Relations of an address at a block

Open the USDC contract in TraceFast →

The relations an address was the subject of at the end of one block — which implementation a proxy pointed at, which beacon it read, who administered it, where an account had delegated — each with the window of blocks it held for.

GET https://tracefast.xyz/api/v1/chains/1/entities/{address}/relations/at-block?block={block}

Parameter	In	Type	Notes
`address`	path	string	`0x`-prefixed, 40 hex characters, any case
`block`	query	integer, required	the block to answer about — the state at the end of it

Access — an API key on the Intelligence plan or higher (plans), or no key at all: pay per call with x402 at the same path on https://mpp.tracefast.xyz/api/v1, at the price its 402 states. As a tool for AI agents: get_entity_relations_at_block on the MCP server. Stable — see stability.

chains/1 is a literal: other chain ids answer 404 chain_not_supported. An unknown parameter is refused rather than ignored.

What it covers, and what it does not

The subject side only. The answer is always "what did this address point at". There is no direction parameter. For "who pointed at it", use the relation history with direction=object.
Only the relation ids in coveredFamilies. A relation outside that list is not listed whether or not it held. The current relations cover more ids than the history does.
Absence means "not proven", never "false".
A block past the covered history is refused with the highest block that can be answered.

Response

200 application/json for the USDC proxy, here with ?block=20000000:

{
  "data": {
    "chainId": 1,
    "address": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
    "block": 20000000,
    "coverageBlock": 25924843,
    "addressKnown": true,
    "intervals": [
      {
        "attributeId": "relation:was_implementation_of",
        "counterpart": "0x43506849d7c04f9138d1a2050bbf3a0c054402dd",
        "startBlock": 18963716
      }
    ],
    "coveredFamilies": [
      "relation:was_implementation_of",
      "relation:eip7702_delegates_to",
      "relation:proxy_reads_beacon",
      "relation:proxy_administered_by",
      "relation:freeze_membership"
    ]
  },
  "meta": {
    "chain": "ethereum",
    "timestamp": 1789047687092,
    "cached": false,
    "asOfBlock": 25924843,
    "docs": "https://docs.tracefast.xyz/api/address-relations-at-block"
  }
}

At block 20,000,000 the USDC proxy pointed at the implementation 0x4350…02dd, which it has used since block 18,963,716. The interval has no endBlock: it was still open at the end of the covered history.

`data`

Field	Meaning
`chainId`	`1`, Ethereum mainnet
`address`	the address, lowercase — always the subject of the relations listed
`block`	the block you asked about, echoed
`coverageBlock`	the highest block the history has been computed up to
`addressKnown`	`false` when the history does not know the address at all — a different answer from an empty `intervals`. Absent when the history does not state it
`intervals[]`	the relations that held at `block`, each with its window
`coveredFamilies`	the relation ids the history is built for

An interval

Field	Meaning
`attributeId`	the relation id, `relation:name`
`counterpart`	the object of the relation, lowercase
`startBlock`	the first block the relation held at
`endBlock`	the last block it held at. Absent when the interval was still open at the end of the covered history
`value`	the relation's value over the interval, for relations that carry one; absent otherwise

Errors

Status	`code`	When	`details`
400	`bad_request`	`block` absent	`reason: block_required`
400	`bad_request`	`block` is `0` or not a number	`reason: block_not_positive`, `block`
422	`block_not_available`	`block` is past the covered history	`reason: block_not_available`, `maxAvailableBlock`

Malformed input, unknown parameters and the key check's 401/403/429 are the same for every method — see conventions and API keys.

Relations of an address — the relations that hold now, from either side
Relation history of an address — every interval, in either direction
Implementations of a proxy contract — a proxy's implementation timeline
Attributes of an address at a block — the same question for attributes

Last updated 22 Oct 2026, 08:06 UTC · verified against TraceFast v1.0.261 · Markdown