Connecting to the chain

Use the hosted c12-testnet-1 endpoints for integration. Public RPC and REST are served over HTTPS (fronted by Caddy). CORS is open on those public RPC and REST endpoints for browser dApps. gRPC is 52.6.69.73:9200 plaintext (no TLS for now). There are no published rate limits on RPC/REST/EVM yet; the faucet enforces 1 drip per address and per IP per 24 hours.

Endpoint table

Interface	URL / host	Default port (single-node template)
CometBFT RPC	https://rpc.testnet.carbon12.network	26657
Cosmos REST (LCD)	https://rest.testnet.carbon12.network	1317
EVM JSON-RPC	https://evm.testnet.carbon12.network	8545 (local); hosted path above
gRPC	52.6.69.73:9200	9090 (local template)
WebSocket	Comet /websocket on RPC URL	Same host as RPC

Local multi-node offsets are documented in devnet/scripts/lib.sh (REST 1317+i, gRPC 9090+i*10, EVM 8545+i*2).

CosmJS (TypeScript)

import { StargateClient } from "@cosmjs/stargate";

const rpc = "https://rpc.testnet.carbon12.network";
const client = await StargateClient.connect(rpc);
const height = await client.getHeight();
console.log("chain height", height);

Query LCD modules via fetch:

const rest = "https://rest.testnet.carbon12.network";
const res = await fetch(`${rest}/c12/registry/v1/schemas/list`);
const body = await res.json();

Message types and protobuf paths live under proto/c12/*/v1/ in the chain repo.

gRPC

Generated stubs come from chain make proto-gen. Example service paths used by tooling:

• /c12.aggregate.v1.Query/Proof
• Registry, attest, checking queries as defined in proto/c12/*/v1/query.proto

Plaintext gRPC to 52.6.69.73:9200 (no TLS for now). Do not send credentials over untrusted networks without a TLS front-end you control.

grpcurl -plaintext 52.6.69.73:9200 list

(grpcurl must be installed locally.)

EVM: ethers v6

import { JsonRpcProvider, Contract } from "ethers";

const provider = new JsonRpcProvider("https://evm.testnet.carbon12.network");
const network = await provider.getNetwork();
console.log(network.chainId); // 12121n

const IC12 = "0x0000000000000000000000000000000000000C12";
const abi = ["function head(string eventId) view returns (string recordId, uint8 status, uint32 revision)"];
const c12 = new Contract(IC12, abi, provider);

EVM: viem

import { createPublicClient, http } from "viem";

const client = createPublicClient({
  transport: http("https://evm.testnet.carbon12.network"),
});

const chainId = await client.getChainId(); // 12121

Configure a custom chain definition with id: 12121 for wallet clients.

CometBFT RPC & WebSocket

curl -s https://rpc.testnet.carbon12.network/status | jq .
curl -s "https://rpc.testnet.carbon12.network/block?height=1" | jq .

Subscribe to events via WebSocket at wss://rpc.testnet.carbon12.network/websocket (scheme/host follow your RPC deployment).

REST module paths (examples)

Module	Example
Oracle price	/c12/oracle/v1/price
Participants	/c12/registry/v1/participants/list
Schemas	/c12/registry/v1/schemas/list
Aggregate proof	/c12/aggregate/v1/proof?key=…
Tx by hash	/cosmos/tx/v1beta1/txs/{hash}

Explorer smoke script: scripts/chain-smoke.ts in the explorer repo.

CORS & rate limits

• CORS: Open on public CometBFT RPC and Cosmos REST (https://rpc.testnet.carbon12.network, https://rest.testnet.carbon12.network). Third-party explorers may still proxy REST (e.g. GET /api/lcd/* → C12_REST).
• Rate limits: None published yet for RPC/REST/EVM JSON-RPC. Abuse may be handled operationally; plan for client-side backoff.
• Faucet: 1 drip per address and per IP per 24h — see Testnet status.

Minimum gas price

Nodes default to 0.001uc12 (app/config/config.go). Wallets should set matching fee tokens on broadcast.