What Is Simple Cash?

What Simple Cash is

Simple Cash is an account-based payment service. Users link their bank account, verify it, and from that point on payments are debited directly from that account. The entire flow — authentication, account management, payments, refunds — is exposed as an API you integrate into your system.

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Simple Cash, defined

Simple Cash is an account-based payment service where users register and verify a bank account, then withdraw funds from it to pay.

Unlike card payments, there's no card number to enter. Once an account is registered, the payment flow is straightforward.

From the service side, the API gives you access to:

• User authentication
• Account verification and registration
• Payment requests
• Payment cancellation and refund
• Transaction queries
• Recurring payment management

Think of Simple Cash not as a basic bank transfer, but as a full-featured payment platform delivered through an API.

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Simple Cash API integration structure

The typical integration follows this sequence: user authentication → account registration → payment → transaction management.

Here's what each phase looks like.

1. User Identity Verification API

Before a payment can be initiated, you need to verify the user's identity.

This is handled through the mobile phone authentication API:

① Request mobile phone authentication
② Confirm authentication result

After this step, your service has the user's verified identity information.

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2. Account Verification API

Once identity is confirmed, the user enters the bank account they want to use for payments. You then verify that account is valid.

The relevant APIs are:

• Account holder name lookup
• Account ownership verification request
• Account ownership verification confirmation

The account holder lookup confirms the account exists. The ownership verification step confirms that the user is the actual owner of that account.

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3. Account Registration API

After account verification, you register the account in your system for use in future payments.

The key APIs here are:

• Account registration
• Account deregistration

Once registered, users can pay against that account without repeating the verification flow.

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4. Payment API

With an account registered, you can start processing payments.

The payment APIs cover:

• Payment request
• Payment cancellation (refund)

When you call the payment request API, the system debits the amount from the user's account and returns the result.

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5. Recurring Payment API

Simple Cash is well-suited for subscription services and automated billing.

The recurring payment APIs include:

• Recurring payment approval
• Recurring payment cancellation
• Recurring payment info query

These APIs let you build a subscription billing system that automatically charges users on a defined schedule.

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6. Transaction Query and Operations API

Running a production service means you'll need more than just payment initiation.

Key query APIs include:

• Transaction result query
• Transaction history query
• Bank list query
• Bank maintenance schedule query

For example, the result query API lets you re-verify a payment's outcome or check the current status of a transaction.

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Simple Cash is an account-based payment platform delivered as an API, applicable across a wide range of online services.

Developers can integrate user authentication, account registration, payment requests, and transaction queries through the API to build a payment flow tailored to their service.

Simple Cash is especially useful for services that need subscription billing or automated recurring payments. As online services diversify, account-based payment methods are becoming an increasingly important part of the stack.

Next: Simple Cash use cases and advantages →

Simple Cash documentation →