docs-v2/content/v2.0/reference/line-protocol.md

---
title: Line protocol reference
description: >
  InfluxDB uses line protocol to write data points.
  It is a text-based format that provides the measurement, tag set, field set, and timestamp of a data point.
menu:
  v2_0_ref:
    name: Line protocol
weight: 6
v2.0/tags: [write, line protocol]
---

InfluxDB uses line protocol to write data points.
It is a text-based format that provides the measurement, tag set, field set, and timestamp of a data point.

- [Elements of line protocol](#elements-of-line-protocol)
- [Data types and format](#data-types-and-format)
- [Quotes](#quotes)
- [Special characters](#special-characters)
- [Comments](#comments)
- [Naming restrictions](#naming-restrictions)
- [Duplicate points](#duplicate-points)

```js
// Syntax
<measurement>[,<tag_key>=<tag_value>[,<tag_key>=<tag_value>]] <field_key>=<field_value>[,<field_key>=<field_value>] [<timestamp>]

// Example
myMeasurement,tag1=value1,tag2=value2 fieldKey="fieldValue" 1556813561098000000
```

Lines separated by the newline character `\n` represent a single point
in InfluxDB. Line protocol is whitespace sensitive.

{{% note %}}
Line protocol does not support the newline character `\n` in tag or field values.
{{% /note %}}

## Elements of line protocol

```
measurementName,tagKey=tagValue fieldKey="fieldValue" 1465839830100400200
--------------- --------------- --------------------- -------------------
       |               |                  |                    |
  Measurement       Tag set           Field set            Timestamp
```

### Measurement
<span class="required">Required</span> –
The measurement name.
InfluxDB accepts one measurement per point.
_Measurement names are case-sensitive and subject to [naming restrictions](#naming-restrictions)._

_**Data type:** [String](#string)_


### Tag set
_**Optional**_ –
All tag key-value pairs for the point.
Key-value relationships are denoted with the `=` operand.
Multiple tag key-value pairs are comma-delimited.
_Tag keys and tag values are case-sensitive.
Tag keys are subject to [naming restrictions](#naming-restrictions)._

_**Key data type:** [String](#string)_  
_**Value data type:** [String](#string)_

_See [naming restrictions](#naming-restrictions)_

### Field set
<span class="required">Required</span> –
All field key-value pairs for the point.
Points must have at least one field.
_Field keys and string values are case-sensitive.
Field keys are subject to [naming restrictions](#naming-restrictions)._

_**Key data type:** [String](#string)_  
_**Value data type:** [Float](#float) | [Integer](#integer) | [String](#string) | [Boolean](#boolean)_

_See [naming restrictions](#naming-restrictions)_

{{% note %}}
_Always double quote string field values. More on quotes [below](#quotes)._

```sh
measurementName fieldKey="field string value" 1556813561098000000
```
{{% /note %}}

### Timestamp
_**Optional**_ –
The Unix nanosecond timestamp for the data point.
InfluxDB accepts one timestamp per point.
If no timestamp is provided, InfluxDB uses the system time (UTC) of its host machine.

_**Data type:** [Unix timestamp](#unix-timestamp)_

{{% note %}}
Though timestamps are optional, include them to ensure times associated with points
are the actual times metrics were observed rather than when InfluxDB received them.
{{% /note %}}

{{% note %}}
_Use the default nanosecond precision timestamp or specify an alternative precision
when [writing the data](/v2.0/write-data/#precision)._
{{% /note %}}

### Whitespace
Whitespace in line protocol determines how InfluxDB interprets the data point.
The **first unescaped space** delimits the measurement and the tag set from the field set.
The **second unescaped space** delimits the field set from the timestamp.

```
measurementName,tagKey=tagValue fieldKey="fieldValue" 1465839830100400200
                               ┬                     ┬
                           1st space             2nd space
```

## Data types and format

### Float
IEEE-754 64-bit floating-point numbers.
Default numerical type.
_InfluxDB supports scientific notation in float field values._

##### Float field value examples
```js
myMeasurement fieldKey=1.0
myMeasurement fieldKey=1
myMeasurement fieldKey=-1.234456e+78
```

### Integer
Signed 64-bit integers.
Trailing `i` on the number specifies an integer.

| Minimum integer         | Maximum integer        |
| ---------------         | ---------------        |
| `-9223372036854775808i` | `9223372036854775807i` |

##### Integer field value examples
```js
myMeasurement fieldKey=1i
myMeasurement fieldKey=12485903i
myMeasurement fieldKey=-12485903i
```

### String
Plain text string.
Length limit 64KB.

##### String example
```sh
# String measurement name, field key, and field value
myMeasurement fieldKey="this is a string"
```

### Boolean
Stores `true` or `false` values.

| Boolean value | Accepted syntax                     |
|:-------------:|:---------------                     |
| True          | `t`, `T`, `true`, `True`, `TRUE`    |
| False         | `f`, `F`, `false`, `False`, `FALSE` |

##### Boolean field value examples
```js
myMeasurement fieldKey=true
myMeasurement fieldKey=false
myMeasurement fieldKey=t
myMeasurement fieldKey=f
myMeasurement fieldKey=TRUE
myMeasurement fieldKey=FALSE
```

{{% note %}}
Do not quote boolean field values.
Quoted field values are interpreted as strings.
{{% /note %}}

### Unix timestamp
Unix nanosecond timestamp.

| Minimum timestamp      | Maximum timestamp     |
| -----------------      | -----------------     |
| `-9223372036854775806` | `9223372036854775806` |

##### Unix timestamp example
```js
myMeasurementName fieldKey="fieldValue" 1556813561098000000
```

## Quotes
Line protocol supports single and double quotes as described in the following table:

| Element     | Double quotes                           | Single quotes                           |
| :------     | :------------:                          |:-------------:                          |
| Measurement | _Limited_ <sup class="required">*</sup> | _Limited_ <sup class="required">*</sup> |
| Tag key     | _Limited_ <sup class="required">*</sup> | _Limited_ <sup class="required">*</sup> |
| Tag value   | _Limited_ <sup class="required">*</sup> | _Limited_ <sup class="required">*</sup> |
| Field key   | _Limited_ <sup class="required">*</sup> | _Limited_ <sup class="required">*</sup> |
| Field value | **Strings only**                        | Never                                   |
| Timestamp   | Never                                   | Never                                   |

<sup class="required">\*</sup> _Line protocol accepts double and single quotes in
measurement names, tag keys, tag values, and field keys, but interprets them as
part of the name, key, or value._

## Special Characters
Line protocol supports special characters in [string elements](#string).
In the following contexts, it requires escaping certain characters with a backslash (`\`):

| Element     | Escape characters         |
|:-------     |:-----------------         |
| Measurement | Comma, Space              |
| Tag key     | Comma, Equals Sign, Space |
| Tag value   | Comma, Equals Sign, Space |
| Field key   | Comma, Equals Sign, Space |
| Field value | Double quote, Backslash   |

You do not need to escape other special characters.

##### Examples of special characters in line protocol
```sh
# Measurement name with spaces
my\ Measurement fieldKey="string value"

# Double quotes in a string field value
myMeasurement fieldKey="\"string\" within a string"

# Tag keys and values with spaces
myMeasurement,tag\ Key1=tag\ Value1,tag\ Key2=tag\ Value2 fieldKey=100

# Emojis
myMeasurement,tagKey=🍭 fieldKey="Launch 🚀" 1556813561098000000
```

### Escaping backslashes
Line protocol supports both literal backslashes and backslashes as an escape character.
With two contiguous backslashes, the first is interpreted as an escape character.
For example:

| Backslashes | Interpreted as |
|:-----------:|:-------------:|
| `\`         | `\`           |
| `\\`        | `\`           |
| `\\\`       | `\\`          |
| `\\\\`      | `\\`          |
| `\\\\\`     | `\\\`         |
| `\\\\\\`    | `\\\`         |

## Comments
Line protocol interprets `#` at the beginning of a line as a comment character
and ignores all subsequent characters until the next newline `\n`.

```sh
# This is a comment
myMeasurement fieldKey="string value" 1556813561098000000
```

## Naming restrictions
Measurement names, tag keys, and field keys cannot begin with an underscore `_`.
The `_` namespace is reserved for InfluxDB system use.

## Duplicate points
A point is uniquely identified by the measurement name, tag set, and timestamp.
If you submit line protocol with the same measurement, tag set, and timestamp,
but with a different field set, the field set becomes the union of the old
field set and the new field set, where any conflicts favor the new field set.