MongoDB ObjectId Generator

Generate valid 12-byte MongoDB ObjectIDs and parse their internal timestamp.

Number of IDs

Use current timestamp

65a7b3c04f2e9d8a1b3c→ 24 characters (12 bytes)

Bytes 0-3:Timestamp (seconds since Unix epoch)

Bytes 4-8:Random value (process ID + machine ID)

Bytes 9-11:Counter (incremental value)

•Default _id: MongoDB automatically generates ObjectIds for documents

•Unique: Globally unique across collections and databases

•Sortable: Contains timestamp, allowing chronological ordering

•12 bytes: More compact than UUIDs (16 bytes)

•Extracting time: First 8 hex chars = timestamp in seconds

•Node.js: Use new ObjectId() with mongodb driver

MongoDB ObjectIds are 12-byte identifiers composed of timestamp, random, and counter values.

First 4 bytes contain Unix timestamp in seconds - allows sorting by creation date.

Next 5 bytes are random machine/process identifier - ensures uniqueness across systems.

Last 3 bytes form an auto-incrementing counter - prevents collision within same millisecond.

ObjectIds are globally unique even without centralized coordination - perfect for distributed systems.

Commonly used as _id field in MongoDB documents - automatically generated if not specified.