monitoring

STOM

Starknet on-chain monitoring (STOM) polls OCR2 aggregator and token contracts via JSON-RPC and exports Prometheus metrics.

Starknet v0.14.3 / RPC requirements

Starknet v0.14.3 (Sepolia: June 2026, Mainnet: June 2026) deprecates RPC 0.8 and renames the "pending" block tag to "pre_confirmed".

STOM requires an RPC 0.9 or 0.10.x endpoint (e.g. .../rpc/v0_10). RPC 0.8 URLs will fail after network activation. Self-hosted nodes should run Pathfinder ≥ v0.22.4.

Block tags used by STOM

STOM is read-only. Contract view calls (starknet_call for latest_round_data, link_available_for_payment, ERC20 balance_of, etc.) use the latest block tag — the most recent block finalized by L2 consensus. This keeps metrics stable and aligned with finalized on-chain state.

The relayer TXM (transaction manager) uses pre_confirmed separately for nonce lookup and fee estimation, where in-flight transaction state is required. STOM does not use those code paths.

Event queries use a block number when available, and only fall back to pre_confirmed when fetching events for a block that is still ahead of the chain tip.

Useful links

• Starknet on-chain monitor generated docs.
• On-chain monitoring (OM) framework architecture docs in blueprints.
• OM framework generated docs.

Local development

Note: Previously, this monitor also wrote to Kafka, but the dependency on Kafka has been removed in order to simplify deployment. The kafka topics were unused anyway.

• Start an http server that mimics weiwatchers locally. It needs to export a json configuration file for feeds:

[
  {
    "name": "LINK / USD",
    "path": "link-usd",
    "symbol": "$",
    "heartbeat": 0,
    "contract_type": "numerical_median_feed",
    "status": "testing",
    "contract_address": "<CONTRACT_ADDRESS>",
    "multiply": "100000000",
    "proxy_address": "<PROXY_ADDRESS>"
  }
]

It also needs to export a json configuration for for node operators:

[
  {
    "id": "noop",
    "nodeAddress": [<NODE_OPERATOR_ADDRESS>]
  }
]

One option is to create a folder /tmp/configs and add two files feeds.json and nodes.json with the configs from above, then:

python3 -m http.server 4000

• Start STOM locally. You will need an RPC 0.9 or 0.10.x endpoint (e.g. .../rpc/v0_10) and the address of the LINK token. Make sure you cd ./monitoring.

STARKNET_RPC_ENDPOINT="<RPC_ENDPOINT>" \
STARKNET_NETWORK_NAME="devnet" \
STARKNET_NETWORK_ID="1" \
STARKNET_CHAIN_ID="1" \
STARKNET_READ_TIMEOUT="5s" \
STARKNET_POLL_INTERVAL="10s" #test \
STARKNET_LINK_TOKEN_ADDRESS="<LINK_TOKEN_ADDRESS>" \
HTTP_ADDRESS="localhost:3000" \
FEEDS_URL="http://localhost:4000/feeds.json" \
NODES_URL="http://localhost:4000/nodes.json" \
go run ./cmd/monitoring/main.go

• Check the output for the Prometheus scraper

curl http://localhost:3000/metrics