5.0 KiB
BUD-07
Paid upload and download
draft optional
Payment requirements for blob storage.
Payment Required
Some servers MAY require payment for file storage. In such cases, these endpoints MUST return a 402 Payment Required status code:
- HEAD /upload (Optional, if BUD-06 is implemented)
- PUT /upload
- HEAD /
- GET /
When payment is required, the server MUST include one or more X-{payment_method} header(s), each corresponding to a supported payment method.
Server headers
The 402 status code and X-{payment_method} header is used by the server to inform the client that a payment is required for the requested operation. The server MUST provide specific headers for each supported payment method.
Supported payment methods:
X-Cashu: Payment details for the cashu payment method, adhering to the NUT-18 standard.X-Lightning: Payment details for the lightning payment method, adhering to the BOLT-11 standard.
If a server supports multiple payment methods, it MAY send multiple X-{payment_method} headers in the same response.
Schema:
HTTP/1.1 402 Payment Required
X-Payment-{payment_method}: "<encoded_payload_according_to_{payment_method}_spec>"
X-Cashu Header
When using the X-Cashu header, the server MUST adhere to the NUT-18 standard.
Example for cashu:
HTTP/1.1 402 Payment Required
X-Cashu: creqApWF0gaNhdGVub3N0cmFheKlucHJvZmlsZTFxeTI4d3VtbjhnaGo3dW45ZDNzaGp0bnl2OWtoMnVld2Q5aHN6OW1od2RlbjV0ZTB3ZmprY2N0ZTljdXJ4dmVuOWVlaHFjdHJ2NWhzenJ0aHdkZW41dGUwZGVoaHh0bnZkYWtxcWd5ZGFxeTdjdXJrNDM5eWtwdGt5c3Y3dWRoZGh1NjhzdWNtMjk1YWtxZWZkZWhrZjBkNDk1Y3d1bmw1YWeBgmFuYjE3YWloYjdhOTAxNzZhYQphdWNzYXRhbYF4Imh0dHBzOi8vbm9mZWVzLnRlc3RudXQuY2FzaHUuc3BhY2U
X-Lightning Header
When using the X-Lightning header, the server MUST adhere to the BOLT-11 standard. Example for lightning:
HTTP/1.1 402 Payment Required
X-Lightning: lnbc30n1pnnmw3lpp57727jjq8zxctahfavqacymellq56l70f7lwfkmhxfjva6dgul2zqhp5w48l28v60yvythn6qvnpq0lez54422a042yaw4kq8arvd68a6n7qcqzzsxqyz5vqsp5sqezejdfaxx5hge83tf59a50h6gagwah59fjn9mw2d5mn278jkys9qxpqysgqt2q2lhjl9kgfaqz864mhlsspftzdyr642lf3zdt6ljqj6wmathdhtgcn0e6f4ym34jl0qkt6gwnllygvzkhdlpq64c6yv3rta2hyzlqp8k28pz
Client implementation
Clients MUST parse and validate the X-{payment_method} header received from the server. The client SHOULD provide a way for the user to complete the payment and retry the request using the same X-{payment_method} header.
The client MUST provide the payment proof when re-trying the request using the same X-{payment_method} header that was chosen. The payment proof MUST align with the payment method specification:
- For cashu the payment proof should be a serialized cashu token according to NUT-00.
- For lightning the payment proof should be the preimage of the payment request according to BOLT-11.
Schema:
X-{payment_method}: "<encoded_payment_proof_according_to_{payment_method}_spec>"
Example for Cashu:
X-Cashu: cashuBo2F0gqJhaUgA_9SLj17PgGFwgaNhYQFhc3hAYWNjMTI0MzVlN2I4NDg0YzNjZjE4NTAxNDkyMThhZjkwZjcxNmE1MmJmNGE1ZWQzNDdlNDhlY2MxM2Y3NzM4OGFjWCECRFODGd5IXVW
Example for Lightning:
X-Lightning: "966fcb8f153339372f9a187f725384ff4ceae0047c25b9ce607488d7c7e93bba"
Recurring Payments
Servers MAY accept recurring payments for blob storage using the following Nostr event types:
The event MUST include a custom x tag containing the hash of the blob being paid for.
x: A string that represents the blob's SHA-256 hash.
Error handling
If the client fails to provide the payment proof (expired invoice, invalid token, etc.) the server MUST respond with 402 Payment Required status code and include the relevant X-{payment_method} header(s) with updated payment details.
Extending with Future Payment Methods
To support future payment methods (e.g., other Layer 2 solutions), the specification allows the addition of new X-{payment_method} headers. Each new method MUST adhere to the following:
New methods MUST use a unique X-{payment_method} header containing the specific payment details.
New methods MUST adhere their own specification, which MUST be publicly available and linked in the header.
New methods MAY have a Nostr event type for recurring payments, which MUST be linked in the Recurring Payments section.