Access EMQX Tables via HTTP API

EMQX Tables provides an HTTP API interface that allows users of Dedicated (legacy) and Serverless deployments to insert and query data directly through HTTP requests. This is useful for applications or scripts that prefer a simple HTTP integration rather than MQTT or SDK-based methods.

The HTTP API supports multiple protocols:

• SQL: Execute SQL statements for querying or inserting data.
• PromQL: Query data using Prometheus Query Language (PromQL).
• InfluxDB Line Protocol: Write data in the InfluxDB-compatible line format.

SQL over HTTP

Base URL

The HTTP API uses the Host address provided in the Connection Info section on the EMQX Tables Deployment Overview page.

It uses HTTPS protocol on port 443 (default, no need to specify).

Example:

https://k81a5888.ala.us-east-1.aws.emqxtables.com

All SQL-related requests are sent to the following endpoint:

<BASE_URL>/v1/sql

Example:

https://k81a5888.ala.us-east-1.aws.emqxtables.com/v1/sql

Required Headers

Requests to the EMQX Tables HTTP API require specific headers to handle authentication and data format. All examples below use HTTPS protocol.

Authentication

EMQX Tables HTTP API uses Basic Authentication.

Add the following header to your request:

Authorization: Basic <Base64(username:password)>

• Both the username and password can be found on the EMQX Tables Deployment Overview page, under the Connection Info section in the EMQX Cloud console.
• These credentials are unique for each deployment and required for all API access.

To create the Base64-encoded string:

1. Concatenate your username and password with a colon:

   username:password

2. Encode the result with Base64.

For example:

Username: k81a5888q2aa1077
Password: p11cb3e282a77af1

After Base64 encoding:

azgxYTU4ODhxMmFhMTA3NzpwMTFjYjNlMjgyYTc3YWYx

Your header becomes:

Authorization: Basic azgxYTU4ODhxMmFhMTA3NzpwMTFjYjNlMjgyYTc3YWYx

Other Headers

Header	Description	Example
Content-Type	The request body must be form-encoded.	Content-Type: application/x-www-form-urlencoded
X-Greptime-Timeout	(Optional) Sets the server-side query timeout.	X-Greptime-Timeout: 120s
X-Greptime-Timezone	(Optional) Sets the time zone for time-related SQL operations.	X-Greptime-Timezone: +1:00

Query Parameters

You can include optional query string parameters to control output format and database context.

Parameter	Description	Default	Notes
db	Specifies the target database name.	public	Optional
format	Specifies the output format.	greptimedb_v1	Optional. Controls response format. See below for all supported formats.

Supported formats:

• greptimedb_v1: Default JSON output.
• influxdb_v1: InfluxDB-compatible query response.
  • Additional parameter: epoch ([ns, u, µ, ms, s, m, h]) sets timestamp precision.
• csv: Outputs as comma-separated values without headers.
• csvWithNames: Outputs as comma-separated values with a column names header.
• csvWithNamesAndTypes: Outputs as comma-separated values with column names and data types headers.
• arrow: Apache Arrow IPC format
  • Additional parameter: compression (zstd or lz4), default: no compression.
• table: ASCII table output for console output.
• null: Concise text-only output of the row count and elapsed time, useful for evaluating query performance.

Execute SQL Statements

Use the POST method with application/x-www-form-urlencoded content type. This content type means the request body is encoded as simple key-value pairs:

• Key: sql
• Value: The SQL statement to execute

Example request body:

sql=SHOW TABLES

SQL Statements Examples

Example 1: List all tables

This example shows how to execute SHOW TABLES statement to list all the tables in public database.

Request

POST https://k81a5888.ala.us-east-1.aws.emqxtables.com/v1/sql
Content-Type: application/x-www-form-urlencoded
Authorization: Basic azgxYTU4ODhxMmFhMTA3NzpwMTFjYjNlMjgyYTc3YWYx

sql=SHOW TABLES

Response

{
  "output": [
    {
      "records": {
        "schema": {
          "column_schemas": [
            { "name": "Tables", "data_type": "String" }
          ]
        },
        "rows": [
          ["sensor_temperature_humidity"]
        ],
        "total_rows": 1
      }
    }
  ],
  "execution_time_ms": 4
}

Example 2: Insert a record

This example inserts a new data row into the sensor_temperature_humidity table using an INSERT INTO SQL statement.

Request

POST https://k81a5888.ala.us-east-1.aws.emqxtables.com/v1/sql
Content-Type: application/x-www-form-urlencoded
Authorization: Basic azgxYTU4ODhxMmFhMTA3NzpwMTFjYjNlMjgyYTc3YWYx

sql=INSERT INTO sensor_temperature_humidity(device_id, temperature, humidity, ts) VALUES ('sensors001', 42.0, 42.0, now())

Response

{
  "output": [
    { "affectedrows": 1 }
  ],
  "execution_time_ms": 2
}

Example 3: Query data (default JSON output)

This example queries all data from the sensor_temperature_humidity table and return the result in the default JSON format.

Request

POST https://k81a5888.ala.us-east-1.aws.emqxtables.com/v1/sql
Content-Type: application/x-www-form-urlencoded
Authorization: Basic azgxYTU4ODhxMmFhMTA3NzpwMTFjYjNlMjgyYTc3YWYx

sql=SELECT * FROM sensor_temperature_humidity

Response

{
  "output": [
    {
      "records": {
        "schema": {
          "column_schemas": [
            { "name": "device_id", "data_type": "String" },
            { "name": "temperature", "data_type": "Float64" },
            { "name": "humidity", "data_type": "Float64" },
            { "name": "ts", "data_type": "TimestampMillisecond" }
          ]
        },
        "rows": [
          ["sensors001", 42.0, 42.0, 1764150607785]
        ],
        "total_rows": 1,
        "metrics": { "greptime_cloud_rcu": 1 }
      }
    }
  ],
  "execution_time_ms": 3
}

Example 4: Query data (CSV output)

This example queries all data from the sensor_temperature_humidity table and return the result in CSV format.

Request

POST https://k81a5888.ala.us-east-1.aws.emqxtables.com/v1/sql?format=csv
Content-Type: application/x-www-form-urlencoded
Authorization: Basic azgxYTU4ODhxMmFhMTA3NzpwMTFjYjNlMjgyYTc3YWYx

sql=SELECT * FROM sensor_temperature_humidity

Response

sensors001,42.0,42.0,1764150607785

Notes

• Default database: All SQL queries operate on the public database unless db is specified in the query string.
• Timeouts: Long-running queries can be terminated early by setting X-Greptime-Timeout.
• Time zone: Use X-Greptime-Timezone to control how timestamps are interpreted and returned.
• Security: Always use HTTPS and never share your plain credentials.
• Response time: The execution_time_ms field indicates server-side query duration.

PromQL over HTTP

EMQX Tables supports querying time-series data using Prometheus Query Language (PromQL) through HTTP APIs.

Two types of PromQL-compatible APIs are available:

1. Prometheus-compatible APIs: Returns results in standard Prometheus response format.
2. GreptimeDB JSON output API: Returns results in GreptimeDB’s data-frame format, similar to SQL queries.

Both options support HTTPS and Basic Authentication.

Prometheus-Compatible PromQL APIs

Endpoints

EMQX Tables exposes Prometheus-compatible query APIs under /v1/prometheus/api/v1:

Operation	Endpoint
Instant query	/v1/prometheus/api/v1/query
Range query	/v1/prometheus/api/v1/query_range
Series	/v1/prometheus/api/v1/series
Label names	/v1/prometheus/api/v1/labels
Label values	/v1/prometheus/api/v1/label/<label_name>/values

All endpoints support both GET and POST.

Required Headers

Header	Description
Authorization	Same as SQL API: Authorization: Basic <Base64(username:password)>
Content-Type	Required only for POST requests: application/x-www-form-urlencoded

Query Parameters

Parameter	Description	Default
db	Database name	public

Additional query parameters follow the Prometheus specification:

• For GET requests: Pass query parameters as URL encoded strings. Refer to Prometheus documentation.
• For POST requests: Provide parameters using application/x-www-form-urlencoded body.

Request Body (POST)

For POST requests, include the PromQL parameters using form-encoded key-value pairs.

Example keys:

• query
• start
• end
• step

Example: Range Query (60-second step)

Query temperature values during a 10-minute period.

Request

POST https://k81a5888.ala.us-east-1.aws.emqxtables.com/v1/prometheus/api/v1/query_range
Authorization: Basic azgxYTU4ODhxMmFhMTA3NzpwMTFjYjNlMjgyYTc3YWYx
Content-Type: application/x-www-form-urlencoded

query=sensor_temperature
start=2025-11-28T10:00:00Z
end=2025-11-28T10:10:00Z
step=60s

Response (200 OK)

{
    "status": "success",
    "data": {
        "resultType": "matrix",
        "result": [
            {
                "metric": {
                    "__name__": "sensor_temperature",
                    "device_id": "sensor_1"
                },
                "values": [
                    [
                        1764324000.0,
                        "22.5"
                    ],
                    [
                        1764324060.0,
                        "22.600000381469727"
                    ],
                    [
                        1764324120.0,
                        "22.700000762939453"
                    ],
                    [
                        1764324180.0,
                        "22.799999237060547"
                    ],
                    [
                        1764324240.0,
                        "22.899999618530273"
                    ],
                    [
                        1764324300.0,
                        "23"
                    ],
                    [
                        1764324360.0,
                        "23.100000381469727"
                    ],
                    [
                        1764324420.0,
                        "23.200000762939453"
                    ],
                    [
                        1764324480.0,
                        "23.299999237060547"
                    ],
                    [
                        1764324540.0,
                        "23.399999618530273"
                    ],
                    [
                        1764324600.0,
                        "23.399999618530273"
                    ]
                ]
            }
        ]
    }
}

Example: Range Query with irate() (3-minute window)

Query the temperature increase rate over a time range, using a 3-minute calculation window and a 60-second step.

Request

POST https://k81a5888.ala.us-east-1.aws.emqxtables.com/v1/prometheus/api/v1/query_range
Authorization: Basic azgxYTU4ODhxMmFhMTA3NzpwMTFjYjNlMjgyYTc3YWYx
Content-Type: application/x-www-form-urlencoded

query=irate(sensor_temperature[3m])
start=2025-11-28T10:00:00Z
end=2025-11-28T10:10:00Z
step=60s

Response (200 OK)

{
    "status": "success",
    "data": {
        "resultType": "matrix",
        "result": [
            {
                "metric": {
                    "__name__": "sensor_temperature",
                    "device_id": "sensor_1"
                },
                "values": [
                    [
                        1764324060.0,
                        "0.0016666730244954428"
                    ],
                    [
                        1764324120.0,
                        "0.0016666730244954428"
                    ],
                    [
                        1764324180.0,
                        "0.0016666412353515624"
                    ],
                    [
                        1764324240.0,
                        "0.0016666730244954428"
                    ],
                    [
                        1764324300.0,
                        "0.0016666730244954428"
                    ],
                    [
                        1764324360.0,
                        "0.0016666730244954428"
                    ],
                    [
                        1764324420.0,
                        "0.0016666730244954428"
                    ],
                    [
                        1764324480.0,
                        "0.0016666412353515624"
                    ],
                    [
                        1764324540.0,
                        "0.0016666730244954428"
                    ],
                    [
                        1764324600.0,
                        "0.0016666730244954428"
                    ]
                ]
            }
        ]
    }
}

GreptimeDB JSON Format PromQL API

EMQX Tables also exposes an API that executes PromQL but returns results using the same data-frame JSON format as the SQL API.

Endpoint

GET /v1/promql

Required Headers

Header	Description
Authorization	Same as SQL API: Authorization: Basic <Base64(username:password)>

Query Parameters

Parameter	Description
db	Database name (default = public)
query	PromQL expression
start	Start time (rfc3339 or unix_timestamp)
end	End time (rfc3339 or unix_timestamp)
step	Resolution step, supports duration format or float seconds
format	Optional output format (same as SQL API formats)

Supported Timestamp Formats

Examples of valid start/end values:

RFC3339

• 2015-07-01T20:11:00Z (default to seconds resolution)
• 2015-07-01T20:11:00.781Z (with milliseconds resolution)
• 2015-07-02T04:11:00+08:00 (with timezone offset)

Unix timestamp

• 1435781460 (default to seconds resolution)
• 1435781460.781 (with milliseconds resolution)

Duration formats

• 1h (1 hour)
• 5d1m (5 days and 1 minute)
• 2 (2 seconds)
• 2s (also 2 seconds)

Example: irate() Query (GreptimeDB JSON Format)

Query the temperature increase rate over a time range, using a 3-minute calculation window and a 60-second step.

Request

GET https://k81a5888.ala.us-east-1.aws.emqxtables.com/v1/promql?query=irate(sensor_temperature[3m])&start=2025-11-28T10:00:00Z&end=2025-11-28T10:10:00Z&step=60s
Authorization: Basic azgxYTU4ODhxMmFhMTA3NzpwMTFjYjNlMjgyYTc3YWYx

Response (200 OK)

{
    "output": [
        {
            "records": {
                "schema": {
                    "column_schemas": [
                        {
                            "name": "ts",
                            "data_type": "TimestampMillisecond"
                        },
                        {
                            "name": "prom_irate(ts_range,temperature)",
                            "data_type": "Float64"
                        },
                        {
                            "name": "device_id",
                            "data_type": "String"
                        }
                    ]
                },
                "rows": [
                    [
                        1764324060000,
                        0.0016666730244954428,
                        "sensor_1"
                    ],
                    [
                        1764324120000,
                        0.0016666730244954428,
                        "sensor_1"
                    ],
                    [
                        1764324180000,
                        0.0016666412353515624,
                        "sensor_1"
                    ],
                    [
                        1764324240000,
                        0.0016666730244954428,
                        "sensor_1"
                    ],
                    [
                        1764324300000,
                        0.0016666730244954428,
                        "sensor_1"
                    ],
                    [
                        1764324360000,
                        0.0016666730244954428,
                        "sensor_1"
                    ],
                    [
                        1764324420000,
                        0.0016666730244954428,
                        "sensor_1"
                    ],
                    [
                        1764324480000,
                        0.0016666412353515624,
                        "sensor_1"
                    ],
                    [
                        1764324540000,
                        0.0016666730244954428,
                        "sensor_1"
                    ],
                    [
                        1764324600000,
                        0.0016666730244954428,
                        "sensor_1"
                    ]
                ],
                "total_rows": 10,
                "metrics": {
                    "greptime_cloud_rcu": 2
                }
            }
        }
    ],
    "execution_time_ms": 5
}

InfluxDB Line Protocol over HTTP

EMQX Tables supports ingesting time-series data using the InfluxDB Line Protocol, compatible with InfluxDB write APIs.

Endpoint

POST /v1/influxdb/api/v2/write

Query Parameters

Parameter	Description	Default
db	Target database	public
precision	Timestamp precision (ns, us, ms, s)	ns

Required Headers

Authorization

Unlike the SQL and PromQL APIs, the InfluxDB Line Protocol API uses a different authentication format:

Authorization: token <username:password>

For example, if the username is k81a5888q2aa1077 and the password is p11cb3e282a77af1, the header becomes:

Authorization: token k81a5888q2aa1077:p11cb3e282a77af1

Request Body

Send a raw string formatted according to the InfluxDB Line Protocol specification.

Example:

sensor_temperature_humidity,device_id="sensor001" temperature=42.0,humidity=42.0 1764295258644

Response

Status	Meaning
204 No Content	Write successful

No response body is returned.

Example

This example writes a single data point using InfluxDB Line Protocol.

Request

POST https://k81a5888.ala.us-east-1.aws.emqxtables.com/v1/influxdb/api/v2/write?precision=ms
Authorization: token k81a5888q2aa1077:p11cb3e282a77af1

sensor_temperature_humidity,device_id="sensor001" temperature=42.0,humidity=42.0 1764295258644

Response

204 No Content