eth_newFilter - Ethereum
Creates a filter object, based on filter options, to notify when the state changes (logs).
Unlike eth_newBlockFilterwhich notifies you of all new blocks, you can pass in filter options to track new logs matching the topics specified.
To check if the state has changed, call eth_getFilterChanges
A note on specifying topic filters:
Topics are order-dependent. A transaction with a log with topics [A, B] will be matched by the following topic filters:
  • [] “anything”
  • [A] “A in first position (and anything after)”
  • [null, B] “anything in first position AND B in second position (and anything after)”
  • [A, B] “A in first position AND B in second position (and anything after)”
  • [[A, B], [A, B]] “(A OR B) in first position AND (A OR B) in second position (and anything after)”

Parameters

  • Object - The filter options:
    1. 1.
      fromBlock: QUANTITY|TAG - (optional, default: "latest") Integer block number, or "latest" for the last mined block or "pending", "earliest" for not yet mined transactions.
    2. 2.
      toBlock: QUANTITY|TAG - (optional, default: "latest") Integer block number, or "latest" for the last mined block or "pending", "earliest" for not yet mined transactions.
    3. 3.
      address: DATA|Array, 20 Bytes - (optional) Contract address or a list of addresses from which logs should originate.
    4. 4.
      topics: Array of DATA, - (optional) Array of 32 Bytes DATA topics. Topics are order-dependent. Each topic can also be an array of DATA with “or” options.
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params: [{
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"fromBlock": "0x1",
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"toBlock": "0x2",
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"address": "0x8888f1f195afa192cfee860698584c030f4c9db1",
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"topics": ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", null, ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", "0x0000000000000000000000000aff3454fce5edbc8cca8697c15331677e6ebccc"]]
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}]
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Returns

QUANTITY - A filter id.

Example

Request
Curl
Postman
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curl https://eth-mainnet.alchemyapi.io/v2/your-api-key \
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-X POST \
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-H "Content-Type: application/json" \
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-d '{"jsonrpc":"2.0","method":"eth_newFilter","params":[{"fromBlock": "0x1","toBlock": "0x2","address": "0x8888f1f195afa192cfee860698584c030f4c9db1","topics": ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", null, ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", "0x0000000000000000000000000aff3454fce5edbc8cca8697c15331677e6ebccc"]]}],"id":0}'
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URL: https://eth-mainnet.alchemyapi.io/v2/your-api-key
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RequestType: POST
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Body:
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{
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"jsonrpc":"2.0",
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"method":"eth_newFilter",
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"params":[{"fromBlock": "0x1","toBlock": "0x2","address": "0x8888f1f195afa192cfee860698584c030f4c9db1","topics": ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", null, ["0x000000000000000000000000a94f5374fce5edbc8e2a8697c15331677e6ebf0b", "0x0000000000000000000000000aff3454fce5edbc8cca8697c15331677e6ebccc"]]}],
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"id":0
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}
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Result
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{
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"jsonrpc": "2.0",
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"id": 0,
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"result": "0xdcc9a819f80efa9e1d215a9d41b2d22e"
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}
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Alchemy Documentation
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