eth_getFilterChanges

BNB Smart Chain settles BNB-denominated transactions into blocks roughly every three seconds, so a stateless application needs an efficient way to ask "what is new?" eth_getFilterChanges does exactly that: hand it a filter ID and it returns only the events that arrived since your previous call, advancing an internal cursor each time. The payload type follows the filter — log objects for a log filter, block-hash strings for a block filter, or transaction-hash strings for a pending filter. Direct the poll at https://bsc.therpc.io/YOUR_API_KEY on chain ID 56 to keep an indexer current without re-sending the filter criteria.

Use cases

Pull fresh BEP-20 or PancakeSwap log events on a short interval while the heavy filter definition stays server-side.
Run a block-tick loop on chain 56: register an eth_newBlockFilter once, then call this method on repeat to learn of each newly sealed block.

Parameters

#	Name	Type	Required	Description
1	`filterId`	string	Yes	The filter ID to poll.

Response

Type	Description
array	For log filters: array of log objects. For block filters: array of block hash strings. For pending-tx filters: array of transaction hash strings. Empty array if no new events.

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_getFilterChanges",
7    "params": ["0x1"],
8    "id": 1
9  }'

Try it live in the BNB Smart Chain playground.

Errors & troubleshooting

Code	Message	Cause
`-32000`	`filter not found`	Filter ID is invalid, expired (>5 min inactivity), or was already uninstalled.

Common pitfalls

A node forgets an idle filter after about five minutes, so catch the filter-not-found error and transparently rebuild the filter before resuming the loop.
When the filter emits logs, read the removed flag on each one to catch entries rolled back by a BSC reorg and undo them downstream.
There is a balance to strike: calling too often wastes compute units on empty arrays, while waiting too long lets the filter expire out from under you.

Supported networks

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