@leash/seller-kit exports a handful of small helpers that don’t build transactions but every seller integration needs:
  • “Which stables can I price in on this network?”
  • “Where will my paywall settle through?”
  • “Did I write this price string correctly?”
  • “What’s the on-chain payTo for this agent?”
The TypeScript SDK gets these as plain function imports. Polyglot SDKs and UI dropdowns get them as four read-only HTTP endpoints under /v1/seller/* and /v1/agents/{mint}/pay-to. They do no DB writes and never call out to a facilitator or RPC node — every response is a pure derivation from the API’s compile-time registry.
EndpointMirrorsUse it for
GET /v1/seller/networksKNOWN_TOKENS + KNOWN_STABLE_SYMBOLSCurrency / network dropdowns
GET /v1/seller/facilitatordefaultFacilitatorFor + configShowing the buyer “settles via X” label
POST /v1/seller/parse-priceparsePrice from seller-kitValidating a draft price string
GET /v1/agents/{mint}/pay-tofindAssetSignerPda from mpl-coreResolving the on-chain payTo
Every endpoint is network-scoped via the API key prefix — there is no per-request network parameter. lsh_test_* keys see devnet mints, lsh_live_* keys see mainnet mints.

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GET /v1/seller/networks

Returns the full per-network token catalog plus the caller’s current network surfaced as current for convenience. 
GET /v1/seller/networks
Authorization: Bearer lsh_test_...

{
  "items": [
    {
      "network": "solana-devnet",
      "caip2": "solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1",
      "facilitator": "https://devnet-facilitator.leash.market",
      "accepts": ["USDC", "USDT", "USDG"],
      "tokens": [
        {
          "symbol": "USDC",
          "name": "USD Coin",
          "mint": "4zMMC9srt5Ri5X14GAgXhaHii3GnPAEERYPJgZJDncDU",
          "decimals": 6,
          "program": "spl-token",
          "stable": true
        },
        {
          "symbol": "USDT",
          "name": "Tether USD",
          "mint": "Es9vMFrzaCERmJfrF4H2FYD4KCoNkY11McCe8BenwNYB",
          "decimals": 6,
          "program": "spl-token",
          "stable": true
        }
      ]
    },
    {
      "network": "solana-mainnet",
      "caip2": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdpKuc",
      "...": "..."
    }
  ],
  "current": { "network": "solana-devnet", "...": "..." }
}
accepts[] is the same ordered list of stables every paywall and buyer endpoint uses (USDC, USDT, USDG), so you can wire it directly into a UI dropdown.

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GET /v1/seller/facilitator

Resolves the facilitator URL the caller-scoped network will settle through, with provenance. 
GET /v1/seller/facilitator
Authorization: Bearer lsh_test_...

{
  "network": "solana-devnet",
  "facilitator": "https://devnet-facilitator.leash.market",
  "source": "default"
}
source is "config" when the API operator has pinned LEASH_API_FACILITATOR_URL, and "default" when we fell back to the Leash default for the cluster (devnet-facilitator.leash.market on devnet, facilitator.leash.market on mainnet). Other facilitators can be used — see Run a Leash facilitator. UI tip: render this as a small “Settles via ” label next to your draft payment link so users know exactly which facilitator will broker the transfer.

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POST /v1/seller/parse-price

Parses a display price string into atomic units against the caller-scoped network’s stablecoin registry, and returns per-stablecoin equivalents you can preview. 
POST /v1/seller/parse-price
Authorization: Bearer lsh_test_...
Content-Type: application/json

{
  "price": "$0.001"
}

{
  "amount": "1000",
  "currency": "USDC",
  "asset": "4zMMC9srt5Ri5X14GAgXhaHii3GnPAEERYPJgZJDncDU",
  "network": "solana-devnet",
  "equivalents": [
    {
      "currency": "USDT",
      "amount": "1000",
      "asset": "Es9vMFrzaCERmJfrF4H2FYD4KCoNkY11McCe8BenwNYB"
    },
    {
      "currency": "USDG",
      "amount": "1000",
      "asset": "..."
    }
  ]
}
Pass an explicit currency to anchor the price to a specific stable instead of the USDC default: 
{ "price": "0.5", "currency": "USDT" }

{ "amount": "500000", "currency": "USDT", "...": "..." }
Accepted forms (same parser as the SDK):
FormResolves to
"$0.001"$0.001 in currency (default USDC).
"0.5" (bare num)0.5 units of currency (default USDC).
"0.5 USDT"0.5 USDT regardless of currency.
"1000 USDC"1000 USDC.
Unparseable inputs return 422 invalid_request with a message explaining what was tried.

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GET /v1/agents/{mint}/pay-to

Resolves the Asset Signer PDA for an agent — the on-chain account that receives funds when buyers pay through @leash/seller-kit or a hosted payment link. Pure PDA derivation via mpl-core; no RPC required. 
GET /v1/agents/BcN4ToBs8jE3dbYNhYqDJqGnKPjH3zRX8gsDUDH72JQp/pay-to
Authorization: Bearer lsh_test_...

{
  "agent_asset": "BcN4ToBs8jE3dbYNhYqDJqGnKPjH3zRX8gsDUDH72JQp",
  "network": "solana-devnet",
  "pay_to": "9pK9LhEt2zUWgSGRhJ6KCfb7vBCjwT5b7yT8sX6sR2tV"
}
This is the same value the paywall and the seller-kit advertise as payTo, so you can render it in a “Funds will land on ” field without ever touching mpl-core yourself.

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Why these exist

The TypeScript SDK already has all of this — it’s just import { parsePrice, KNOWN_TOKENS, defaultFacilitatorFor } from '@leash/seller-kit'. The HTTP surface exists for two reasons:
  1. Polyglot SDKs. A Python or Go client can’t import TypeScript. They get the same answers via REST and stay one release behind nothing.
  2. UIs. Dashboards, internal tools, and the explorer itself need a single source of truth for “supported currencies on this network” + “the facilitator we’ll settle through”. The endpoints make these dropdowns trivial without bundling the entire @leash/core registry into the browser.

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See also