Join the testnet and mainnet network using Node Snapshots

⚠️

Before you resync a node using snapshots, make sure that in case of a successfull resync that you under no circumstance cannot double sign blocks at previous heights with your validator. Failure to do so will cause tombstoning of your validator.

Follow this guide to join an existing network through snapshot sync. To quickly spin up a fresh full node and join the network, it’s recommended to restore from a snapshot instead of replaying all historical blocks.

Snapshot Sync

Snapshot sync allows a new node to join a network by downloading a recent, compressed copy of the entire application state (including the wasm folder) and extracting it directly into the data directory. This reduces the initial sync time from days to minutes.

Two community‑maintained sources provide reliable snapshots:

Polkachu periodic snapshots – lightweight node snapshots for both mainnet and testnet, published several times a day.
CryptoCrew full archive snapshots – complete, genesis‑to‑tip archives for operators who need the full transaction history.

Choose the option that best fits your storage and indexing needs.

Clean Up

If you are not starting a node from fresh, perform the following backups and clean‑ups first.

Note: This step is not needed for fresh nodes.

Assuming your sei home directory is $HOME/.sei, back up priv_validator_key.json and priv_validator_state.json:


cp $HOME/.sei/data/priv_validator_state.json $HOME/priv_validator_state.json
cp $HOME/.sei/config/priv_validator_key.json $HOME/priv_validator_key.json

Reset the state:


seid tendermint unsafe-reset-all --home $HOME/.sei --keep-addr-book

Finally, remove the existing data and wasm folders and restore the priv_validator_state.json:


rm -rf $HOME/.sei/data/\*
rm -rf $HOME/.sei/wasm
cp $HOME/priv_validator_state.json $HOME/.sei/data/priv_validator_state.json

Download & Restore a Snapshot

Option 1 — Polkachu (recommended for most operators)

Prerequisites


sudo apt install lz4 wget

Stop the daemon


sudo systemctl stop seid

Download and extract snapshot

First, get the latest snapshot height from Polkachu:

Mainnet: Polkachu Mainnet Snapshots
Testnet: Polkachu Testnet Snapshots

Set the HEIGHT variable with the latest snapshot height:


HEIGHT=<LATEST_HEIGHT_FROM_POLKACHU>

Then set the snapshot URL based on your network:

For Mainnet:


SNAP_URL="https://snapshots.polkachu.com/snapshots/sei/sei_${HEIGHT}.tar.lz4"

For Testnet:


SNAP_URL="https://snapshots.polkachu.com/testnet-snapshots/sei/sei_${HEIGHT}.tar.lz4"

Download & extract:


wget -O sei_snapshot.tar.lz4 $SNAP_URL --inet4-only
lz4 -c -d sei_snapshot.tar.lz4 | tar -x -C $HOME/.sei

Restore validator state if you backed it up:


cp $HOME/.sei/priv_validator_state.json $HOME/.sei/data/priv_validator_state.json

Restart the daemon:


sudo systemctl start seid

Optional: Remove the snapshot file


rm sei_snapshot.tar.lz4

Option 2 — CryptoCrew Full Archive

Prerequisites


sudo apt install wget lz4

Stop the daemon


sudo systemctl stop seid

Download and stream extract

Find the latest archive from Cryptocrew here and find the height of the snapshot that you want to sync to: https://github.com/cryptocrew-validators/CryptoCrew-Validators/blob/main/chains/sei/service_Archive_Snapshot.md

Set this height as parameter:


height=<HEIGHT_NUMBER>

Then, set your ARCH:


ARCH_URL="https://dl-eu2.ccvalidators.com/SNAPSHOTS/archive/sei/pacific-1_${height}.tar.lz4"


rm -rf $HOME/.sei/data
rm -rf $HOME/.sei/wasm
rm -rf $HOME/.sei/config/priv_validator_key.json

Stream‑extract the archive to save disk space:


wget -O - $ARCH_URL | lz4 -d | tar -xvf -

Restore validator state file:


rm data/priv_validator_state.json
mv ./priv_validator_state.json.tmp data/priv_validator_state.json

Restart the daemon:


sudo systemctl start seid

Both methods leave you with a fully‑synced node in minutes. Verify the node is catching up (journalctl -fu seid -o cat) and compare the reported block height against a public RPC endpoint or a block explorer.

Troubleshooting snapshots

Q: I can’t download a snapshot.

A: Try another time later as these snapshots are refreshed regularly and inform us in the Sei Tech Chat

Q: The snapshot finishes, but immediately get AppHash errors upon regular block sycing:

A: Make sure that you use the latest version of the node software.