EasyPay Integration

Updated: 7/26/26, 9:23:52 PM

Overview

EasyPay is DaxPay's built-in payment module compatible with mainstream EasyPay protocols, suitable for small merchants and individual developers.

DaxPay provides two API versions:

Version	Path Prefix	Signature	Capabilities
V1 (legacy)	/epay/api/v1/*	Fixed MD5	Only create (submit/mapi) + query (api); no refund/close
V2 (recommended)	/epay/api/v2/api/pay/*	Fixed RSA (SHA256withRSA)	Create, query, refund, refund query, close

Signatures are not interchangeable across versions

• V2's sign_type is fixed to RSA and does not accept MD5
• V1's sign_type is fixed to MD5 and does not accept RSA
• There is no "V2 chooses MD5 or RSA" — that's a misconception

Amount unit differs from standard API

EasyPay uses money (String, in yuan) for the amount field, not the standard API's amount (Long, in cents). E.g., "1.00" means 1 yuan.

V2 Endpoints

Endpoint	Path	Method	Description
Create	/epay/api/v2/api/pay/create	GET/POST	Create EasyPay order
Query	/epay/api/v2/api/pay/query	GET/POST	Query order status
Refund	/epay/api/v2/api/pay/refund	GET/POST	Initiate refund
Refund Query	/epay/api/v2/api/pay/refund_query	GET/POST	Query refund status
Close	/epay/api/v2/api/pay/close	GET/POST	Close order

refund_query alias

Refund query accepts both /api/pay/refund_query (underscore) and /api/pay/refundquery (no underscore) for compatibility with different EasyPay implementations.

V2 Create

Request

GET/POST /epay/api/v2/api/pay/create

Field names follow EasyPay protocol's snake_case style:

Parameter	Type	Required	Description
pid	string	Yes	EasyPay merchant number (maps to mchNo)
type	string	Yes	Interface type: web (redirect) / jump (direct to channel) / jsapi
method	string	No	Payment method: alipay / wxpay, etc.
out_trade_no	string	Yes	Merchant order number (maps to bizOrderNo)
name	string	Yes	Product name (maps to title)
money	string	Yes	Amount, in yuan (e.g., "1.00")
timestamp	string	Yes	Current timestamp (seconds)
notify_url	string	No	Async notification URL
return_url	string	No	Sync redirect URL
sign	string	Yes	RSA signature (Base64)
sign_type	string	Yes	Fixed RSA

Example Response

{
  "code": 0,
  "msg": "success",
  "data": {
    "orderId": 1853123456789012345,
    "orderNo": "P2024120112345700001",
    "payBody": "weixin://wxpay/bizpayurl?pr=xxxxx",
    "payBodyType": "qr_code"
  }
}

V2 Query

Request

GET/POST /epay/api/v2/api/pay/query

Parameter	Type	Required	Description
pid	string	Yes	EasyPay merchant number
out_trade_no	string	Yes	Merchant order number
sign	string	Yes	RSA signature
sign_type	string	Yes	Fixed RSA

Example Response

{
  "code": 0,
  "msg": "success",
  "data": {
    "orderNo": "P2024120112345700001",
    "status": "success",
    "realAmount": 100,
    "payTime": "2024-12-01 12:00:00"
  }
}

V2 Refund

Request

GET/POST /epay/api/v2/api/pay/refund

Parameter	Type	Required	Description
pid	string	Yes	EasyPay merchant number
out_trade_no	string	Yes	Original merchant order number
money	string	Yes	Refund amount, in yuan
out_refund_no	string	No	Merchant refund number (auto-generated if omitted)
sign	string	Yes	RSA signature
sign_type	string	Yes	Fixed RSA

V2 Signature Rule (RSA)

1. Collect all non-empty params, excluding sign and sign_type.
2. Sort by key in ASCII order.
3. Join as key1=value1&key2=value2 (no separator, no &key= suffix).
4. Sign with merchant private key using SHA256withRSA, Base64-encode, fill into sign.

Differences from standard Payment API signature

• Standard API (/unipay/*): camelCase param names (bizOrderNo), includes reqTime/nonceStr in signature
• EasyPay V2: snake_case param names (out_trade_no), includes timestamp, and excludes sign_type

Verification uses the platform public key, same as Signature.

V1 Endpoints (Legacy)

V1 endpoints are compatible with traditional EasyPay protocol paths. MD5 signature only:

Endpoint	Path	Method
Submit (redirect)	/epay/api/v1/submit.php	GET/POST
Create (API)	/epay/api/v1/mapi.php	GET/POST
Query	/epay/api/v1/api.php	GET/POST

V1 Limitations

• Create & query only: V1 does not provide refund, refund query, or close endpoints. For refunds use V2 or the merchant Management API.
• MD5 signature fixed: sign_type=MD5; uses merchant MD5 key appended at the end, then MD5 hash (lowercase hex).
• Weak query auth: V1 query uses direct key=md5Key comparison (query param), entirely different from V2's RSA verification — use only in low-risk scenarios.

V1 MD5 Signature Rule

1. Collect all non-empty params, excluding sign and sign_type.
2. Sort by key in ASCII order, join as key1=value1&key2=value2.
3. Append merchant key at end: ...&key={md5Key} (or directly appended per implementation).
4. MD5 the entire string, output lowercase hex.

Async Callback

EasyPay orders use protocol=easy_pay (GET + URL query params), different from the standard system protocol (POST JSON). See Async Callback - Two Notification Protocols.

Docs for AI Assistants

LLM-friendly document formats for ChatGPT, Claude, Cursor and other AI tools to read and understand DaxPay docs.

llms.txt — Site index, page list with summaries for quick lookup
llms-full.txt — Full docs merged, complete content in one file for bulk AI input