user22956: I have a Arduino Uno and the esp8266 module,(NOT THE SHIELD). 
I was looking for some library that I could use to connect to Wifi and set a webserver, but I can't find anything. I just found for Arduino Wifi Shield which uses SPI. 
It is possible to use arduino lets say to read a LM35 and then send that data to the ESP8266 module and serve it in a page as webserver?
I know that I can use AT commands with ESP8266 to connect to wifi and to create a server, but I cannot find any function to set the data to be served.
https://www.espressif.com/sites/default/files/documentation/4a-esp8266_at_instruction_set_en.pdf

user37857: For a webserver, program the ESP8266 directly. This allows you to make use of the internal SPI flash memory to store your webpages. You can't do this with AT commands.
The Arduino UNO does not have enough processing power and/or memory for advanced internet stuff. If you want a webserver over AT commands, the Arduino has to do all the hard work, the ESP8266 is just a dumb slave that establishes a TCP connection.
The ESP8266 is much faster, and has many times more memory, so it makes sense to let it do all the heavy lifting.
Take a look at this guide:
ESP8266 temperature logger
You can copy pretty much all code, but instead of measuring the temperature from an actual sensor, read it from the Serial input.
Then just connect the Arduino to the ESP8266 over Serial (or SPI or I²C or SoftwareSerial, whatever you prefer), and have it send the temperature to the ESP8266, for example every second.
To program the ESP8266, you can use the USB-to-Serial adapter of one of your Arduinos.

In this case, where you just want to read a single LM35, you could even use only the ESP8266. It is true that the LM35 requires at least 4V, but this is not a problem, since most ESP8266 dev boards also provide a 5V supply. The analog input range of 0-1.0V would allow for a temperature up to 100°C.

22956: <p>I have a Arduino Uno and the esp8266 module,(NOT THE SHIELD). </p>

<p>I was looking for some library that I could use to connect to Wifi and set a webserver, but I can't find anything. I just found for Arduino Wifi Shield which uses SPI. </p>

<p>It is possible to use arduino lets say to read a LM35 and then send that data to the ESP8266 module and serve it in a page as webserver?</p>

<p>I know that I can use AT commands with ESP8266 to connect to wifi and to create a server, but I cannot find any function to set the data to be served.</p>

<p><a href="https://www.espressif.com/sites/default/files/documentation/4a-esp8266_at_instruction_set_en.pdf" rel="nofollow noreferrer">https://www.espressif.com/sites/default/files/documentation/4a-esp8266_at_instruction_set_en.pdf</a></p>
 37857: <p>For a webserver, program the ESP8266 directly. This allows you to make use of the internal SPI flash memory to store your webpages. You can't do this with AT commands.</p>

<p>The Arduino UNO does not have enough processing power and/or memory for advanced internet stuff. If you want a webserver over AT commands, the Arduino has to do all the hard work, the ESP8266 is just a dumb slave that establishes a TCP connection.<br>
The ESP8266 is much faster, and has many times more memory, so it makes sense to let it do all the heavy lifting.</p>

<p>Take a look at this guide:
<a href="https://tttapa.github.io/ESP8266/Chap16%20-%20Data%20Logging.html" rel="nofollow noreferrer">ESP8266 temperature logger</a></p>

<p>You can copy pretty much all code, but instead of measuring the temperature from an actual sensor, read it from the <code>Serial</code> input.</p>

<p>Then just connect the Arduino to the ESP8266 over Serial (or SPI or I²C or SoftwareSerial, whatever you prefer), and have it send the temperature to the ESP8266, for example every second.</p>

<p>To program the ESP8266, you can use the USB-to-Serial adapter of one of your Arduinos.</p>

<hr>

<p>In this case, where you just want to read a single LM35, you could even use only the ESP8266. It is true that the LM35 requires at least 4V, but this is not a problem, since most ESP8266 dev boards also provide a 5V supply. The analog input range of 0-1.0V would allow for a temperature up to 100°C.</p>
