> For the complete documentation index, see [llms.txt](https://docs.blynk.io/en/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.blynk.io/en/legacy-platform/legacy-articles.md).

# Legacy articles

{% hint style="warning" %}
This documentation is for the LEGACY version of Blynk platform which is no longer supported and will be shut down.

You can sign up for the current version of Blynk platform [here](http://blynk.cloud/dashboard/register).

The new mobile apps can be downloaded from [App Store](https://apps.apple.com/us/app/blynk-iot/id1559317868) and [Google Play](https://play.google.com/store/apps/details?id=cloud.blynk\&hl=en\&gl=US).

The actual Blynk documentation is [here](https://docs.blynk.io/).
{% endhint %}

Here are the articles in this section:

{% content-ref url="/pages/-MfmvkY3aL5M3BOdUB4d" %}
[What is Virtual Pins](/en/legacy-platform/legacy-articles/what-is-virtual-pins.md)
{% endcontent-ref %}

{% content-ref url="/pages/-MfmtevMtF\_ZF7snTFap" %}
[Keep your void loop() clean](/en/legacy-platform/legacy-articles/keep-your-void-loop-clean.md)
{% endcontent-ref %}

{% content-ref url="/pages/-MfmwVRsVdZhRss3ZIOL" %}
[How to control anything with Blynk app](/en/legacy-platform/legacy-articles/how-to-control-anything-with-blynk-app.md)
{% endcontent-ref %}

{% content-ref url="/pages/-Mfq8ulQ2D3f3KYPuLVF" %}
[NodeMCU](/en/legacy-platform/legacy-articles/nodemcu.md)
{% endcontent-ref %}

{% content-ref url="/pages/-Mfq96\_z\_ukRSCot6Dum" %}
[ESP8266 standalone](/en/legacy-platform/legacy-articles/esp8266-standalone.md)
{% endcontent-ref %}

{% content-ref url="/pages/-MfqAlG3Xu6Gb3E88s7i" %}
[Particle Electron](/en/legacy-platform/legacy-articles/particle-electron.md)
{% endcontent-ref %}

{% content-ref url="/pages/-Mfq9FgcFdc-Jxds0OlO" %}
[ESP8266 with AT firmware](/en/legacy-platform/legacy-articles/esp8266-with-at-firmware.md)
{% endcontent-ref %}

{% content-ref url="/pages/-Mfq9NbFd2ptPoRzEXnP" %}
[Bluetooth (2.0 SPP, 4.0 LE)](/en/legacy-platform/legacy-articles/bluetooth-2.0-spp-4.0-le.md)
{% endcontent-ref %}

{% content-ref url="/pages/-Mfq9URmCdje\_bKNH6bI" %}
[USB Serial](/en/legacy-platform/legacy-articles/usb-serial.md)
{% endcontent-ref %}

{% content-ref url="/pages/-MfqA4vWQFuu9oS03NpS" %}
[Raspberry Pi and Blynk](/en/legacy-platform/legacy-articles/raspberry-pi-and-blynk.md)
{% endcontent-ref %}

{% content-ref url="/pages/-Mfq9ofgFxtFOTNQfl19" %}
[BBC micro:bit + Arduino IDE](/en/legacy-platform/legacy-articles/bbc-micro-bit-+-arduino-ide.md)
{% endcontent-ref %}

{% content-ref url="/pages/-MfqAF4BAWSt-s825qXj" %}
[Blynk and Raspberry Pi: Tips & Tricks](/en/legacy-platform/legacy-articles/blynk-and-raspberry-pi-tips-and-tricks.md)
{% endcontent-ref %}

{% content-ref url="/pages/-MfqAQLpqvEOJDNFjIYD" %}
[How to install Node.js library on Linux](/en/legacy-platform/legacy-articles/how-to-install-node.js-library-on-linux.md)
{% endcontent-ref %}

{% content-ref url="/pages/-MfqAbaR71sXEFcAKfWe" %}
[Node.js vs. C++ library](/en/legacy-platform/legacy-articles/node.js-vs.-c++-library.md)
{% endcontent-ref %}

{% content-ref url="/pages/-MfqAtWy-4mcbY4My0Rz" %}
[Implementing a Blynk client (library)](/en/legacy-platform/legacy-articles/implementing-a-blynk-client-library.md)
{% endcontent-ref %}

{% content-ref url="/pages/-MfqEjlYYNbaYZyOu97Y" %}
[App and board logs. How to send application and board logs correctly](/en/legacy-platform/legacy-articles/app-and-board-logs.-how-to-send-application-and-board-logs-correctly.md)
{% endcontent-ref %}

{% content-ref url="/pages/-MfqEzIKe8r0URNeJ\_fC" %}
[Blynk Android permissions explained](/en/legacy-platform/legacy-articles/blynk-android-permissions-explained.md)
{% endcontent-ref %}

{% content-ref url="/pages/-MfmhSN0YXLa5yXyfCuW" %}
[How to find code for my hardware?](/en/legacy-platform/legacy-articles/getting-started.md)
{% endcontent-ref %}


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.blynk.io/en/legacy-platform/legacy-articles.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.