> ## Documentation Index
> Fetch the complete documentation index at: https://developers.1-funnel.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Application tutorials: build and run an integration

> Choose a runnable SMS or OTP application tutorial, test it locally, and follow the complete workflow from setup to saved outcomes and recovery.

A tutorial walks you through building and running a complete example, step by
step. Start here when you want working application code and a path from setup
to a saved result, including failure recovery.

A [task guide](/guides/overview) helps you use a specific API capability, such as
sending with a template or verifying a webhook signature. The
[API reference](/api-reference/overview) defines exact operations, request fields,
response schemas and errors. Use those alongside a tutorial when you need detail.

## Choose an application

* [Build an SMS status receiver with Node.js](/guides/tutorials/sms-status-node):
  save a send's idempotency key and message ID, verify and store webhook events,
  then retrieve and persist the current message status.
* [Verify an OTP challenge with Python](/guides/tutorials/otp-python): save a
  challenge against an application session, verify the recipient's code and
  handle wrong codes, expiry and uncertain responses.

Both tutorials use the public, Apache-2.0
[OneFunnel API samples repository](https://github.com/1funnel/1funnel-api-samples).
Each application has its own setup and offline tests; you do not need every
language runtime to run one example. The repository also has smaller Java and
cURL wallet request examples. These samples use ordinary HTTP clients, not
an official SDK.

## Start offline, then use Sandbox

Run the tutorial's offline tests first. They use local HTTP fixtures and do not
send SMS or require credentials. To exercise the actual API workflow, obtain
approved Sandbox access through the [Quickstart](/getting-started/quickstart)
and use your issued credentials and permitted test data. A passing local test
is not evidence of live API delivery or production readiness.

Each tutorial explains its runtime requirements, expected outcomes and
operational boundaries. Adapt and review the application before using it in
your own system.

## Improve or write a tutorial

Found a problem, need another language, or want to author a complete tutorial?
See [Community and contributions](/resources/community) for reporting, authoring
and pull-request instructions through the public samples repository.


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