JavaScriptSolidServer

HTTP 402 Paid Access

JSS supports two approaches to paid content:

  1. ACL Conditions — any resource at any URL can require payment via acl:condition in its ACL file
  2. Pay Route — the /pay/* prefix provides a full payment backend with deposits, balances, and token trading

ACL-Based Payments (Generic)

Any resource can be payment-gated by adding a PaymentCondition to its ACL:

{
  "@type": "acl:Authorization",
  "acl:agentClass": { "@id": "acl:AuthenticatedAgent" },
  "acl:accessTo": { "@id": "/premium/article.jsonld" },
  "acl:mode": [{ "@id": "acl:Read" }],
  "acl:condition": {
    "@type": "PaymentCondition",
    "amount": "1000",
    "currency": "sats"
  }
}

When a client requests the resource:

  1. Server evaluates the ACL and finds the PaymentCondition
  2. Server checks the agent’s balance in the webledger
  3. If balance >= cost — deducts and serves the resource (200)
  4. If balance < cost — responds with 402 Payment Required and payment details

To fund their balance, users deposit via the /pay/.deposit endpoint using a TXO URI (currently testnet4 for development). The balance is tracked in the webledger at /.well-known/webledgers/webledgers.json.

Design: fail-closed — if the server encounters a condition type it doesn’t support, access is denied. Unsupported conditions are never silently ignored.

Quick Demo

# Start JSS with payments (testnet4 by default)
jss start --pay --pay-cost 10

# Create an article and payment-gated ACL
curl -X PUT http://localhost:3000/premium/article.jsonld \
  -H "Content-Type: application/ld+json" \
  -d '{"@type": "Article", "headline": "Premium Content"}'

curl -X PUT http://localhost:3000/premium/article.jsonld.acl \
  -H "Content-Type: application/ld+json" \
  -d '{"@type":"acl:Authorization","acl:agent":{"@id":"did:nostr:YOUR_PUBKEY"},"acl:accessTo":{"@id":"/premium/article.jsonld"},"acl:mode":[{"@id":"acl:Read"}],"acl:condition":{"@type":"PaymentCondition","amount":"10","currency":"sats"}}'

# Try to read → 402 Payment Required
curl -H "Authorization: Nostr <nip98-token>" http://localhost:3000/premium/article.jsonld

# Deposit testnet4 sats
curl -X POST -H "Authorization: Nostr <nip98-token>" \
  http://localhost:3000/pay/.deposit -d 'txo:tbtc4:txid:vout'

# Try again → 200 OK + article
curl -H "Authorization: Nostr <nip98-token>" http://localhost:3000/premium/article.jsonld

Pay Route (Full Backend)

Monetize API endpoints with per-request satoshi payments. Resources under /pay/* require NIP-98 authentication and a positive balance.

jss start --pay --pay-cost 10 --pay-address your-address --pay-token PODS --pay-rate 10

Routes

Method Path Description
GET /pay/.info Public: cost, token info, chains, pool
GET /pay/.balance Check your balance (NIP-98 auth)
POST /pay/.deposit Deposit sats via TXO URI or MRC20 state proof
POST /pay/.buy Buy tokens with sat balance (requires --pay-token)
POST /pay/.withdraw Withdraw balance as portable tokens (requires --pay-token)
GET /pay/.offers List open sell orders (secondary market)
POST /pay/.sell Create a sell order (requires --pay-token)
POST /pay/.swap Execute a swap against a sell order
GET /pay/.pool AMM pool state (requires --pay-chains)
POST /pay/.pool AMM swap, add/remove liquidity
GET /pay/* Paid resource access (deducts balance)

How It Works

  1. Authenticate with NIP-98 (Nostr HTTP Auth)
  2. Check balance at /pay/.balance
  3. Deposit sats by POSTing a TXO URI to /pay/.deposit
  4. Access paid resources — each request deducts the configured cost
  5. Optionally buy tokens (/pay/.buy) or withdraw as portable tokens (/pay/.withdraw)
  6. Balance tracked in a Web Ledger at /.well-known/webledgers/webledgers.json

Example

# Check balance
curl -H "Authorization: Nostr <base64-event>" http://localhost:3000/pay/.balance

# Deposit (post a confirmed transaction output)
curl -X POST -H "Authorization: Nostr <base64-event>" \
  http://localhost:3000/pay/.deposit \
  -d "txid:vout"

# Access paid resource
curl -H "Authorization: Nostr <base64-event>" http://localhost:3000/pay/my-resource

# Buy tokens with sat balance
curl -X POST -H "Authorization: Nostr <base64-event>" \
  -H "Content-Type: application/json" \
  http://localhost:3000/pay/.buy \
  -d '{"amount": 100}'

# Withdraw entire balance as portable tokens
curl -X POST -H "Authorization: Nostr <base64-event>" \
  -H "Content-Type: application/json" \
  http://localhost:3000/pay/.withdraw \
  -d '{"all": true}'

Deposit verification uses the mempool API (default: testnet4). The X-Balance and X-Cost headers are returned on successful paid requests. Buy and withdraw return portable MRC20 proofs with Bitcoin anchor data for independent verification.

Secondary Market

Users can trade tokens peer-to-peer through the pod. Sell orders are created via /pay/.sell and filled via /pay/.swap. The pod acts as escrow — transferring tokens on the Bitcoin-anchored MRC20 trail and settling sats in the webledger.

Multi-Chain AMM

Enable multi-chain deposits and an automated market maker:

jss start --pay --pay-chains "tbtc3,tbtc4"

Deposits detect the chain from the TXO URI prefix (txo:tbtc3:txid:vout). Each chain’s balance is tracked separately. The AMM uses a constant-product formula (x × y = k) with a 0.3% fee.

# Add liquidity
curl -X POST -H "Authorization: Nostr <token>" \
  -H "Content-Type: application/json" \
  http://localhost:3000/pay/.pool \
  -d '{"action": "add-liquidity", "tbtc3": 1000, "tbtc4": 5000}'

# Swap
curl -X POST -H "Authorization: Nostr <token>" \
  -H "Content-Type: application/json" \
  http://localhost:3000/pay/.pool \
  -d '{"action": "swap", "sell": "tbtc3", "amount": 100}'

# Check pool state
curl http://localhost:3000/pay/.pool

Supported chains: btc, tbtc3, tbtc4, ltc, signet.

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