Full analysis selected. Choose Quick brief to read the key points first.
WFN QUICK BRIEF · UNDER 1 MIN
The short version
MODE 2 OF 2
What the primary record establishes
ERC-165 has Final status and defines supportsInterface(bytes4). Its interface identifiers are formed from the XOR of function selectors. The detection procedure checks support for ERC-165 itself and requires the invalid identifier 0xffffffff to return false. ERC-165 — Standard Interface Detection, Final specification ↗
What the distinction changes
WFN’s interpretation is that a positive response can guide integration, but it cannot establish sound economics, safe permissions or the absence of implementation defects. Those are different assessments.
What to check before drawing a conclusion
Retain the network, contract address, queried identifier and block reference in a compatibility test. A label in a product page is less specific than the response from the actual deployed contract.
Quick Brief is a reading aid. The full article and source trail stay on this page.
WFN STORY COMPASS
Choose your reading angle
Switch between the reported record, market context and open questions. Status labels distinguish claims from findings.
All context layers are visible. Choose a lens to jump to that part of the story.
Original WFN vector illustrationWFN · 22 October 2026
Editorial noteSource-based explanation with original WFN analysis. Historical records retain their dates; numerical examples are illustrative. The original vector illustration is conceptual and is not documentary evidence.
WFN REALITY LEDGER
What is on the record?
Primary-source explainer
Primary-source explainer
Primary record / reference periodFinal interface-detection standard checked 22 October 2026
The linked source supports the documented record; WFN interpretation and illustrative examples are separate.
The standard offers a common way to ask which interfaces a contract implements. The answer needs to be interpreted within that narrow purpose.
01 · VERIFIED RECORD
What the primary record establishes
ERC-165 has Final status and defines supportsInterface(bytes4). Its interface identifiers are formed from the XOR of function selectors. The detection procedure checks support for ERC-165 itself and requires the invalid identifier 0xffffffff to return false. ERC-165 — Standard Interface Detection, Final specification ↗
The specification places a 30,000-gas limit on the interface query and then describes querying another interface identifier. This procedure concerns discovery of an interface; it is not a review of every possible execution path in the contract. ERC-165 — Standard Interface Detection, Final specification ↗
02 · WFN EDITORIAL ANALYSIS
What the distinction changes
WFN’s interpretation is that a positive response can guide integration, but it cannot establish sound economics, safe permissions or the absence of implementation defects. Those are different assessments.
Conversely, failing this discovery procedure does not automatically prove that an address has no usable functions. The standard notes that older contracts may need their interfaces determined through other methods.
03 · REVIEW POINTS
What to check before drawing a conclusion
Retain the network, contract address, queried identifier and block reference in a compatibility test. A label in a product page is less specific than the response from the actual deployed contract.
Use interface detection to select an interaction path, then verify the behaviour relevant to that path. This article does not treat an interface claim as certification by Ethereum or as evidence that a transaction will succeed under every state and input.
