Marketplace MCP Server

marketplace-mcp

A NOSTR storefront for your LLM agent — speaks both dialects. MCP server that lets an agent create + update marketplace events on your behalf, in two dialects out of the box:

• NIP-15 (kind:30017 stalls + kind:30018 products) for NIP-15-native clients (Plebeian Market, etc.).
• Shopstr-modern (kind:30019 shop profile + kind:30402 NIP-99 classified listings) — what shopstr.store actually renders. Includes an automatic cache-POST so events appear on the storefront, not just on relays.

Seven tools, defense-in-depth safety, MIT licensed.

v0.2 — dual-dialect publisher. v0.1.x shipped NIP-15-only and the listings never appeared on shopstr.store because Shopstr is a Postgres-backed CMS that only renders events from its own DB (populated via POST /api/db/cache-event) and its cacheable-event allowlist excludes NIP-15 kinds. v0.2 adds the Shopstr-modern tools and the cache-POST hook so the storefront actually populates. NIP-15 tools left in place for non-Shopstr targets.

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Why this server exists

Shopstr (the canonical Bitcoin-Lightning marketplace UI on NOSTR) is not a relay-reading Nostr client — it's a Next.js app with a Postgres cache. Its marketplace page renders products from its own DB, populated when clients POST signed events to /api/db/cache-event. The cacheable-event allowlist (in shopstr-eng/shopstr → utils/db/cache-event-policy.ts) excludes NIP-15 stall/product kinds; modern Shopstr uses kind:30019 (shop profile with merchants: [<pubkey>]) and kind:30402 (NIP-99 Classified Listings, all data in tags). Without a ["t","shopstr"] tag the listing won't surface; without at least one ["image",<url>] tag the card silently never renders.

marketplace-mcp v0.2 builds the right events, POSTs them to Shopstr's cache after the relay publish, and keeps the legacy NIP-15 tools intact for anyone targeting other clients.

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What you can build with this

• A self-driving Shopstr storefront — agent generates shop profile + product listings from a config file, republishes whenever metadata changes, drops fresh t-tag categories per product for discoverability. Same call publishes to relays AND mirrors to Shopstr's cache.
• A sales-channel multiplexer — the same product events propagate to every NIP-15- or NIP-99-aware client (Shopstr, Plebeian Market, etc.) by virtue of being on shared relays. Pick your dialect per-tool; publish to both if your audience spans clients.
• A listing-as-code workflow — version-control your product JSON in git; CI calls shopstr_create_or_update_product to deploy. Republish with the same id = idempotent update (parameterized-replaceable events).
• Cross-server identity — pair with nostr-ops-mcp and nwc-mcp to wire identity + commerce. Same signer, same npub, three specialized tool surfaces.

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The seven tools

Shopstr-modern (new in v0.2) — required for shopstr.store visibility

NIP-15 legacy — for NIP-15-native clients (not Shopstr)

Common

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Requirements

• Node 20+
• A NOSTR signer — strongly preferred: a NIP-46 bunker URI from Amber, nsec.app, or any NIP-46 implementation. Dev path: raw nsec in .env.
• Relays your audience reads from. Sensible defaults in .env.example (relay.damus.io, nos.lol, relay.nostr.band, relay.primal.net).
• For Shopstr-modern publishes: outbound HTTPS to shopstr.store (or your own Shopstr deployment).

Install

# From npm
npx -y marketplace-mcp

# From source
git clone <repo>
cd marketplace-mcp
corepack enable pnpm
pnpm install
pnpm build

Configure

cp .env.example .env
# edit .env: set NOSTR_NIP46_URI OR NOSTR_PRIVATE_KEY
#           set NOSTR_RELAYS (comma-separated wss://)
#           set SHOPSTR_CACHE_ENABLED=true (default) for shopstr.store visibility

The server auto-loads .env from this binary's own directory (next to dist/) — deliberately NOT from cwd, to avoid env-var collision when multiple MCP servers run in the same Claude Code session.

Required

Signer — provide AT MOST one (without a signer the server runs read-only)

Shopstr cache mirror (new in v0.2)

shopstr.store reads from its own Postgres DB, not from open relays. After kind:30019/30402 events publish to relays, the server POSTs them to the configured cache URL so the storefront surfaces them. Failures are logged in the audit log but never roll back the relay publish (a Nostr event already broadcast can't be rolled back anyway).

The NIP-15 tools (kind:30017/30018) ignore these — those kinds aren't on Shopstr's cacheable allowlist anyway.

Optional safety knobs

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Quickstart: publish your first storefront on shopstr.store

1. agent: shopstr_create_or_update_shop({
     name: "My Shop",
     about: "Hand-crafted MCP servers and other Lightning-priced goods.",
     picture: "https://example.com/avatar.png",
     banner: "https://example.com/banner.png"
   })
   → returns { event_id, kind: 30019, relays_accepted: [...],
                after_publish: { shopstr_cache: { ok: true, status: 200 } } }

2. agent: shopstr_create_or_update_product({
     id: "some-product",
     name: "Some Product",
     summary: "Long-form description goes here. Becomes the event `content`.",
     price: 50000,
     currency: "sat",
     location: "online",
     shipping_option: "Free",
     shipping_cost: 0,
     images: ["https://example.com/card.jpg"],   // REQUIRED — Shopstr drops cards with zero images
     categories: ["software", "lightning", "mcp"]
   })
   → returns { event_id, kind: 30402, relays_accepted: [...],
                after_publish: { shopstr_cache: { ok: true, status: 200 } } }

Visit https://shopstr.store/marketplace/<your-npub> to see your storefront. (If you've registered a Shopstr profile slug for your npub, the URL canonicalises to /marketplace/<your-slug>.) Browsers buy through Shopstr's invoice-generation flow → sats land in the Lightning wallet linked to your Shopstr profile.

NIP-15 alternative (for non-Shopstr clients)

If you're targeting NIP-15-native clients instead of (or in addition to) Shopstr, the legacy tools still work:

agent: marketplace_create_or_update_stall({
  id: "my-shop", name: "My Shop",
  shipping: [{ id: "digital", name: "Digital", cost: 0 }]
})
agent: marketplace_create_or_update_product({
  id: "p1", stall_id: "my-shop", name: "Some Product",
  price: 50000, currency: "sat",
  shipping: [{ id: "digital", cost: 0 }]
})

You can publish both dialects for the same product to maximise client coverage; they don't collide.

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Wire into an MCP client

{
  "mcpServers": {
    "marketplace": {
      "command": "npx",
      "args": ["-y", "marketplace-mcp"],
      "env": {}
    }
  }
}

Same .env-via-binary-dir pattern as the rest of the substrate — leave the env block empty in client config; secrets stay in marketplace-mcp/.env.

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Safety model

The publish pipeline runs in this order, for both NIP-15 and Shopstr-modern tools:

1. NOSTR_READ_ONLY gate.
2. Signer presence — refuse if no signer.
3. RateLimiter — rolling events bucket (NOSTR_MAX_EVENTS_PER_MINUTE).
4. Confirm gate — if NOSTR_REQUIRE_CONFIRM=true, returns a token; marketplace_confirm_publish executes. The confirm dispatcher routes by tool name so Shopstr-modern publishes re-attach their cache-POST hook automatically.
5. Sign + publish via NDK.
6. afterPublish hook (Shopstr-modern only) — POST the signed event to SHOPSTR_CACHE_URL. Failures logged in audit (after_publish.shopstr_cache.{ok, status, error}) but never roll back the relay publish.
7. Audit log entry.

KindAllowlist is omitted because the kinds (30017/30018/30019/30402) are hard-coded in the tool implementations — there's no agent-supplied kind to validate.

If you want stricter behavior, pair with nostr-ops-mcp and use its kind allowlist on the same npub — but most users find that overhead unnecessary for a single-purpose marketplace server.

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Testing

pnpm typecheck
pnpm test        # 19 vitest cases (NIP-15 builders/parsers + Shopstr-modern builders/parsers + roundtrips)
pnpm build       # ~37 KB ESM bundle

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Companion servers

• nwc-mcp — Lightning wallet. The "payment" side of selling.
• nostr-ops-mcp — General NOSTR primitives. The marketplace MCP is the specialized cousin; nostr-ops-mcp is the generalist.
• albyhub-admin-mcp — Hub-level admin via Alby Hub's HTTP API. The other half of the wallet story (NWC handles payments, this handles node/channel/sub-wallet ops).

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License

MIT — see LICENSE.

Contact / Issues

Built by LLMOps.Pro.

• NOSTR: npub1hdg932jvwc3jdvkqywgqv0ue4nn60exrf92asy8mtazt3hjg7d2s2yw0nw — follow, DM, zap.
• Lightning Address: sovereigncitizens@getalby.com — for support zaps and "this was useful" tips.
• Bug reports / feature requests: open a GitHub issue (link forthcoming).
• Security issues: please disclose privately via NOSTR DM before opening a public issue.