Every MongoDB document’s default _id is a 24-character hex string that looks random, but it isn’t — it’s actually a structured 12-byte value that embeds the exact second it was created. This tool generates valid ObjectIds and, more usefully, decodes existing ones to reveal what’s hidden inside them.
What Is the MongoDB ObjectId Generator & Decoder?
Click “Generate” to produce a fresh, spec-compliant 12-byte ObjectId you can paste straight into a document or test fixture. Or paste any existing ObjectId into the decoder to see its embedded creation timestamp, the 5-byte random value unique to the generating machine/process, and the 3-byte incrementing counter — all broken out separately.
How to Use It
- Open the tool at /tools/mongodb-objectid-tool.
- Click “Generate” for a new, valid ObjectId, or paste an existing one into the decode box.
- Read off the exact creation timestamp, random value, and counter embedded in it.
- Copy the generated ObjectId for use in test data, fixtures, or manual queries.
Key Features
- Spec-compliant generation — every generated ObjectId follows MongoDB’s exact 12-byte timestamp/random/counter structure.
- Instant timestamp decoding — see precisely when any ObjectId was created, down to the second.
- No database connection required — everything runs client-side against the raw hex string.
- One-click copy of the generated ObjectId.
When to Use This Tool
- Building test fixtures or seed data that need realistic, valid MongoDB
_idvalues. - Investigating when a document was actually created just from its
_id, without querying the database. - Learning how MongoDB’s default ID scheme is structured under the hood.
Try It Now
Open MongoDB ObjectId Generator & Decoder directly, or press ⌘K and type the tool name from anywhere on the site.
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