Kafka Events

19 producer topics across 6 categories and 3 consumer groups published to Amazon MSK Serverless.

Event Format: CloudEvents 1.0

All events follow the CloudEvents 1.0 specification. Events are partitioned by tenant_id and published to Amazon MSK Serverless. blockchain-svc is both a producer and consumer — it publishes blockchain events and consumes ticketing, user, and wallet events from other services.

Brokers

Environment	Broker	Auth
Staging	`boot-gpm4u49z.c2.kafka-serverless.us-east-1.amazonaws.com:9098`	`SASL/OAUTHBEARER (IAM)`
Production	`b-1.eventzr-msk-prod.ap-south-1.amazonaws.com:9098`	`SASL/OAUTHBEARER (IAM)`

Event Envelope

CloudEvents 1.0 envelopejson

{
  "specversion": "1.0",
  "type": "eventzr.blockchain.ticket.minted.v1",
  "source": "blockchain-svc",
  "id": "evt-550e8400-e29b-41d4-a716-446655440000",
  "time": "2026-02-28T12:00:00.000Z",
  "datacontenttype": "application/json",
  "subject": "tenant-uuid",
  "data": {
    "tenantId": "tenant-uuid",
    "ticketId": "ticket-uuid",
    "contractAddress": "0x1234...abcd",
    "tokenId": 42,
    "chainId": "POLYGON",
    "ownerAddress": "0xabcd...1234",
    "transactionHash": "0xdeadbeef...",
    "blockNumber": 12345678,
    "gasUsed": "21000",
    "costUsd": 0.002
  }
}

Producer Topics (19)

NFT Tickets4

Topic	Description
`eventzr.blockchain.ticket.minted.v1`	NFT ticket minted on-chain
`eventzr.blockchain.ticket.transferred.v1`	Ticket ownership transferred
`eventzr.blockchain.ticket.validated.v1`	Ticket validated at gate
`eventzr.blockchain.ticket.revoked.v1`	Ticket access revoked

POAP & Loyalty2

Topic	Description
`eventzr.blockchain.poap.minted.v1`	Proof of Attendance minted
`eventzr.blockchain.loyalty.tier_changed.v1`	User loyalty tier changed

Marketplace3

Topic	Description
`eventzr.blockchain.listing.created.v1`	Resale listing created
`eventzr.blockchain.listing.sold.v1`	Resale listing sold
`eventzr.blockchain.revenue.distributed.v1`	Revenue distributed to stakeholders

Smart Contracts2

Topic	Description
`eventzr.blockchain.contract.deployed.v1`	Smart contract deployed on-chain
`eventzr.blockchain.contract.events.v1`	Contract events (standalone producer)

Wristbands & Gas4

Topic	Description
`eventzr.blockchain.wristband.linked.v1`	NFC wristband linked to ticket
`eventzr.blockchain.wristband.tapped.v1`	NFC wristband tap event
`eventzr.blockchain.gas.sponsored.v1`	Gas-sponsored transaction executed
`eventzr.blockchain.gas.updated.v1`	Gas price update

Telemetry4

Topic	Description
`eventzr.blockchain.nft.events.v1`	NFT mint events
`eventzr.blockchain.transaction.events.v1`	Transaction confirmed
`eventzr.blockchain.quota.events.v1`	Quota exceeded events
`eventzr.kg.blockchain`	Knowledge Graph events for Neptune

Consumer Topics (3)

Consumer Groups

blockchain-svc consumes events from other services to trigger on-chain operations (e.g., minting tickets when purchased, updating loyalty tiers on subscription changes).

Topic	Consumer Group	Description
`ticketing-events`	`blockchain-svc-ticketing-consumer`	Ticket purchase/cancel from ticketing-svc
`user-events / billing-events`	`blockchain-svc-user-consumer`	Tier changes, subscription renewals
`wallet-events`	`blockchain-svc-wallet-consumer`	Wallet creation, balance updates