---
title: "toObjectId"
description: "Converts String to org.bson.types.ObjectId."
---

# toObjectId

> Converts String to org.bson.types.ObjectId.

**This function is used by Ignition's Expression language.**

## Description
## Syntax
`toObjectId(stringId)`

| Type | Parameter | Description |
|---|---|---|
| String | `stringId` | A unique, 24 character string identifier that matches with an id of an existing document of a collection. |

### Results
**ObjectId** - A unique, 12 byte identifier that matches with an id of an existing document of a collection in both value and data type.

## Example
```py title="Code Snippet"
// In a Perspective MongoDB Binding, the expression below is applied to “value” of
// filter { _id: “value” }
 
toObjectId("5553a998e4b02cf7151190b8") // binding will return entire document of the matching _id
```