Comments on: ESP32 DHT11/DHT22 Web Server – Temperature and Humidity using Arduino IDE

By: Sara Santos

Sara Santos — Fri, 13 Feb 2026 17:48:29 +0000

In reply to Alice.

Hi.
I’m sorry, it was my mistake. It’s not ESP32AsyncWebServer it’s ESPAsyncWebServer. And it’s the one by ESP32Async.

Regards,
Sara

By: Alice

Alice — Thu, 12 Feb 2026 16:13:43 +0000

Hi Sarah, and thanks for your reply. I think I was fooled (or maybe I am the fool) by the words ” Source code (zip)” since I took it to be some C++ file or a .h file at best, so I did not download it until this morning where I now see that it contains much more, including the library file. So thanks for pointing me in the right direction. BTW, the 3.9.6 version (as of today) and the author (maintainer) was helpful to convince me that I was heading in the correct direction.

But (I have Arduino IDE Version: 2.3.7) and when I type in ESP32AsyncWebServer I get nothing. I mean it is totally blank below the ‘Topic’ box. Then I try “espasyncwebserver” and I THEN see the 3rd library is the one you said, then I went back and typed it into the filter box again and THEN it appeared. At first, it looked case sensitive, but then it wasn’t. I don’t understand, but oh well, there’s lots of things that I don’t understand. That’s why I am trying to learn. Perhaps I’m too much a corner case.

I have those libraries now so I’ll try again.

Nevertheless, thanks for pointing me correctly.
Regards,
Alice

By: Sara Santos

Sara Santos — Thu, 12 Feb 2026 10:23:50 +0000

In reply to Alice.

Hi.
You must install the libraries by ESP32Async.
For the ESPAsyncWebServer, it is the third option in the Arduino library manager. Currently version 3.9.6.

For the AsyncTCP, it is the second option (also by ESP32Async), version 3.4.10 at the moment.

You should only have one ESP32AsyncWebServer library installed. So, you need to delete all the other ones you have installed previously, including their folders in the Arduino libraries folder.

Regards,
Sara

By: Alice

Alice — Thu, 12 Feb 2026 00:34:16 +0000

I keep getting a compile error, no matter what I try. I never got it to compile so I never got to try it. I have an ESP32-S3 (actually 3 of them). I have tried several ESP libraries, but there are now several that show up in the Arduino IDE library Manager dialog pane (Feb 2026). There are ESP Async WebServers or srv et.al, by various authors, which one is supposed to work with your sketch? Can you tell me which exact libabries to use and the versions and authors, so that I can get the correct ones. Thanks much and BTW your tutorials are my ‘go-to’ for most things, so thanks much!

By: Sara Santos

Sara Santos — Wed, 29 Oct 2025 14:27:27 +0000

In reply to Rui.

Hi.
Look at this error ” ESPAsyncTCP: No such file or directory”

You’re missing the installation of the ESPAsyncTCP library.
Regards,
Sara

By: Rui

Rui — Tue, 28 Oct 2025 18:24:39 +0000

Thanks a lot for sharing this tutorial.
I´m getting this error, can you please help?
I installed all the libraries several times…

AVISO: Categoria inválida «Sound» na biblioteca ESP_SR. Alterando para «Uncategorized»
AVISO: Categoria inválida «Security» na biblioteca Hash. Alterando para «Uncategorized»
AVISO: Categoria inválida «» na biblioteca ESP Insights. Alterando para «Uncategorized»
AVISO: Categoria inválida «» na biblioteca ESP RainMaker. Alterando para «Uncategorized»
AVISO: Categoria inválida «» na biblioteca TFLite Micro. Alterando para «Uncategorized»
AVISO: Categoria inválida «» na biblioteca WiFiProv. Alterando para «Uncategorized»
G:\O meu disco\Trabalho outros\Meus projectos\Arduino\ESP32\sensor temp\dht22\dht22.ino:9:10: fatal error: ESPAsyncTCP: No such file or directory
9 | #include
| ^~~~~~~~~~~~~
compilation terminated.

Foram encontradas múltiplas bibliotecas para «WiFi.h»
Utilizado: C:\Users\Rui\AppData\Local\Arduino15\packages\esp32\hardware\esp32\3.3.2\libraries\WiFi
Não utilizado: C:\Program Files (x86)\Arduino\libraries\WiFi
exit status 1
Erro ao compilar para a placa DOIT ESP32 DEVKIT V1.

By: Sara Santos

Sara Santos — Mon, 04 Aug 2025 15:51:48 +0000

In reply to Frank.

Great.
I’m glad it is working.
Regards,
Sara

By: Frank

Frank — Mon, 04 Aug 2025 13:31:38 +0000

In reply to Sara Santos.

Hello Sara,

It works ! did not think of it, I tried slasb, backslash, … none of them worked.

Thank you,
Frank.

By: Sara Santos

Sara Santos — Thu, 31 Jul 2025 17:42:05 +0000

In reply to Frank.

Hi.
Try adding two %% instead of one.
For example, instead of width:50% you would have width:50%%

Let me know if this fixes the issue.

Regards,
Sara

By: Frank

Frank — Thu, 31 Jul 2025 15:03:17 +0000

Hello, great tutorial !
I want to put a % sign is the style sheet, but the processsor try to replace the following string with something anb break the html page.
How can I do that ? % sign are important in style sheet !
Or is it possible to change the % sign in the ESPAsyncWebServer ?

Thanks