> ## Documentation Index
> Fetch the complete documentation index at: https://upstash-vector.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# Publish
You can run the async code by importing `Client` from `upstash_qstash.asyncio`
and awaiting the methods.
#### Publish to a URL with a 3 second delay and headers/body
```python
from upstash_qstash import Client
client = Client("")
res = client.publish_json({
"url": "https://my-api...",
"body": { "hello": "world" },
"headers": { "test-header": "test-value" },
"delay": 3
})
print(res["messageId"])
```
#### Publish to a topic with a 3 second delay and headers/body
You can make a topic on the QStash console or using the [topics API](/qstash/sdks/py/examples/topics)
```python
from upstash_qstash import Client
client = Client("")
res = client.publish_json({
"topic": "mytopic",
"body": { "hello": "world" },
"headers": { "test-header": "test-value" },
"delay": 3
})
# When publishing to a topic, the response is an array of messages for each URL in the topic
print(res[0]["messageId"])
```
#### Publish a method with a callback URL
[Callbacks](/qstash/features/callbacks) are useful for long running functions. Here, QStash will return the response
of the publish request to the callback URL.
We also change the `method` to `GET` in this use case so QStash will make a `GET` request to the `url`. The default
is `POST`.
```python
from upstash_qstash import Client
client = Client("")
client.publish_json({
"url": "https://my-api...",
"body": { "hello": "world" },
"callback": "https://my-callback...",
"failure_callback": "https://my-failure-callback...",
"method": "GET"
})
```
#### Configure the number of retries
The max number of retries is based on your [QStash plan](https://upstash.com/pricing/qstash)
```python
from upstash_qstash import Client
client = Client("")
client.publish_json({
"url": "https://my-api...",
"body": { "hello": "world" },
"retries": 1
})
```
#### Publish HTML content instead of JSON
```python
from upstash_qstash import Client
client = Client("")
client.publish({
"url": "https://my-api...",
"body": "Hello World
",
"headers": {
"Content-Type": "text/html"
}
})
```
#### Publish a message with [content-based-deduplication](/qstash/features/deduplication)
```python
from upstash_qstash import Client
client = Client("")
client.publish_json({
"url": "https://my-api...",
"body": { "hello": "world" },
"content_based_deduplication": True
})
```