layout | title | tagline | description |
---|---|---|---|
page |
ksqlDB HTTP API Reference |
Run queries over HTTP |
Learn how to communicate with ksqlDB by using HTTP |
- Introspect query status (/status endpoint)
- Introspect server status (/info endpoint)
- Execute a statement (/ksql endpoint)
- Run a query (/query endpoint)
- Run push and pull queries (/query-stream endpoint)
- Terminate a cluster (/ksql/terminate endpoint)
The default HTTP API endpoint is http://0.0.0.0:8088/
.
Change the server configuration that controls the HTTP API endpoint by
setting the listeners
parameter in the ksqlDB server config file. For
more info, see listeners.
To configure the endpoint to use HTTPS, see
Configure ksqlDB for HTTPS.
The ksqlDB HTTP API uses content types for requests and responses to indicate the serialization format of the data and the API version.
Your request should specify this serialization
format and version in the Accept
header, for example:
Accept: application/vnd.ksql.v1+json
The less specific application/json
content type is also permitted.
However, this is only for compatibility and ease of use, and you should
use the versioned value where possible. application/json
maps to the latest
versioned content type, meaning the response may change after upgrading the server to
a later version.
The server also supports content negotiation, so you may include multiple, weighted preferences:
Accept: application/vnd.ksql.v1+json; q=0.9, application/json; q=0.5
For example, content negotiation is useful when a new version of the API is preferred, but you are not sure if it is available yet.
Here's an example request that returns the results from the
LIST STREAMS
command:
curl -X "POST" "http://localhost:8088/ksql" \
-H "Accept: application/vnd.ksql.v1+json" \
-d $'{
"ksql": "LIST STREAMS;",
"streamsProperties": {}
}'
Here's an example request that retrieves streaming data from
TEST_STREAM
:
curl -X "POST" "http://localhost:8088/query" \
-H "Accept: application/vnd.ksql.v1+json" \
-d $'{
"sql": "SELECT * FROM TEST_STREAM EMIT CHANGES;",
"streamsProperties": {}
}'
Provide the --basic
and --user
options if basic HTTPS authentication is
enabled on the cluster, as shown in the following command.
curl -X "POST" "https://localhost:8088/ksql" \
-H "Accept: application/vnd.ksql.v1+json" \
--basic --user "<API key>:<secret>" \
-d $'{
"ksql": "LIST STREAMS;",
"streamsProperties": {}
}'
All API endpoints use a standard error message format for any requests that return an HTTP status indicating an error (any 4xx or 5xx statuses):
HTTP/1.1 <Error Status>
Content-Type: application/json
{
"error_code": <Error code>
"message": <Error Message>
}
Some endpoints may include additional fields that provide more context for handling the error.