AnyAmount Invoices

AnyAmount invoices allow the client to decide how much to pay. These are useful for donations, tips, or custom payments.

Key Differences from Regular Invoices

Items do not require a price field
Wrong and Refunded statuses are not applicable (no expected amount is defined, so underpayment and refunding are impossible)
Best practice is to use only one item/service/purpose per AnyAmount invoice

Create New AnyAmount Invoice

This endpoint creates a new AnyAmount invoice under merchant's account.

POST /api/invoices/v1/unlimited

Headers

Header	Value
`Content-Type`	`application/json`
`Authorization`	`Bearer YOUR_PUBLIC_TOKEN`

Request Body

Field	Type	Required	Description
`items`	array	Yes	Item or service provided by invoice. Can contain multiple items, but best practice for AnyAmount is one item/service/purpose
`items[].name`	string	Yes	Any desirable item name. Items don't require `price` for AnyAmount invoices as their concept is to let the client decide the amount
`isMerchantPaysFee`	boolean	No	`false` — client pays total + fees, merchant receives full amount. `true` — client pays total only, merchant receives total minus fees
`paymentCurrency`	string	No	Crypto asset the merchant wants to receive. If not provided or `null`, the client chooses
`redirectURL`	string	No	URL to redirect after invoice reaches "Done" status. If `null` or absent, the default from Settings/Payment is used

cURL

curl --location 'https://my.solopayment.com/api/invoices/v1/unlimited' \
  --header 'Content-Type: application/json' \
  --header 'Authorization: Bearer YOUR_PUBLIC_TOKEN' \
  --data '<body>'

Body:

{
    "items": [
        {
            "name": "Product 1"
        }
    ],
    "isMerchantPaysFee": null,
    "paymentCurrency": null,
    "redirectURL": "https://google.com"
}

Response

View response body

{
    "id": "invoice_id",
    "status": "created",
    "createdAt": "YYYY-MM-DDTHH:MM:SS.000Z",
    "type": "unlimited",
    "company": {
        "name": "%company_name",
        "logoUrl": "%logo_url%",
        "assets": [
            { "asset": "btc", "isAllowed": false },
            { "asset": "eth", "isAllowed": false },
            { "asset": "usdt", "isAllowed": false },
            { "asset": "sol", "isAllowed": false },
            { "asset": "ton", "isAllowed": false },
            { "asset": "usdc", "isAllowed": false },
            { "asset": "bnb", "isAllowed": false },
            { "asset": "ltc", "isAllowed": false },
            { "asset": "near", "isAllowed": false },
            { "asset": "trx", "isAllowed": false },
            { "asset": "bch", "isAllowed": false }
        ]
    },
    "invoiceContent": {
        "invoiceCurrency": "eur",
        "items": [
            { "name": "Product 1" }
        ],
        "paymentCurrency": "usdc",
        "isMerchantPaysFee": false,
        "redirectURL": "%url_for_DONE_statused_invoices_redirection%"
    }
}

Response Fields

Field	Description
`id`	Invoice identifier. Open on frontend: `https://pay.solopayment.com/%invoice_id%`
`status`	Current invoice state: `created`, `pending`, `processing`, `done`, `failed`, `expired`. Note: `wrong` and `refunded` are not applicable for AnyAmount invoices
`createdAt`	Invoice creation date and time
`type`	Invoice type: `regular`, `unlimited`, or `business`
`company`	Merchant's company information: `name`, `logoUrl`, `assets` (list of accepted assets with `isAllowed` flag)
`invoiceContent`	Primary invoice info: items list, `invoiceCurrency`, `paymentCurrency`, `isMerchantPaysFee`
`redirectURL`	URL for redirect after "Done" status. `null` means no redirect

Fill AnyAmount Invoice with Client Info

This endpoint fills an AnyAmount invoice with client's info — email address and payment asset (if not pre-defined by merchant during creation).

POST /api/invoices/v1/unlimited/%invoice_id%/proceed

Headers

Header	Value
`Content-Type`	`application/json`

Authorization is not required as the invoice is provided to a non-registered client.

Request Body

Field	Type	Required	Description
`clientEmail`	string	Yes	Client's email. Should meet standard email format
`paymentCurrency`	string	Yes	Asset name + network the client wants to pay with. Values: `btc`, `eth`, `trc20usdt`, `usdterc20`, `sol`, `ton`, `usdc`, `bnb`, `ltc`, `trx`, `bch`. Ignored if previously provided during creation
`paymentAmount`	number	Yes	Amount entered by the client as a reference of amount to be received in `invoiceCurrency`. Required for frontend correct work, can have any desirable value for API-only processing
`invoiceCurrency`	string	No	Invoice currency for payment amount reference to be calculated. Required for frontend correct work, can be ignored for API-only processing

cURL

curl --location 'https://my.solopayment.com/api/invoices/v1/unlimited/%invoice_id%/proceed' \
  --header 'Content-Type: application/json' \
  --data '<body>'

Body:

{
    "paymentCurrency": "usdc",
    "clientEmail": "client@example.com",
    "paymentAmount": 100,
    "invoiceCurrency": "eur"
}

Response

View response body

{
    "id": "%invoice_id%",
    "status": "%invoice_status%",
    "createdAt": "YYYY-MM-DDTHH:MM:SS.000Z",
    "type": "unlimited",
    "company": {
        "name": "%company_name%",
        "logoUrl": "%logo_url%",
        "assets": [
            { "asset": "btc", "isAllowed": true },
            { "asset": "eth", "isAllowed": false },
            { "asset": "usdt", "isAllowed": true },
            { "asset": "sol", "isAllowed": false },
            { "asset": "ton", "isAllowed": false },
            { "asset": "usdc", "isAllowed": false },
            { "asset": "bnb", "isAllowed": false },
            { "asset": "ltc", "isAllowed": false },
            { "asset": "near", "isAllowed": false },
            { "asset": "trx", "isAllowed": false },
            { "asset": "bch", "isAllowed": false }
        ]
    },
    "invoiceContent": {
        "items": [
            { "name": "Product 1" }
        ],
        "paymentCurrency": "trc20usdt",
        "isMerchantPaysFee": false,
        "paymentAmount": "100"
    },
    "redirectURL": "%url_for_DONE_statused_invoices_redirection%",
    "clientEmail": "client_mail@service.domain",
    "address": {
        "id": "%payment_address_id%",
        "address": "%payment_address%",
        "tag": null,
        "asset": "trc20usdt",
        "qrCodeURL": "string link to address QR-code generated",
        "qrCodeBase64": "string link to address QR-code generated in Base64"
    },
    "paymentDetails": {
        "rate": "1.16843920",
        "invoiceFee": "12.728032"
    },
    "expiredAt": "YYYY-MM-DDTHH:MM:SS.000Z"
}

Additional Response Fields

Fields available after the invoice is filled (not available for "Created" status):

Field	Description
`clientEmail`	Client's email
`address`	Payment address: `id`, `address`, `tag` (null if not TON), `asset`, `qrCodeURL`, `qrCodeBase64`
`paymentDetails.rate`	invoiceCurrency → paymentCurrency exchange rate
`paymentDetails.invoiceFee`	Fees in paymentCurrency
`expiredAt`	Invoice expiration time. 30 min for all assets, 120 min for BTC

Get AnyAmount Invoice Info

Use the same endpoint as Regular Invoices:

GET /api/invoices/v1/regular/%invoice_id%

See Regular Invoices — Get Invoice Info for details.

Create New AnyAmount Invoice​

Headers​

Request Body​

cURL​

Response​

Response Fields​

Fill AnyAmount Invoice with Client Info​

Headers​

Request Body​

cURL​

Response​

Additional Response Fields​

Get AnyAmount Invoice Info​

Create New AnyAmount Invoice

Headers

Request Body

cURL

Response

Response Fields

Fill AnyAmount Invoice with Client Info

Headers

Request Body

cURL

Response

Additional Response Fields

Get AnyAmount Invoice Info