API

JSON-RPC API

Both Starknet's and Devnet's JSON-RPC API are reachable at /rpc and /. E.g. if spawning Devnet with default settings, these URLs are functionally equivalent: http://127.0.0.1:5050/rpc and http://127.0.0.1:5050/. The difference between these two groups of methods is their prefix: starknet_ (e.g. starknet_getNonce) and devnet_ (e.g. devnet_mint).

Starknet API

Unlike Pythonic Devnet, which also supported Starknet's gateway and feeder gateway API, Devnet in Rust supports Starknet's JSON-RPC API, including WebSocket support.

Due to how Devnet internally works, the method starknet_getStorageProof is not applicable, and thus not supported.

Devnet also provides a proof-related extension method starknet_proveTransaction. For supported modes, behavior, and usage examples, check Transaction proofs and proof modes.

Since JSON-RPC v0.6.0, to find out which JSON-RPC version is supported by which Devnet version, check out the releases page.

Local transaction statuses

Locally submitted transactions execute during submission. Their finality status depends on the block-generation mode:

Mode	Status when submission succeeds	Status after block creation
transaction (default)	ACCEPTED_ON_L2	ACCEPTED_ON_L2
demand or a numeric interval	PRE_CONFIRMED	ACCEPTED_ON_L2

Local transactions never enter RECEIVED or CANDIDATE. A validation failure returns an error without retaining a transaction. An executed transaction can have execution status SUCCEEDED or REVERTED; this is independent of its finality status. ACCEPTED_ON_L1 is available through the explicit L1 acceptance simulation.

starknet_getTransactionStatus, transaction receipts, and transaction-status WebSocket notifications report these executed statuses. An unknown or removed local transaction hash returns TXN_HASH_NOT_FOUND (code 29) from starknet_getTransactionStatus. Snapshot restoration can return a retained transaction to its earlier status. In forking mode, responses forwarded to the origin reflect that origin's behavior.

Devnet API

Devnet has many additional features available via JSON-RPC. The RPC methods are documented throughout the documentation in their corresponding pages, but are also aggregated here.

Use devnet_applyStateDiff to prepare chain state directly, including storage, nonces, declarations, deployments, and class replacements.

Healthcheck

To check if a Devnet instance is alive, send an HTTP request GET /is_alive. If alive, Devnet will reply with a 200 OK and an appropriate message. The optional embedded UI and metrics server also use HTTP endpoints outside the JSON-RPC API.

WebSocket

The whole Starknet and Devnet JSON-RPC API, including WebSocket subscription methods can be accessed via the WebSocket protocol, using text or binary messages. Devnet listens for new WebSocket connections at ws://<HOST>:<PORT>/ws (notice the protocol scheme). E.g. using wscat on the same computer where Devnet is spawned at default host and port:

$ wscat -c ws://127.0.0.1:5050/ws
Connected (press CTRL+C to quit)
> { "jsonrpc": "2.0", "id": 0, "method": "starknet_subscribeNewHeads" }
< {"id":0,"result":"2935616350010920547","jsonrpc":"2.0"}

WebSocket persistence

Restarting and loading do not affect Devnet's WebSocket connections, but remove all subscriptions. Snapshot restoration preserves subscriptions and sends notifications for restored state.

Interacting with Devnet in JavaScript and TypeScript

To spawn Devnet and interact with it using the Devnet API, you can use starknet-devnet-js. This can be especially useful in achieving L1-L2 communication.

To interact with Devnet using the Starknet API, use starknet.js.

Config API

Send devnet_getConfig to retrieve the resolved startup configuration, including explicit CLI or environment settings and defaults. Use starknet-devnet --help to interpret the fields; some field names differ from their CLI options. Runtime changes made by methods such as devnet_setGasPrice, devnet_setTime, impersonation, or snapshot restoration do not update this response. Use devnet_getStatus for a summary of runtime state and block queries for gas prices currently in effect.

For example, starting with starknet-devnet --seed 42 --accounts 2 --host 127.0.0.1 --block-generation-on demand --dump-on request --state-archive-capacity full returns the following result. Class hashes and defaults may change between versions.

{
  "seed": 42,
  "total_accounts": 2,
  "account_contract_class_hash": "0x5b4b537eaa2399e3aa99c4e2e0208ebd6c71bc1467938cd52c798c601e43564",
  "predeployed_accounts_initial_balance": "1000000000000000000000",
  "start_time": null,
  "gas_price_wei": 1000000000,
  "gas_price_fri": 1000000000,
  "data_gas_price_wei": 1000000000,
  "data_gas_price_fri": 1000000000,
  "l2_gas_price_wei": 1000000000,
  "l2_gas_price_fri": 1000000000,
  "chain_id": "SN_SEPOLIA",
  "dump_on": "request",
  "dump_path": null,
  "block_generation_on": "demand",
  "lite_mode": false,
  "proof_mode": "devnet",
  "state_archive": "full",
  "fork_config": {
    "url": null,
    "block_number": null,
    "caching_enabled": null
  },
  "eth_erc20_class_hash": "0xb45dbc3714180381c5680e41931172d67194d77d504413465390e0bef194ec",
  "strk_erc20_class_hash": "0x2e77ee61d4df3d988ee1f42ea5442e913862cc82c2584d212ecda76666498fc",
  "class_size_config": {
    "maximum_contract_class_size": 4089446,
    "maximum_contract_bytecode_size": 81920,
    "maximum_sierra_length": 81920
  },
  "server_config": {
    "host": "127.0.0.1",
    "port": 5050,
    "timeout": 120,
    "restricted_methods": null,
    "ui_enabled": false
  }
}

Status API

To retrieve a summary of the current Devnet state (block count, transaction count, forking info, impersonation state, etc.), send a JSON-RPC request with method name devnet_getStatus. This method takes no parameters and is useful for dashboards or monitoring tools.

{
  "jsonrpc": "2.0",
  "id": "1",
  "method": "devnet_getStatus"
}

The protocol_version field reports the JSON-RPC specification version, while devnet_version reports the version of the running Devnet package. block_count counts retained local accepted blocks, including genesis; transaction_count also includes pre-confirmed transactions. fork_config is present only when forking and uses the fields url and block.

For the startup command shown above, the initial result is:

{
  "block_count": 1,
  "transaction_count": 0,
  "pre_confirmed_tx_count": 0,
  "chain_id": "SN_SEPOLIA",
  "protocol_version": "0.10.2",
  "devnet_version": "0.10.1",
  "is_forked": false,
  "impersonated_accounts": [],
  "auto_impersonate": false
}