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ULID Generator

Generate ULIDs (Universally Unique Lexicographically Sortable Identifiers) with decoded timestamps, batch output, and monotonic mode.

import CopyButton from "./_CopyButton.astro"
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How to use ULID Generator

  1. Set the number of ULIDs you want to generate (1-100).
  2. Optionally enable Monotonic mode for strictly increasing IDs or Show Timestamp to see the decoded time.
  3. Click Generate, then use Copy to copy individual IDs or Copy All to grab everything.

What is ULID Generator?

ULID is a 26-character identifier that is lexicographically sortable by creation time. Each ULID encodes a 48-bit millisecond Unix timestamp followed by 80 bits of cryptographic randomness, encoded in Crockford's Base32 alphabet.

This tool generates ULIDs entirely in your browser using crypto.getRandomValues. You can create single or batch ULIDs (up to 100), view the decoded ISO timestamp for each one, and enable monotonic mode to guarantee strictly increasing IDs even within the same millisecond.

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FAQ

What is a ULID?
ULID stands for Universally Unique Lexicographically Sortable Identifier. It is a 26-character string that embeds a millisecond timestamp, making IDs naturally sortable by creation time.
How does monotonic mode work?
When enabled, if two ULIDs would share the same millisecond timestamp, the random component is incremented to guarantee strict ordering. This prevents duplicates even under high-frequency generation.
Are the ULIDs cryptographically random?
Yes. The 80-bit random component uses crypto.getRandomValues, which provides cryptographically strong randomness in all modern browsers.

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