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Connect  ›  Connect PayU to WhatsApp
Payment connection guide

Connect PayU to WhatsApp

PayU's payment links API uses OAuth2 Bearer tokens rather than simple API keys. This guide covers the two-step process: getting a token, then creating a payment link, and sending it to a customer on WhatsApp.

 Published 21 June 2026  8 min read  Live-researched  India-first

PayU is one of India's most established payment gateways, processing a large share of domestic e-commerce transactions. Its newer REST API for payment links uses a standard OAuth2 token flow, which adds one step compared to Razorpay or Cashfree but is a well-understood pattern.

New to the External API Request step? Read the foundation guide first.

Step 1: Get your PayU credentials

1

Log in to your PayU merchant account

Go to payu.in and log in to your merchant account.
2

Find your Merchant Key and Secret

Under Settings or API Credentials, locate your Merchant Key and the corresponding Secret (sometimes called Client Secret for the OAuth flow). These are different from the Salt used in the older form-POST integration.
3

Get an access token

Call PayU's OAuth token endpoint with your client credentials to receive a Bearer access token. This token expires and must be refreshed. Store the token from the response and use it in the payment links request.

 Two-step process

PayU's payment links API requires a Bearer token, not a static API key. That means you first call a token endpoint to get an access_token, then use that token in the payment link creation call. Many automation builders chain these as two sequential External API Request steps.

 Official source

For the current token endpoint URL, scopes, and payment link parameters: docs.payu.in/reference/create-payment-links.

Step 2: Fill in the External API Request step

Once you have the access_token from step 1, use it in this step to create the payment link.

External API Request
Method
POST
Request URL
https://info.payu.in/payment-links
Auth Type
Bearer token
Header Parameters
Authorization
Bearer {{access_token}}
merchantId
YOUR_MERCHANT_ID
Content-Type
application/json
Body Type
JSON (raw)
Response Type
Default Response
SaveRun and Save

Endpoints

EnvironmentBase URL
UAT (testing)https://uatoneapi.payu.in/payment-links
Production (live)https://info.payu.in/payment-links

Headers

HeaderValue
AuthorizationBearer YOUR_ACCESS_TOKEN (from the token step)
merchantIdYour PayU Merchant ID
Content-Typeapplication/json

Body

JSON body
{
  "subAmount": 500,
  "isPartialPaymentAllowed": false,
  "description": "Payment for Order #{{order_id}}",
  "source": "API",
  "currency": "INR",
  "customer": {
    "name": "{{customer_name}}",
    "phone": "{{customer_phone}}",
    "email": "{{customer_email}}"
  }
}

subAmount is the payment amount in rupees (not paise). The response contains the payment link URL which you send to the customer on WhatsApp.

Troubleshooting

SymptomLikely causeFix
401 UnauthorizedExpired or invalid access tokenCall the token endpoint again to get a fresh token; tokens expire
403 ForbiddenWrong merchantId headerConfirm the merchantId matches the account that issued the token
422 UnprocessableMissing required body fieldEnsure subAmount, description, and source are all present
UAT link not working on a phoneUAT links only work in test modeExpected; use production endpoint and live credentials for real payments
Token expired mid-flowToken TTL exceededBuild a token refresh step at the start of your flow or cache the token with its expiry time

Common questions

Where do I get my PayU Merchant Key and Salt?
+
Log in to your PayU merchant account at payu.in. Go to Settings or Dashboard and look for API credentials. You receive a Merchant Key and a Salt (sometimes called Salt v1). Keep the Salt secret; it is used for hash calculation and must never appear in frontend code.
Does PayU use Bearer tokens or the merchant key directly?
+
PayU's newer payment links API uses OAuth2 Bearer tokens, which you obtain by calling a token endpoint with your merchant key and secret. The older payment form flow embeds the merchant key directly in a form POST. For the External API Request step in WA.Expert, the payment links API with Bearer auth is the right approach since it is a proper REST API that returns a usable link.
What is the hash in PayU and do I need it?
+
The hash is a SHA-512 checksum required for PayU's legacy form-POST payment flow. For the newer payment links API used in this guide, the hash is not required; Bearer token authentication covers security. Avoid the form-POST flow from WA.Expert's External API Request step since it is designed for web checkout pages, not API calls.
What is the difference between UAT and production for PayU?
+
PayU's sandbox is called UAT (User Acceptance Testing). The UAT endpoint is uatoneapi.payu.in. The production endpoint is info.payu.in. Merchant IDs, keys, and tokens are different for each. Always test on UAT first, then switch both the endpoint and credentials for production.
Does this cost anything on WA.Expert?
+
WA.Expert does not add a charge for the External API Request step beyond standard automation action pricing. PayU charges a per-transaction MDR (Merchant Discount Rate) deducted from the settlement amount. The WhatsApp message is free inside an active service window.
What is the best use of PayU inside a WhatsApp chatbot?
+
The most practical use is creating a payment link for a specific order or invoice and sending the link to the customer in the same WhatsApp message. The customer taps the link, pays using UPI, cards, or net banking on PayU's hosted page, and PayU sends a webhook confirming the payment.
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