• Data Vending Machines (NIP-90)
  • The Model
  • Event Types
    • Job Request (Kind 5000–5999)
    • Job Result (Kind 6000–6999)
    • Job Feedback (Kind 7000)
  • Payment Flow
    • Pre-paid (bid on request)
    • Post-paid (invoice in result)
  • NIP-89 Integration
  • Provider Selection
  • Example Providers
  • Building a DVM
  • Reputation System

§Data Vending Machines (NIP-90)

A marketplace for computation on Nostr. AI agents, oracles, and services sell work for sats.

§The Model

CUSTOMER                  RELAYS                   DVM PROVIDER
   │                         │                          │
   │──Job Request (5xxx)───▶│                          │
   │   - What to do          │                          │
   │   - Bounty offered      │                          │
   │                         │──Job Request───────────▶│
   │                         │                          │──Read request
   │                         │                          │──Compute result
   │                         │                          │──Optionally wait for payment
   │                         │◄──Job Result (6xxx)─────│
   │◄──Job Result───────────│                          │
   │   - Result content      │                          │
   │   - Payment request     │                          │
   │                         │                          │
   │──Feedback (7000)──────▶│                          │
   │                         │──Feedback──────────────▶│

§Event Types

§Job Request (Kind 5000–5999)

Specific kinds are assigned by DVM implementations:

• 5000–5099: Text/chat requests
• 5100–5199: Search/indexing
• 5200–5299: Image generation
• 5300–5399: Translation
• 5900–5999: Custom/generic

{
  "kind": 5100,
  "content": "",
  "tags": [
    ["i", "What is the weather in Tokyo?", "text"],
    ["param", "model", "claude-3"],
    ["param", "temperature", "0.7"],
    ["bid", "1000"],
    ["relays", "wss://relay.damus.io"],
    ["p", "<customer-pubkey>"]
  ]
}

§Job Result (Kind 6000–6999)

{
  "kind": 6100,
  "pubkey": "<dvm-provider-pubkey>",
  "content": "The weather in Tokyo is 22°C, partly cloudy.",
  "tags": [
    ["e", "<job-request-id>"],
    ["p", "<customer-pubkey>"],
    ["amount", "1000"],
    ["status", "success"]
  ]
}

§Job Feedback (Kind 7000)

{
  "kind": 7000,
  "content": "{\"rating\":4,\"comment\":\"Good, but slow\"}",
  "tags": [
    ["e", "<job-result-id>"],
    ["p", "<dvm-provider-pubkey>"],
    ["status", "paid"]
  ]
}

§Payment Flow

Two models:

§Pre-paid (bid on request)

["bid", "1000"]  // msats, included in job request

Provider checks payment before delivering. Requires NWC or pre-funded account.

§Post-paid (invoice in result)

["amount", "1000", "invoice", "lnbc..."]  // in job result

Customer pays invoice to unlock result. Content delivered when payment confirmed.

§NIP-89 Integration

DVM providers announce services with kind 31990:

{
  "kind": 31990,
  "content": "{\"name\":\"Text Summarizer\",\"about\":\"Summarizes long text\",\"picture\":\"https://...\"}",
  "tags": [
    ["d", "text-summarizer"],
    ["k", "5100"],
    ["t", "ai"],
    ["t", "summarization"]
  ]
}

The k tag links to the job request kind it handles.

§Provider Selection

1. Search relays: Subscribe to kind 31990 events
2. Check reputation: Read kind 7000 feedback
3. Check price: Look at past bid/amount patterns
4. Check capabilities: Read provider info

§Example Providers

§Building a DVM

Minimal DVM provider loop:

import asyncio, json
from nostr import Relay, Event

async def handle_job(event):
    # Parse job request
    input_text = [t[1] for t in event.tags if t[0] == "i"][0]
    customer = [t[1] for t in event.tags if t[0] == "p"][0]

    # Process
    result = process(input_text)

    # Publish result
    await relay.publish(Event(
        kind=6100,
        content=result,
        tags=[
            ["e", event.id],
            ["p", customer],
            ["amount", "1000"],
            ["status", "success"]
        ]
    ))

async def main():
    relay = Relay("wss://relay.damus.io")
    await relay.connect()
    await relay.subscribe({"kinds": [5100]})
    async for event in relay:
        if event.kind == 5100:
            await handle_job(event)

asyncio.run(main())

§Reputation System

Feedback is public and permanent. Bad providers are visible. Customers and providers build reputation on-chain.

Provider ranking factors:

• Success rate (% of status: success results)
• Average feedback rating
• Response time
• Price competitiveness
• Dispute resolution

This creates a self-policing marketplace without a central authority.