts, rand] = parseAshid('user_1kbg1jmtt4v3x8k9p2m1n');
// prefix = "user_"
// ts = "1kbg1jmtt"
// rand = "4v3x8k9p2m1n"

Ashid.prefix(id: string): string

Extract the prefix from an ID.

Ashid.prefix('user_1kbg1jmtt4v3x8k9p2m1n');  // "user_"
Ashid.prefix('1kbg1jmtt4v3x8k9p2m1n0w');     // ""

Ashid.timestamp(id: string): number

Extract the timestamp (milliseconds since epoch).

Ashid.timestamp('user_1kbg1jmtt4v3x8k9p2m1n');  // 1733140800000

Ashid.random(id: string): bigint

Extract the random portion.

Ashid.random('user_1kbg1jmtt4v3x8k9p2m1n');  // 8234567890123n

Ashid.isValid(id: string): boolean

Validate an ID.

Ashid.isValid('user_1kbg1jmtt4v3x8k9p2m1n');  // true
Ashid.isValid('invalid');                      // false

Ashid.normalize(id: string): string

Normalize an ID (lowercase + fix ambiguous characters).

Ashid.normalize('USER_1KBG1JMTT4V3X8K9P2M1N');  // "user_1kbg1jmtt4v3x8k9p2m1n"
Ashid.normalize('user_IKBGIJMTT...');           // "user_1kbg1jmtt..." (I→1)

Format

[prefix][timestamp][random]
   ↓        ↓         ↓
 user_  1kbg1jmtt  4v3x8k9p2m1n

Prefix:    Letters + optional underscore (user defined)
Timestamp: Variable or 9 chars Crockford Base32 (milliseconds since epoch)
Random:    13 chars Crockford Base32 (cryptographically secure)

Timestamp range: 0 (Unix epoch) to 35184372088831 (Dec 12, 3084)

Crockford Base32 Encoding

The encoding excludes ambiguous characters and maps lookalikes during decoding:

| If you type | Decodes as | |-------------|------------| | I, i, L, l | 1 | | O, o | 0 | | U, u | v |

Read IDs aloud without confusion. Type without shift key. Copy without encoding errors.

Real-World Use Cases

API Resources

const userId = ashid('user_');     // user_1kbg1jmtt4v3x8k9p2m1n
const orderId = ashid('order_');   // order_1kbg1jmts7h2w5r8q4n3m
const invoiceId = ashid('inv_');   // inv_1kbg1jmtr9k5v2x8p4m1n

Database Primary Keys

// IDs sort chronologically without additional indexes
const posts = await db.query('SELECT * FROM posts ORDER BY id');

Log Debugging

[ERROR] Payment failed for user_1kbg1jmtt4v3x8k9p2m1n on order_1kbg1jmts7h2w5r8q4n3m
// Instantly know: it's a user and an order. No grepping required.

URL Slugs

https://app.example.com/users/user_1kbg1jmtt4v3x8k9p2m1n
https://app.example.com/orders/order_1kbg1jmts7h2w5r8q4n3m
// Self-documenting URLs that are still opaque enough for security

How ashid Compares

| Feature | ashid | uuid | nanoid | cuid2 | ulid | |---------|-------|------|--------|-------|------| | Type prefixes | ✅ Built-in | ❌ | ❌ | ❌ | ❌ | | Time-sortable | ✅ | ❌ | ❌ | ❌ | ✅ | | Human-readable | ✅ Crockford Base32 | ❌ Hex | ⚠️ Base64 | ⚠️ | ⚠️ | | Case-insensitive | ✅ | ✅ | ❌ | ✅ | ❌ | | Character correction | ✅ I→1, O→0 | ❌ | ❌ | ❌ | ❌ | | Double-click selectable | ✅ | ❌ Hyphens | ✅ | ✅ | ✅ | | URL-safe | ✅ | ⚠️ Needs encoding | ✅ | ✅ | ✅ | | Zero dependencies | ✅ | ✅ | ✅ | ✅ | ✅ | | Self-documenting in logs | ✅ | ❌ | ❌ | ❌ | ❌ |

The key difference: When you see user_1kbg1jmtt4v3x8k9p2m1n in a log, you know it's a user. When you see 550e8400-e29b-41d4-a716-446655440000, you have to grep.

Inspired By

ashid stands on the shoulders of giants:

• Stripe's ID format — The sk_, pi_, cus_ prefix convention
• Douglas Crockford's Base32 — Human-friendly encoding
• ULID — Time-sortable unique identifiers
• TypeID — Type-safe, K-sortable IDs (similar goals, different implementation)

Contributing

Contributions are welcome! Please see CONTRIBUTING.md for guidelines.

License

MIT

Author

Created by Dathan Guiley at Wilde Agency.

Built by Wilde Agency