eth_syncing

BNB Smart Chain mints a block roughly every three seconds under Proof-of-Staked-Authority consensus, settling BNB transfers and BEP-20 token activity. A node has to keep pace with that head or it falls behind. eth_syncing tells you which side of the line a given node sits on. Point your client at https://bsc.therpc.io/YOUR_API_KEY against chain ID 56 and the call comes back in one of two shapes. A fully caught-up node answers with a flat false. A node still replaying history answers with a progress object that carries startingBlock, currentBlock, and highestBlock.

Use cases

Confirm a freshly bootstrapped BSC archive or full node has finished importing before you route production traffic to it.
Render a sync-progress percentage in a node-monitoring dashboard by dividing currentBlock against highestBlock.
Gate application startup so a service refuses to serve requests until the underlying node reports false.
Diagnose a stalled or lagging validator-tracking node by polling currentBlock over successive three-second intervals and watching whether it advances.

Parameters

This method takes no parameters. Pass an empty array [].

Response

Type	Description
boolean \| object	false when the node is fully synced. When syncing, returns an object with at minimum: startingBlock (hex), currentBlock (hex), highestBlock (hex). Additional fields vary by client (e.g. Geth includes snap-sync progress counters; Erigon includes syncStage/syncProgress).

Example request

1curl https://bsc.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 BNB Smart Chain playground.

Errors & troubleshooting

Code	Message	Cause
`-32603`	`Internal error`	Node cannot determine sync state (e.g. no peers connected).

Common pitfalls

Certain clients briefly report false during specific sync phases even before they are truly caught up, so never treat a single false as proof the node holds the latest BNB Smart Chain head.
Because BSC folds validation and ordering into one PoSA execution layer, this call describes execution-layer import only; it does not surface any separate beacon or attestation status.
The progress object's extra fields are geth-family client specific, so code reading anything beyond the three guaranteed keys must tolerate missing entries without throwing.

Supported networks

Mainnet — Chain ID: 56
Testnet — Chain ID: 97