For high frequency payment flows, like ride sharing or delivery apps, you can allow your user to save a Payment Method (a card o a bank account), so their next payments will have less steps.

There are 2 ways to save a user's payment method using Fintoc:

1. Save during a payment: creating a Checkout Session of flow: payment, you can add the attribute save_payment_method: enabled. So your customer will have the option to save the method for future payments.
2. Save without a current payment: You can create a Checkout Session with flow: setup to allow users to enroll a method without processing a payment.

Option 1 — Save during a payment (recommended)

The customer pays and their payment method is saved in a single step.

Create a Customer

Every saved payment method must belong to a Customer. Create one first if you don't have one already.

curl -X POST https://api.fintoc.com/v2/customers \
  -H "Authorization: sk_live_xxx" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "Juan Pérez",
    "email": "[email protected]"
  }'

Save the returned id (e.g. cus_3B2bODrQFje7ZVkT69xyaTSDwXQ).

Create a Checkout Session with save_payment_method

Create a Checkout Session with the ID of thecustomer,flow: "payment" and save_payment_method: "enabled". So Fintoc will process the payment and store the customer's credentials for future use, if they choose to save it during the flow.

curl -X POST "https://api.fintoc.com/v2/checkout_sessions" \
  -H "Authorization: sk_live_xxx" \
  -H "Content-Type: application/json" \
  -d '{
    "flow": "payment",
    "customer": "cus_xxxxx",
    "amount": 5000,
    "currency": "CLP",
    "success_url": "https://yoursite.com/success",
    "cancel_url": "https://yoursite.com/cancel",
    "save_payment_method": "enabled"
  }'

Redirect the customer

Use the redirect_url to redirect the customer to the Fintoc-hosted page. Where they will have payment flow and the option to save credentials for future payments.

Handle post-payment events

Always use webhooks to determine the final outcome. Users may close the tab, lose connection, or never reach your success_url.

Checkout Session events

• checkout_session.finished: Sent when a Checkout Session reaches a final successful state. it must include the payment outcome, and if the user opted in, include the payment_method.id

  Example payload:

  JSON

  {
      "id": "cs_VvO7kpUMWlq2N10B",
      "flow": "payment",
      "mode": "test",
      "amount": 5000,
      "object": "checkout_session",
      "status": "finished",
      "currency": "CLP",
      "customer": {
          "id": "cus_xxxxx",
          "mode": "live",
          "name": null,
          "email": "[email protected]",
          "phone": null,
          "object": "customer",
          "tax_id": {
              "type": "cl_rut",
              "value": "257932338"
          },
          "address": null,
          "metadata": {},
          "created_at": "2026-03-16T19:41:17Z"
      },
      "metadata": {},
      "cancel_url": "https://yoursite.com/cancel",
      "created_at": "2026-03-30T20:47:41Z",
      "expires_at": "2026-03-31T20:47:41Z",
      "line_items": null,
      "success_url": "https://yoursite.com/success",
      "redirect_url": "https://pay.fintoc.com/payment?checkout_session=cs_VvO7kpUMWlq2N10B",
      "setup_intent": null,
      "subscription": null,
      "session_token": "cs_VvO7kpUMWlq2N10B_sec_UuSuPYRuEQTcWKXT6ba9LDTh",
      "customer_email": null,
      "payment_method": "pm_3BgHP7aSqsqLiEcotFQfyx7Of8u",
      "business_profile": null,
      "payment_resource": {
          "payment_intent": {
              "id": "pi_3BgHFvey4Qj4QZvTTZwyLL9OfSA",
              "mode": "test",
              "amount": 5000,
              "object": "payment_intent",
              "status": "succeeded",
              "currency": "CLP",
              "metadata": {},
              "created_at": "2026-03-30T20:48:12Z",
              "expires_at": null,
              "next_action": null,
              "error_reason": null,
              "payment_type": "bank_transfer",
              "reference_id": "575930",
              "widget_token": null,
              "customer_email": null,
              "sender_account": {
                  "type": "checking_account",
                  "number": "19831940978",
                  "holder_id": "257932338",
                  "institution_id": "cl_banco_falabella"
              },
              "business_profile": null,
              "transaction_date": "2026-03-30T20:49:00Z",
              "recipient_account": {
                  "type": "checking_account",
                  "number": "922358017",
                  "holder_id": "771433855",
                  "institution_id": "cl_banco_security"
              },
              "payment_type_options": {}
          }
      },
      "save_payment_method": "enabled",
      "payment_method_types": [
          "bank_transfer",
          "card"
      ],
      "payment_method_options": {}
  }

Payment Method events

If the customer chose to save the method, you will also receive a payment_method.activated with the info of the new saved payment method:

{
  "id": "pm_3BgHP7aSqsqLiEcotFQfyx7Of8u",
  "object": "payment_method",
  "card": null, 
  "created_at": "2021-10-15T15:22:11.474Z",
  "customer": "cus_NffrFeUfNV2Hib",
  "mode": "live",
  "metadata": {},
  "bank_transfer": {
    "account_holder_id": "257932338",
    "account_number": "19831940978",
    "account_type": "checking_account",
    "institution_id": "cl_banco_falabella",
    "status": "active",
  },
  "type": "bank_transfer"
}

You should suscribe to all the following post-session events:

Option 2 — Save a method without a current payment

Create a Setup session

The Checkout Session object represents your intent to save a payment method and/or collect a payment.

Using your Secret Key, create a Checkout Session from your backend with the flow: setup:

curl --request POST "https://api.fintoc.com/v2/checkout_sessions" \
  --header "Authorization: YOUR_SECRET_API_KEY" \
  --header "Content-Type: application/json" \
  --data-raw '{
    "flow": "setup",
    "currency": "CLP",
    "success_url": "https://merchant.com/success",
    "cancel_url": "https://merchant.com/cancel",
    "customer_data": {
      "email": "[email protected]"
    },
    "metadata": {}
  }'

📘

Send the payment_method_options to pre select a bank for your user

You have the option create the Checkout Session in Fintoc with an specific bank sending its institution_id inside the sender_account of the payment_method_options, so your user will only be able to save a bank account of that specific institution. You can also send the RUT of the user as the holder_id, so it will be already filled on the flow.

It is recommended when you ask your user to decide the bank on your flow, before creating the session in Fintoc. So the user will not have to select bank twice.

Redirect the customer

After creating a session, you receive a redirect_url that you must use to redirect your user so they can enroll their bank account as a saved payment method.

Handle post-session events

You should suscribe to the same post-session events mentioned for the Payment flow

Create a payment session with a saved payment method

If your customer has a bank_transfer saved payment_method , you can create a Checkout Session for a payment using it. So they will be redirected direct to the step to approve the payment with their bank, without having to initiate session with their credentials.

curl --request POST "https://api.fintoc.com/v2/checkout_sesisons" \
  --header "Authorization: YOUR_SECRET_API_KEY" \
  --header "Content-Type: application/json" \
  --data-raw '{
    "amount": 100000,
    "currency": "CLP",
    "flow": "payment",
    "success_url": "https://merchant.com/success",
    "cancel_url": "https://merchant.com/cancel",
    "customer": "cus_123",
    "payment_method": "pm_1NkL7QKs215JZ1LyW4c1m9Ut",
    "payment_method_types": [
      "bank_transfer"
    ]
  }'

Redirect the customer

Use the redirect_url to redirect the customer to the Fintoc-hosted page. Where they will go direct to the bank approval step, without having to initiate session with their credentials.

Handle post-payment events

After the payment, you will receive the checkout_session and payment_intent webhook events, confirming the final status of the session and payment:

Test your integration

Using your test mode API Secret Key, you can create Checkout Sessions that simulate successful and failed outcomes without moving any money.

This lets you validate your full setup and payment flow end-to-end:

• Your backend API requests (creating sessions and handling responses)
• The redirect flow from your frontend to the redirect_url and back to the success_url or cancel_url after the setup or payment
• Webhook for post-session events to save customer, payment_method and the payment result
  • After a successful setup o payment saving a payment_method, test creating a payment session using the saved method of the customer

To learn how to trigger specific scenarios, use the test credentials and special test values described in our testing guide.