---
title: toIso8601DateTime
description: |
  Returns a timestamp formatted as an ISO 8601 string (e.g. `2023-08-11T07:29:17.634Z`).
  This function supports nanosecond precision.
url: https://coralogix.com/docs/dataprime/language-reference/functions-reference/time/toiso8601datetime/
product: dataengine
feature: DataPrime Language
feature_id: dataprime-language
feature_identifier: dataengine/dataprime-language
last_updated: '2026-10-21'
---

# `toIso8601DateTime`

Warning

`toIso8601DateTime` is deprecated.

<!-- -->

<!-- -->

Use [\`formatTimestamp\`](https://coralogix.com/docs/dataprime/language-reference/functions-reference/time/formattimestamp.md) instead.

## Description

Returns a timestamp formatted as an ISO 8601 string (e.g. `2023-08-11T07:29:17.634Z`). This function supports nanosecond precision.

## Syntax

Like many functions in DataPrime, `toIso8601DateTime` supports<!-- --> [two notations](https://coralogix.com/docs/dataprime/language-reference/functions-reference.md),<!-- --> **function** and **method**. These interchangeable forms allow flexibility in how you structure expressions.

* Function notation
* Method notation

```
toIso8601DateTime(timestamp: timestamp): string
```

```
(timestamp: timestamp).toIso8601DateTime(): string
```

## Arguments

| Name        | Type        | Required | Description                         |
| ----------- | ----------- | -------- | ----------------------------------- |
| `timestamp` | `timestamp` | **true** | The timestamp to format in ISO 8601 |

## Example

**Use case: Convert a timestamp into ISO 8601 format**

### Example query

* Function notation
* Method notation

```
create formatted_ts from toIso8601DateTime($m.timestamp)
```

```
create formatted_ts from $m.timestamp.toIso8601DateTime()
```

### Example output

```
{

  "formatted_ts": "2023-08-11T07:29:17.634Z"

}
```