Whatsapp webhook callback endpoint not getting hit immediately

I am using Whatsapp cloud API. I have configured the webhook with a valid URL. It is working properly. But the issue is that once I receive a message from the business and if I send back a message immediately, the callback URL not getting invoked instantly. It waits for three minutes to invoke the endpoint. And if I wait for 3 minutes after a response and then send a message then it invokes instantly. Not able to find the reason. Nothing in the documentation also. I want to make it faster. For all the messages, the webhook should be triggered instantly.

https://developers.facebook.com/docs/whatsapp/cloud-api/get-started This is the documentation I followed.

Any help would be highly appreciable. Thanks in advance.

I tried sending back 200 OK for all the requests as per the documentation

My server code looks like this:

const fs = require('fs'); const token = process.env.ACCESS_TOKEN; // Imports dependencies and set up http server const request = require("request"),   express = require("express"),   body_parser = require("body-parser"),   axios = require("axios").default,   app = express().use(body_parser.json()); // creates express http server // Sets server port and logs message on success var https = require('https'); var credentials = {     key: fs.readFileSync(process.env.key),     cert: fs.readFileSync(process.env.cert),     ca: fs.readFileSync(process.env.ca, 'utf-8') } var httpsServer = https.createServer(credentials, app); httpsServer.listen(process.env.PORT, async () => {   console.log("Whatsapp server listening to port: "+process.env.PORT);   // await mysqlConnector.initializeMySql(app);   // await redis.initializeRedis(); }); 

And my webhook post method looks like this:

app.post("/inbound", async (req, res) => {   // Parse the request body from the POST   let body = req.body;   // Check the Incoming webhook message   // console.log(JSON.stringify(req.body, null, 2));   // info on WhatsApp text message payload: https://developers.facebook.com/docs/whatsapp/cloud-api/webhooks/payload-examples#text-messages   if (req.body.object) {     if (       body.entry &&       body.entry[0].changes &&       body.entry[0].changes[0] &&       body.entry[0].changes[0].value.messages &&       body.entry[0].changes[0].value. Messages[0]     ) {       res.sendStatus(200);        //if the business needs to send a text message       //async function call to send a text message (It is a promise function that makes API call to the /message endpoint of WhatsApp business API)        // if the business needs to send an interactive message       //async function call to send interactive message(promise function)     //if the business needs to send a template     //async function call to send message template(Promise function) } } } 

And the function that send the text message:

 sendMessage: async function (message, incomingMessageFrom, outgoingMessageFrom, accessToken) {     return new Promise(async function (resolve, reject) {       try {         axios({           method: "POST",           url: "https://graph.facebook.com/v16.0/" +             outgoingMessageFrom +             "/messages?access_token=" +             accessToken,           data: {             messaging_product: "whatsapp",             "to": incomingMessageFrom,             "type": "text",             "text": {               "body": String(message)             }           },           headers: { "Content-Type": "application/json" }         }).then(response => {           resolve(response.data)         });       } catch (error) {         //log Error         resolve("error: " + JSON.stringify(error.message));       }     })   } 

And the function that sends the template:

 sendMessageTemplate: async function (templateName, params, incomingMessageFrom, outgoingMessageFrom, accessToken) {     await this.bindParams(params, templateName);     return new Promise(async function (resolve, reject) {       try {         //call bind params         let data = {           "messaging_product": "whatsapp",           "to": incomingMessageFrom,           "type": "template",           "template": templates[templateName]         }         let url = "https://graph.facebook.com/v12.0/" +         outgoingMessageFrom +         "/messages?access_token=" +         accessToken;         axios({           method: "POST", // Required, HTTP method, a string, e.g. POST, GET           url:url,           data: data,           headers: { "Content-Type": "application/json" },         }).then(response => {           resolve(response.data)         }).catch(err =>{           appLogger.logMessage("error","Failed to call template api due to: "+JSON.stringify(err.message),className,"sendMessageTemplate","ADMIN","Server",moduleName);         });         appLogger.logMessage("debug","The request data send is: "+JSON.stringify(data),className,"sendMessageTemplate","ADMIN","SERVER",moduleName);         appLogger.logMessage("debug","The request url send is: "+url,className,"sendMessageTemplate","ADMIN","SERVER",moduleName);       } catch (error) {         appLogger.logMessage("error","error occured while sending message template: "+JSON.stringify(error.message),"sendMessageTemplate","ADMIN","SERVER",moduleName);         //logError         resolve("error: " + JSON.stringify(error.message));       }     })   }