Payment Link API Authentication 1. Create payment link 2. Get payment link 3. Update payment link 4. Delete payment link

Payment Link API

Generate a unique, shareable payment URL programmatically. Ideal for invoicing software, accounting platforms, ERP systems, and any operational workflow where a specific, trackable payment link needs to be created and sent to a customer without redirecting them through a checkout session.

Best for: Zoho Books, QuickBooks, SAP, ERP payment collection, field sales, and any B2B workflow where the link is sent via email or SMS and paid independently.

Invoicing

Invoice-to-payment automation

Generate a link per invoice. When the customer pays, poll is_complete to auto-mark invoices as settled in your system.

ERP / Accounting

ERP-triggered collections

ERP raises an order → calls this API → attaches the link_url to the order record. Finance team tracks status directly in the ERP.

Partial Payments

Large-value partial collections

For amounts over LKR 100,000 or USD 100, enable allow_partial_payment to let customers pay in instalments. Minimum must be 30–100% of total.

Expiry Control

Time-limited payment requests

Set expiration_date to enforce payment deadlines. Expired links reject transactions, preventing late or duplicate payments.

Authentication

Payment Link API authenticates via a Company API Key passed in the Authorization header, different from the hash-based signing used by the Payment API. Your App ID is passed as a URL query parameter, not in the request body.

AUTHENTICATION HEADERS

HEADER	VALUE	REQUIRED
`Authorization`	Your company API key	Yes
`Content-Type`	`application/json`	Yes

1. Create payment link

POSThttps://api.onepay.lk/v3/payment-link/?app_id={app_id}

Create a new payment link with full customer and amount specifications. This link is immediately active upon creation until its expiration date.

QUERY PARAMETERS

PARAMETER	TYPE	DESCRIPTION
`app_id` required	string	Your OnePay App ID.

2. Get payment link

GEThttps://api.onepay.lk/v3/payment-link/{link_id}/?app_id={app_id}

Retrieve full details of a specific payment link using its 8-character link ID. Poll is_complete to detect when a customer has paid and trigger downstream ERP or accounting actions.

PATH & QUERY PARAMETERS

PARAMETER	TYPE	IN	DESCRIPTION
`link_id` required	string	Path	The 8-character payment link ID (e.g. `8IT20WK7`).
`app_id` required	string	Query	Your OnePay App ID.

RESPONSE PARAMETERS — 200 OK

Returns the same full object as the Create response. Key fields to watch:

FIELD	TYPE	DESCRIPTION
`data.is_complete`	boolean	`true` once the customer has fully paid. Use this to trigger order fulfillment in your system.
`data.is_delete`	boolean	`true` if the link has been soft-deleted.
`data.link_url`	string	The shareable payment URL.
`data.amount`	string	Original payment amount.
`data.expiration_date`	string	Link expiry date in `YYYY-MM-DD` format.
`data.created_at`	string	ISO 8601 creation timestamp.
`data.updated_at`	string	ISO 8601 last-updated timestamp.

3. Update payment link

PUThttps://api.onepay.lk/v3/payment-link/{link_id}/

Update the description of an existing payment link. Only the description field can be modified after creation. Amount, currency, reference number, customer details, and expiry date are all immutable to protect payment integrity.

PATH PARAMETERS

PARAMETER	TYPE	IN	DESCRIPTION
`link_id` required	string	Path	The 8-character payment link ID.

REQUEST BODY

PARAMETER	TYPE	DESCRIPTION
`app_id` required	string	Your OnePay App ID.
`description` required	string	The new description for the payment link.

RESPONSE PARAMETERS — 200 OK

FIELD	TYPE	DESCRIPTION
`status`	number	`200` on success.
`message`	string	Confirmation message.
`data`	object	Updated link object with all current fields reflecting the new description.

4. Delete payment link

DELETEhttps://api.onepay.lk/v3/payment-link/{link_id}/?app_id={app_id}

Soft-deletes a payment link by setting is_delete = true. The link record is preserved for audit purposes but becomes inactive immediately.

A link can only be deleted if it has no successful transactions associated with it. Attempting to delete a link with completed payments returns a 400 error.

PATH & QUERY PARAMETERS

PARAMETER	TYPE	IN	DESCRIPTION
`link_id` required	string	Path	The 8-character payment link ID.
`app_id` required	string	Query	Your OnePay App ID.

RESPONSE PARAMETERS

FIELD	TYPE	DESCRIPTION
`status`	number	`200` on successful deletion.
`message`	string	Confirmation message.

ERROR RESPONSE — 400

FIELD	TYPE	DESCRIPTION
`status`	number	`400` — deletion blocked.
`message`	string	"Cannot delete a link with successful transactions"

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