eth_syncing

eth_syncing reports whether a Polygon PoS node is still catching up to the chain head. It returns false when the node is fully synced and serving current data, or an object with startingBlock, currentBlock, and highestBlock while it is still importing blocks. Because Polygon produces a block roughly every 2 seconds, a node that has fallen behind can lag by a large number of blocks quickly, so this check matters before you trust any balance or MATIC transaction it returns. Query it against the Polygon mainnet endpoint at https://polygon.therpc.io/YOUR_API_KEY (chain ID 137, 0x89) to confirm the node backing your requests is current.

Use cases

• Verify a freshly started Polygon Bor node has caught up to the head before routing production traffic to it.
• Compute a sync progress percentage from currentBlock and highestBlock to drive a node-monitoring dashboard.
• Gate application startup so your dApp does not begin reading USDT balances or QuickSwap state until the node is fully synced.
• Diagnose a stuck or slow node by polling currentBlock over time — on a healthy Polygon node it should advance by roughly one block every 2 seconds.

Parameters

此方法不需要任何参数，传入空数组 [] 即可。

Response

Example request

1curl https://polygon.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H "Content-Type: application/json" \
4  -d '{
5    "jsonrpc": "2.0",
6    "method": "eth_syncing",
7    "params": [],
8    "id": 1
9  }'

Try it live in the Polygon playground.

Errors & troubleshooting

Common pitfalls

• Some clients can return false during specific sync phases even when not fully caught up — do not treat false as an absolute guarantee; cross-check currentBlock against the expected head if correctness is critical.
• On Polygon this reports the Bor execution-layer sync only. Heimdall, the Tendermint-based consensus layer that drives validator selection and L1 checkpoints, has its own separate status endpoint and is not covered here.
• The returned object's shape varies by client implementation, so code that reads extra progress fields beyond the three standard keys should handle missing keys gracefully.

Supported networks

• Mainnet — Chain ID: 137
• Amoy — Chain ID: 80002

See also

• eth_blockNumber
• eth_chainId
• net_peerCount

1curl https://polygon.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H 'Content-Type: application/json' \
4  -d '{"jsonrpc":"2.0","id":1,"method":"eth_syncing","params":[]}'