AIOHTTPTransport¶

This transport uses the aiohttp library and allows you to send GraphQL queries using the HTTP protocol.

Reference: gql.transport.aiohttp.AIOHTTPTransport

This transport supports both standard GraphQL operations (queries, mutations) and subscriptions. Subscriptions are implemented using the multipart subscription protocol as implemented by Apollo GraphOS Router and other compatible servers.

This provides an HTTP-based alternative to WebSocket transports for receiving streaming subscription updates. It’s particularly useful when:

WebSocket connections are not available or blocked by infrastructure
You want to use standard HTTP with existing load balancers and proxies
The backend implements the multipart subscription protocol

Queries¶

import asyncio

from gql import Client, gql
from gql.transport.aiohttp import AIOHTTPTransport


async def main():

    # Select your transport with a defined url endpoint
    transport = AIOHTTPTransport(url="https://countries.trevorblades.com/graphql")

    # Create a GraphQL client using the defined transport
    client = Client(transport=transport)

    # Provide a GraphQL query
    query = gql(
        """
        query getContinents {
          continents {
            code
            name
          }
        }
    """
    )

    # Using `async with` on the client will start a connection on the transport
    # and provide a `session` variable to execute queries on this connection
    async with client as session:

        # Execute the query
        result = await session.execute(query)
        print(result)


asyncio.run(main())

Subscriptions¶

The transport sends a standard HTTP POST request with an Accept header indicating support for multipart responses:

Accept: multipart/mixed;subscriptionSpec="1.0", application/json

The server responds with a multipart/mixed content type and streams subscription updates as separate parts in the response body. Each part contains a JSON payload with GraphQL execution results.

import asyncio
import logging

from gql import Client, gql
from gql.transport.aiohttp import AIOHTTPTransport

logging.basicConfig(level=logging.INFO)


async def main():

    transport = AIOHTTPTransport(url="https://gql-book-server.fly.dev/graphql")

    # Using `async with` on the client will start a connection on the transport
    # and provide a `session` variable to execute queries on this connection
    async with Client(
        transport=transport,
    ) as session:

        # Request subscription
        subscription = gql(
            """
            subscription {
              book {
                title
                author
              }
            }
        """
        )

        # Subscribe and receive streaming updates
        async for result in session.subscribe(subscription):
            print(f"Received: {result}")


asyncio.run(main())

How It Works¶

Message Format

Each message part follows this structure:

--graphql
Content-Type: application/json

{"payload": {"data": {...}, "errors": [...]}}

Heartbeats

Servers may send empty JSON objects ({}) as heartbeat messages to keep the connection alive. These are automatically filtered out by the transport.

Error Handling

The protocol distinguishes between two types of errors:

GraphQL errors: Returned within the payload property alongside data
Transport errors: Returned with a top-level errors field and null payload

End of Stream

The subscription ends when the server sends the final boundary marker:

--graphql--

Limitations¶

Subscriptions require the server to implement the multipart subscription protocol
Long-lived connections may be terminated by intermediate proxies or load balancers
Some server configurations may not support HTTP/1.1 chunked transfer encoding required for streaming

Authentication¶

There are multiple ways to authenticate depending on the server configuration.

Using HTTP Headers

transport = AIOHTTPTransport(
    url='https://SERVER_URL:SERVER_PORT/graphql',
    headers={'Authorization': 'token'}
)

Using HTTP Cookies

You can manually set the cookies which will be sent with each connection:

transport = AIOHTTPTransport(url=url, cookies={"cookie1": "val1"})

Or you can use a cookie jar to save cookies set from the backend and reuse them later.

In some cases, the server will set some connection cookies after a successful login mutation and you can save these cookies in a cookie jar to reuse them in a following connection (See issue 197):

jar = aiohttp.CookieJar()
transport = AIOHTTPTransport(url=url, client_session_args={'cookie_jar': jar})