Cardano

Endpoint	https://rpc.lab.au.ro/cardano
Protocol	ogmios JSON-RPC 2.0 over HTTPS (POST)
Network	mainnet
Batch	✓

cardano-node has no native HTTP RPC — we expose ogmios, the standard JSON-RPC bridge to the node's local protocols. Methods are namespaced: queryNetwork/*, queryLedgerState/*, submitTransaction, evaluateTransaction.

Supported methods

Live-verified: queryNetwork/tip, queryNetwork/blockHeight, queryNetwork/startTime, queryLedgerState/epoch, queryLedgerState/protocolParameters, submitTransaction — plus the rest of ogmios' ledger-state queries (utxo, stakePools, rewardsProvenance, …).

Quick test

curl -X POST https://rpc.lab.au.ro/cardano \
  -H "apikey: $YOUR_API_KEY" -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","method":"queryNetwork/tip","id":1}'
# {"jsonrpc":"2.0","method":"queryNetwork/tip","result":{"slot":189706322,"id":"587075ff..."}}

SDK integration

ogmios responses are plain JSON-RPC — a fetch helper covers queries:

async function ogmios(method, params = {}) {
  const res = await fetch('https://rpc.lab.au.ro/cardano', {
    method: 'POST',
    headers: { apikey: process.env.YOUR_API_KEY, 'Content-Type': 'application/json' },
    body: JSON.stringify({ jsonrpc: '2.0', method, params, id: 1 })
  })
  const { result, error } = await res.json()
  if (error) throw new Error(`${error.code}: ${error.message}`)
  return result
}

console.log(await ogmios('queryNetwork/tip'))
console.log('epoch:', await ogmios('queryLedgerState/epoch'))

For transaction building use an offline library (e.g. @emurgo/cardano-serialization-lib or lucid-style builders), then:

await ogmios('submitTransaction', { transaction: { cbor: signedCborHex } })
// invalid CBOR is rejected with a structured ogmios error — nothing relays

Recipes

• Protocol parameters for fee calc — queryLedgerState/protocolParameters (cached 30 s class).
• UTxO lookup — queryLedgerState/utxo with { addresses: [...] }.

Limitations

• ogmios' chain-synchronization (streaming) protocol needs WebSockets — not available until our WS endpoint ships; ledger-state queries cover polling use cases.
• No Blockfrost-style indexed history (address→tx lists); UTxO and ledger state are current-tip views.