> ## Documentation Index > Fetch the complete documentation index at: https://docs.fluz.app/llms.txt > Use this file to discover all available pages before exploring further. # Set Up Your Server to Interact With The Fluz JS Widget Installation of the Fluz Javascript widget is relatively straightforward. You must embed or import the Javascript onto a page on your site. Once the javascript has loaded in, you can bind a UI element to open the javascript modal included as part of the imported javascript. You must also include a JWT that pre-authorizes the user to complete a particular transaction, as described below. ## Create a "Pre-approved transaction" token. Since the user is interacting with the Fluz platform to move money in and out of your spend account, any interaction with the widget must include a signed JWT token that effectively "pre-authorizes" the user to complete the transaction. What this means is, for instance, if user "abc123" has \$50 in their operator account that they wish to withdraw to Fluz, you generate a `patToken` that Fluz can use to validate the transaction and amount. This patToken contains the `amount`, your `apiKey`, the `transactionType`, the `externalId`, user data, and then a JTI. This token is signed with your `apiSecret` that can be found in your app details in the `for-developers` section of Fluz. | key | value | | ---------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | amount | the amount in dollars and cents that the user is approved to transact with | | transactionType | `DEPOSIT` or `WITHDRAW`.
`DEPOSIT` means the user is putting money into Fluz, and then moving it to your operator spend account.
`WITHDRAW` means the user is doing a payout from your operator spend account to their Fluz account. | | apiKey | the API key of your app | | externalId | Your unique identifier for your user. Can be a userId, accountId, phone number, email address - whatever you use in your system. We will provide this when we send you information like webhook events, so you can map the user in your system. | | jti | a UUID v4 that is generated when you go to sign the token. We use this token for idempotency. You can read more [in the official jti spec](https://www.rfc-editor.org/rfc/rfc7519#section-4.1.7). | | phoneNumber (optional) | a string with phone number of user. If passed, user will skip the **Enter the phone number** step of login/registration and will be moved straight to **Enter the two-factor-authentication code** step | | firstName (optional) | a string with the first name of the user | | lastName (optional) | a string with the last name of the user | | email (optional) | a string with the email of user | | username (optional) | a string with the username | ## Code snippets to generate the JWT ### JavaScript ```javascript theme={null} import jwt from 'jsonwebtoken'; const { sign } = jwt; const amount = 0; // Pass in the amount here const transactionType = ""; // DEPOSIT or WITHDRAW const externalId = ""; // This is your unique identifier. It might be a userID, accountID. const jti = uuidv4(); const secret = ""; // Your api secret const generatedToken = sign({ amount, apiKey: "", // Your apiKey transactionType, externalId, jti, }, secret, { expiresIn: '1 day' }); ``` ### Ruby Installation: `gem install jwt` ```ruby theme={null} require 'jwt' require 'securerandom' amount = 0 # Pass in the amount here transaction_type = "" # DEPOSIT or WITHDRAW external_id = "" # This is your unique identifier. It might be a userID, accountID. jti = SecureRandom.uuid secret = "" # Your api secret payload = { amount: amount, apiKey: "", # Your apiKey transactionType: transaction_type, externalId: external_id, jti: jti, exp: Time.now.to_i + (24 * 60 * 60) # 1 day } generated_token = JWT.encode(payload, secret, 'HS256') puts generated_token ``` ### Python Installation: `pip install PyJWT` ```python theme={null} import jwt import uuid from datetime import datetime, timedelta amount = 0 # Pass in the amount here transaction_type = "" # DEPOSIT or WITHDRAW external_id = "" # This is your unique identifier. It might be a userID, accountID. jti = str(uuid.uuid4()) secret = "" # Your API_SECRET. Please reach out to your Fluz account manager if you do not have this. payload = { "amount": amount, "apiKey": "", # Your apiKey "transactionType": transaction_type, "externalId": external_id, "jti": jti, "exp": datetime.utcnow() + timedelta(days=1) } generated_token = jwt.encode(payload, secret, algorithm="HS256") print(generated_token) ``` ### Go ```go theme={null} package main import ( "fmt" "time" "github.com/golang-jwt/jwt/v5" "github.com/google/uuid" ) func main() { amount := 0 // Pass in the amount here transactionType := "" // DEPOSIT or WITHDRAW externalId := "" // This is your unique identifier. It might be a userID, accountID. jti := uuid.New().String() secret := "" // Your api_secret claims := jwt.MapClaims{ "amount": amount, "apiKey": "", // your api_key "transactionType": transactionType, "externalId": externalId, "jti": jti, "exp": time.Now().Add(24 * time.Hour).Unix(), } token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims) generatedToken, err := token.SignedString([]byte(secret)) if err != nil { fmt.Println("Error generating token:", err) return } fmt.Println(generatedToken) } ``` ### Java ```java theme={null} import io.jsonwebtoken.Jwts; import io.jsonwebtoken.SignatureAlgorithm; import java.util.Date; import java.util.HashMap; import java.util.Map; import java.util.UUID; public class JwtGenerator { public static void main(String[] args) { int amount = 0; // Pass in the amount here String transactionType = ""; // DEPOSIT or WITHDRAW String externalId = ""; // This is your unique identifier. It might be a userID, accountID. String jti = UUID.randomUUID().toString(); String secret = ""; // Your api_secret Map claims = new HashMap<>(); claims.put("amount", amount); claims.put("apiKey", ""); // your api_key claims.put("transactionType", transactionType); claims.put("externalId", externalId); long expirationTime = System.currentTimeMillis() + (24 * 60 * 60 * 1000); // 1 day String generatedToken = Jwts.builder() .setClaims(claims) .setId(jti) .setExpiration(new Date(expirationTime)) .signWith(SignatureAlgorithm.HS256, secret) .compact(); System.out.println(generatedToken); } } ``` ### PHP ```php theme={null} toString(); $secret = ""; // Your api_secret $payload = [ "amount" => $amount, "apiKey" => "", // your api_key "transactionType" => $transactionType, "externalId" => $externalId, "jti" => $jti, "exp" => time() + (24 * 60 * 60) // 1 day ]; $generatedToken = JWT::encode($payload, $secret, 'HS256'); echo $generatedToken; ?> ``` ### C# (.NET) ```csharp theme={null} using System; using System.Collections.Generic; using System.IdentityModel.Tokens.Jwt; using System.Security.Claims; using Microsoft.IdentityModel.Tokens; using System.Text; class JwtGenerator { static void Main() { int amount = 0; // Pass in the amount here string transactionType = ""; // DEPOSIT or WITHDRAW string externalId = ""; // This is your unique identifier. It might be a userID, accountID. string jti = Guid.NewGuid().ToString(); string secret = ""; // Your api_secret var claims = new List { new Claim("amount", amount.ToString()), new Claim("apiKey", ""), // your api_key new Claim("transactionType", transactionType), new Claim("externalId", externalId), new Claim(JwtRegisteredClaimNames.Jti, jti) }; var key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(secret)); var creds = new SigningCredentials(key, SecurityAlgorithms.HmacSha256); var token = new JwtSecurityToken( claims: claims, expires: DateTime.UtcNow.AddDays(1), signingCredentials: creds ); var generatedToken = new JwtSecurityTokenHandler().WriteToken(token); Console.WriteLine(generatedToken); } } ```