How to set up a JSON for multiple variables in a webhook integration

Getting Started
7

You can send ALL the ThinkSpeak Fields in 1 snprintf if you want.
I looked at several examples on this forum and this is what I found:

snprintf(msg, sizeof(msg), 
// ThingSpeak Field #1  , ThingSpeak Field #2   ,  ThingSpeak WriteKey  
   "{\"1\":\"%.1f\"     ,   \"2\":\"%.1f\"      ,   \"k\":\"%s\"}"      ,
// Float for Field #1   , Float for Field #2    ,  ThingSpeak WriteKey     
        field1          ,       field2          ,   myWriteAPIKey)      ;

Particle.publish(eventName, msg, PRIVATE, NO_ACK);

Flash this code and play around with it:

// Snprintf example
const char * myWriteAPIKey = "xxxxxxxxxxxxxx";      //  From your ThingSpeak Account Info (API KEYS tab)
const char * eventName = "thingSpeakWrite_";        // This must match the name of the event you use for the WebHook

float field1 = 1.1;
float field2 = 2.1;

char msg[256];

void setup() {
}

void loop() {

snprintf(msg, sizeof(msg), 
// ThingSpeak Field #1  , ThingSpeak Field #2   ,  ThingSpeak WriteKey  
   "{\"1\":\"%.1f\"     ,   \"2\":\"%.1f\"      ,   \"k\":\"%s\"}"      ,
// Float for Field #1   , Float for Field #2    ,  ThingSpeak WriteKey     
        field1          ,       field2          ,   myWriteAPIKey)      ;

Particle.publish(eventName, msg, PRIVATE, NO_ACK);

field1 = field1 + 0.1;
field2 = field2 + 0.1; 

delay(20000);  // Wait 20 seconds before sending ThingSpeak.com more data.
}

/*
Sending 4 Fields to ThingSpeak (Floats, w/ 1 decimal precision) would look like this:
snprintf(msg, sizeof(msg), 
"{\"1\":\"%.1f\"    ,   \"2\":\"%.1f\"     ,  \"3\":\"%.1f\"   ,   \"4\":\"%.1f\"  ,   \"k\":\"%s\"}"      ,
     field1         ,       field2         ,       field3      ,       field4      ,   myWriteAPIKey)      ;
*/