Setup fabconnect middleware
Setup fabric API layer
Summary
To enable API-based interaction with your Fabric smart contracts, the first step is to configure FabConnect middleware. This component exposes REST and WebSocket endpoints that allow you to submit transactions, query chaincode, retrieve blocks, and manage events programmatically.
Once FabConnect is added to your application, you gain full access to the underlying blockchain network through structured HTTP calls. You can register and manage identities via Fabric CA, monitor ledger state, submit transactions in sync or async mode, and configure event listeners for real-time responses.
How to setup graph middleware and api portal in SettleMint platform
Middleware acts as a bridge between your blockchain network and applications, providing essential services like data indexing, API access, and event monitoring. Before adding middleware, ensure you have an application and blockchain node in place.
How to add middleware
Firefly fabconnect api reference overview
This reference outlines the key API endpoints exposed by Hyperledger FireFly FabConnect, a REST and WebSocket gateway that enables interaction with Hyperledger Fabric networks via structured HTTP requests and event subscriptions.
Authentication & setup
| Field | Description |
|---|---|
| Auth Type | Bearer Token (JWT) |
| Header | Authorization: Bearer <your_token> |
| Base URL | https://fabconnect-34253.gke-europe.settlemint.com |
Identity management
Manage user identities through Fabric CA:
| Endpoint | Method | Description |
|---|---|---|
/identities | GET | List all registered identities |
/identities | POST | Register a new identity with the CA |
/identities/{username} | GET | Get details of a specific identity |
/identities/{username} | PUT | Modify existing identity’s attributes |
/identities/{username}/enroll | POST | Enroll the identity to receive certificates |
/identities/{username}/reenroll | POST | Re-enroll the identity to renew certificates |
/identities/{username}/revoke | POST | Revoke the identity’s certificates |
Ledger & block info
Fetch metadata and raw data from the Fabric blockchain:
| Endpoint | Method | Description |
|---|---|---|
/chaininfo | GET | Get current block height and hashes for a channel |
/blocks/{blockNumberOrHash} | GET | Retrieve block by number or hash |
/blockByTxId/{txId} | GET | Retrieve block that contains a specific transaction |
Transaction handling
Submit transactions or check transaction state:
| Endpoint | Method | Description |
|---|---|---|
/transactions | POST | Submit a transaction (sync or async) |
/transactions/{txId} | GET | Fetch transaction details using transaction ID (hash) |
Chaincode queries
Execute read-only chaincode function calls:
| Endpoint | Method | Description |
|---|---|---|
/query | POST | Send a query request to chaincode |
Transaction receipts (for async mode)
Access receipts from async transaction submissions (fly-sync=false):
| Endpoint | Method | Description |
|---|---|---|
/receipts | GET | List available transaction receipts |
/receipts/{receiptId} | GET | Get a specific receipt by ID |
Event streams
Create and manage WebSocket or Webhook-based event delivery pipelines:
| Endpoint | Method | Description |
|---|---|---|
/eventstreams | GET | List all existing event streams |
/eventstreams | POST | Create a new event stream |
/eventstreams/{eventstreamId} | GET | Retrieve a specific event stream |
/eventstreams/{eventstreamId} | DELETE | Delete a specific event stream |
Event subscriptions
Configure event listening rules on chaincode or block events:
| Endpoint | Method | Description |
|---|---|---|
/subscriptions | GET | List all subscriptions |
/subscriptions | POST | Create a new subscription |
/subscriptions/{subscriptionId} | GET | Get a specific subscription by ID |
/subscriptions/{subscriptionId} | DELETE | Remove a subscription by ID |
Advanced controls
| Feature | Details |
|---|---|
Sync Mode (fly-sync) | Use true for synchronous (wait for commit), false for async |
| Custom Channel | Override with fly-channel parameter in query |
| Signer Identity | Use fly-signer to choose which identity signs the request |
| Schema Support | Structured mode supports input validation using JSON schema headers |
Congratulations.!!
You have succesfully configured Fabconncet middleware and have API access on your chaincode.
From here we will proceed to adding off-chain database and storage options to enable us to have a holistic backend and storage layer for our application.