eth_getTransactionByBlockNumberAndIndex

eth_getTransactionByBlockNumberAndIndex returns one transaction from Polygon PoS (chain ID 137) addressed by a block — given as a height or a tag like latest or pending — plus the zero-based index of the transaction within it. Polygon's MATIC-fee, EVM-equivalent design and ~2-second Bor blocks make this handy for sequential scanning when you are iterating by block number rather than resolving block hashes first. Point the request at https://polygon.therpc.io/YOUR_API_KEY and it returns the same transaction object as eth_getTransactionByHash, or null if the block or index is out of range.

Use cases

• Iterate block-by-block over the first transaction (index 0x0) of each Polygon block for MEV and ordering research.
• Peek at a transaction in the next block by its position using the pending tag while Bor is still assembling it.
• Scan sequentially across a range of block numbers when you already have heights and do not need to resolve block hashes first.

Parameters

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_getTransactionByBlockNumberAndIndex",
7    "params": [
8        "latest",
9        "0x0"
10      ],
11    "id": 1
12  }'

Try it live in the Polygon playground.

Errors & troubleshooting

Common pitfalls

• The index is hex-encoded — pass "0x0", not the integer 0, for the first transaction.
• Results under the pending tag are not stable: which transactions appear and in what order depends on the node's current Bor mempool view and can differ between clients and between calls.

Supported networks

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

See also

• eth_getTransactionByBlockHashAndIndex
• eth_getTransactionByHash
• eth_getBlockByNumber

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_getTransactionByBlockNumberAndIndex","params":["",""]}'