# MongoDB ObjectId Generator

> MongoDB ID generator for 12-byte ObjectIds. Create one ID or a batch, copy the values, and read the timestamp embedded in each ObjectId.

- **Source:** DevDreaming (https://devdreaming.com)
- **Canonical URL:** https://devdreaming.com/tools/mongodb-objectid-generator
- **Category:** Database & Backend
- **Price:** Free - no signup

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## What this tool does

The MongoDB ObjectId Generator, also called a MongoDB ID generator, creates 24-character hexadecimal IDs and shows the timestamp embedded in each one. Generate one ID or a batch using the current time or a custom date.

A standard MongoDB ObjectId contains a 4-byte Unix timestamp, a 5-byte random value, and a 3-byte counter. This browser tool puts the chosen timestamp first and fills the remaining bytes with generated hexadecimal values, then decodes the timestamp into a readable date. It is useful for sample data; MongoDB's driver should create production IDs.

Everything runs in your browser with no signup. The generated IDs never leave your machine, which makes the tool convenient for seeding test data and fixtures.

## How to use it

1. Set the Number of IDs field to how many ObjectIds you want, between 1 and 100.
2. Leave Use current timestamp checked to stamp each ID with the current time.
3. To backdate the IDs, uncheck that box and pick a date and time in the Custom Timestamp field.
4. Click Generate ObjectID to produce the IDs.
5. Review each generated ID along with the creation date decoded from its embedded timestamp.
6. Use the copy icon on any ID, click Copy All to grab the whole batch, or press Ctrl+L to clear.

**[Open the MongoDB ObjectId Generator tool ->](https://devdreaming.com/tools/mongodb-objectid-generator)**

This tool runs in your browser and cannot be operated from this Markdown copy - open the link above to use it.

## What you can use it for

- Creating sample _id values for development or test fixtures.
- Creating placeholder ObjectIds for API mocks and integration tests before real data exists.
- Generating ObjectIds with a backdated timestamp to test time-based sorting or queries.
- Producing a batch of IDs to populate sample documents or demo datasets.
- Inspecting how the timestamp is encoded in the first eight hex characters of an ObjectId.
- Getting a valid 24-character ObjectId quickly without opening a Mongo shell or driver.

## Key features

- Generates 24-character hexadecimal strings in the 12-byte ObjectId layout.
- Batch generation of up to 100 IDs at once.
- Optional custom timestamp so IDs can be dated to any moment.
- Decodes and displays the creation date stored in each ID's first four bytes.
- Copy a single ID or copy the whole batch with one click.

## Frequently asked questions

### What is a MongoDB ObjectId?

A MongoDB ObjectId is a 12-byte identifier, shown as 24 hexadecimal characters, used as the default _id for documents. Standard ObjectIds contain a 4-byte timestamp, a 5-byte random value, and a 3-byte counter.

### How does the MongoDB ObjectId generator work?

It writes the chosen Unix timestamp in seconds into the first four bytes, then generates hexadecimal values for the other eight bytes. It also decodes the first four bytes to show the date. This tool does not maintain MongoDB's usual incrementing counter.

### Are the generated ObjectIds valid for use in MongoDB?

The tool produces 24-character hexadecimal strings that can be parsed as ObjectIds. Its generated bytes are intended for sample data, and collisions are possible. Let a MongoDB driver generate IDs for production records.

### Can I generate an ObjectId for a specific date?

Yes. Uncheck Use current timestamp and pick a date and time in the Custom Timestamp field. The generator encodes that moment into the timestamp portion of every ID in the batch.

### How do I extract the timestamp from an ObjectId?

The first eight hexadecimal characters of an ObjectId are the creation time in seconds since the Unix epoch. This tool decodes that value automatically and shows the creation date next to each generated ID.

### Is the ObjectId generator free and private?

Yes. The generator is free, needs no signup, and runs entirely in your browser. The IDs are created locally with JavaScript and are never sent to a server.

## Privacy

All tools on DevDreaming run entirely in your browser - your input is never uploaded to a server.

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