> For the complete documentation index, see [llms.txt](https://docs.cartesi.io/llms.txt)

---
id: cartesi-rollup-http-api
title: "Cartesi Rollup HTTP API"
description: "API that the Cartesi Rollup HTTP Server implements."
sidebar_label: Introduction
sidebar_position: 0
hide_title: true
custom_edit_url: null
---

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import Heading from "@theme/Heading";
import SchemaTabs from "@theme/SchemaTabs";
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import Export from "@theme/ApiExplorer/Export";

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  className={"theme-doc-version-badge badge badge--secondary"}
  children={"Version: 0.5.1"}
>
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  as={"h1"}
  className={"openapi__heading"}
  children={"Cartesi Rollup HTTP API"}
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</Heading>



API that the Cartesi Rollup HTTP Server implements.

In the box below, there is an example of a dApp backend that uses the Rollup HTTP API.

```
import requests
import sys

rollup = sys.argv[1]

def check_status_code(response):
    if response.status_code not in range(200, 300):
        print(f'Error: invalid status code {response.status_code}')
        sys.exit(1)
    return response

finish = {'status': 'accept'}
while True:
    print('Sending finish')
    r = check_status_code(requests.post(rollup + '/finish', json=finish))
    if r.status_code == 202:
        print('No pending rollup request, trying again')
        continue

    rollup_request = r.json()
    if rollup_request['request_type'] == 'advance_state':
        print('Sending voucher')
        voucher = {
            'destination': rollup_request['data']['metadata']['msg_sender'],
            'payload': rollup_request['data']['payload']
        }
        check_status_code(requests.post(rollup + '/voucher', json=voucher))

        print('Sending notice')
        notice = {'payload': rollup_request['data']['payload']}
        check_status_code(requests.post(rollup + '/notice', json=notice))

        print('Sending report')
        report = {'payload': rollup_request['data']['payload']}
        check_status_code(requests.post(rollup + '/report', json=report))

        finish['status'] = 'accept'

    elif rollup_request['request_type'] == 'inspect_state':
        print('Sending report per inspect request')
        report = {'payload': rollup_request['data']['payload']}
        check_status_code(requests.post(rollup + '/report', json=report))

    else:
        print('Throwing rollup exception')
        exception = {'payload': rollup_request['data']['payload']}
        requests.post(rollup + '/exception', json=exception)
        break
```

In production mode, if the dApp exits the Rollups initialization script will register a Rollup Exception.
See [/exception](./register-exception).

In host mode, the Cartesi Rollups infrastructure is not able to detect that the dApp exited.
It is up to the dApp developer to re-launch the dApp.


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  <h3
    style={{"marginBottom":"0.25rem"}}
  >
    License
  </h3><a
    href={"https://www.apache.org/licenses/LICENSE-2.0.html"}
  >
    Apache-2.0
  </a>
</div>