Espresso Decaf

type:

testnet

chain id:

912559

install guide
monitoring
security hardening
contributions

Espresso Decaf Testnet — Node and Validator Setup

Decaf is Espresso's persistent testnet, used to rehearse integrations and node setups before mainnet. Every command and environment variable is identical to mainnet — only the L1, contract addresses, endpoints and genesis file differ.

Follow the full procedure in the Espresso node and validator guide, then substitute the values below. Monitoring and hardening are unchanged:

Verified against the official operator documentation on 2026-09-16.

Decaf values

	Decaf testnet
L1	Ethereum Sepolia
Container image	`ghcr.io/espressosystems/espresso-network/espresso-node:20260910`
Genesis file	`/genesis/decaf.toml`
Stake table contract	`0x40304fbe94d5e7d1492dd90c53a2d63e8506a037`
Query service	`https://query.decaf.testnet.espresso.network`
Config cache	`https://cache.decaf.testnet.espresso.network`
State relay	`https://state-relay.decaf.testnet.espresso.network`
Block explorer	`https://explorer.decaf.testnet.espresso.network`
Staking UI	`https://stake.decaf.espresso.network/`

Sepolia contracts

Contract	Address
Stake Table	`0x40304fbe94d5e7d1492dd90c53a2d63e8506a037`
ESP Token	`0xb3e655a030e2e34a18b72757b40be086a8f43f3b`
Reward Claim	`0xe81908e34dbb4ba01f27f8769264199727be50c8`
Light Client	`0x303872bb82a191771321d4828888920100d0b3e4`

Environment differences


ESPRESSO_NODE_GENESIS_FILE=/genesis/decaf.toml
ESPRESSO_STATE_RELAY_SERVER_URL=https://state-relay.decaf.testnet.espresso.network
ESPRESSO_NODE_STATE_PEERS=https://query.decaf.testnet.espresso.network
ESPRESSO_NODE_API_PEERS=https://query.decaf.testnet.espresso.network

# First start only:
ESPRESSO_NODE_CONFIG_PEERS=https://cache.decaf.testnet.espresso.network

# Sepolia, not Ethereum mainnet:
ESPRESSO_L1_PROVIDER=https://<your-sepolia-rpc>
ESPRESSO_L1_WS_PROVIDER=wss://<your-sepolia-ws-rpc>

staking-cli takes --network decaf wherever the mainnet guide uses --network mainnet, and STAKE_TABLE_ADDRESS becomes the Sepolia address above.

Getting a delegation

Decaf ESP is not publicly distributed. A registered Decaf node stays out of consensus until the Espresso team delegates to it.

Register the validator and start the node, exactly as on mainnet.
Confirm it is registered and reachable: staking-cli --network decaf stake-table-entry --address $VALIDATOR_ADDRESS.
Ask for a delegation in #decaf-node-ops on the Espresso Discord.

The node joins consensus once that delegation is active — 2 epochs after the Sepolia transaction finalizes.

What Decaf is good for

Rehearse anything you would not want to get wrong on mainnet with real ESP:

register-validator and the exact metadata document;
update-consensus-keys and the third-epoch activation window;
update-network-config after moving the node to a new host or DNS name;
deregister-validator → claim-validator-exit and the ~7-day escrow;
unclaimed-rewards / claim-rewards against a query service;
the whole monitoring and alerting stack, before it matters.

Sepolia gas is free; mainnet mistakes are not.

Official resources

Run a Validator Node: https://docs.espressosys.com/network/developer/operators/run-a-node
Networks & contracts: https://docs.espressosys.com/network/network/networks
Discord: https://discord.gg/espresso