OpenSea Seaport: tax classification of its transactions
How OpenSea Seaport transactions classify for US tax: 112 verified contract-level rules across 5 chains, covering swap, fee payment, each resolving to a category, a treatment, and a confidence score.
Example last verified 2026-08-06 against the live engine. CryptoTaxEdge Team.
What OpenSea Seaport does on-chain
Seaport is the settlement protocol behind OpenSea NFT trades. A sale is a disposition of the NFT for the seller and establishes basis for the buyer; offer acceptance, bundle sales, and private listings all settle through the same contract with different selectors.
Categories and house treatments
Verified OpenSea Seaport rules map to these categories from the closed classification taxonomy. Categories flagged as grey areas expose a documented house default and the alternative position, configurable per firm.
| Category | House treatment | Rules |
|---|---|---|
swap | disposal | 70 |
fee_payment | expense | 42 |
A real classification
{
"api_version": "v1",
"hash": "0x2e7b5cc95397886b3a54f8ce32a0dce1d0789ad72c0f26c9b4c444c1289cc566",
"chain": "ethereum",
"category": "swap",
"treatment": "disposal",
"taxable": true,
"confidence": 95,
"needs_review": false,
"ledger_action": "Trade",
"protocol": "OpenSea Seaport",
"description": "Token swap via OpenSea Seaport; a taxable disposition under IRC §1001.",
"review_note": null,
"grey_area": null,
"assets": {
"sent": [
{
"symbol": "ETH",
"amount": "0.000256",
"decimals": 18,
"action": "transferred",
"native": true
}
],
"received": [
{
"symbol": "NFT",
"amount": "1",
"decimals": 0,
"token_id": "1673",
"token_type": "erc721",
"action": "received",
"token_address": "0x130e71d1ff47a5694574880d1b8ba41e300e262e",
"from": "0xb2c556ae326c39c117c54a2724327837a1625da7"
},
{
"symbol": "NFT",
"amount": "1",
"decimals": 0,
"token_id": "1674",
"token_type": "erc721",
"action": "received",
"token_address": "0x130e71d1ff47a5694574880d1b8ba41e300e262e",
"from": "0xb2c556ae326c39c117c54a2724327837a1625da7"
},
{
"symbol": "NFT",
"amount": "1",
"decimals": 0,
"token_id": "1675",
"token_type": "erc721",
"action": "received",
"token_address": "0x130e71d1ff47a5694574880d1b8ba41e300e262e",
"from": "0xb2c556ae326c39c117c54a2724327837a1625da7"
},
{
"symbol": "NFT",
"amount": "1",
"decimals": 0,
"token_id": "1676",
"token_type": "erc721",
"action": "received",
"token_address": "0x130e71d1ff47a5694574880d1b8ba41e300e262e",
"from": "0xb2c556ae326c39c117c54a2724327837a1625da7"
}
],
"gas": null
}
}
Verbatim wire response from the live engine. Last verified 2026-08-06 by live replay. Check any transaction yourself in the Classification Explorer.
Verified rules
Behind this page sit 112 verified rules for OpenSea Seaport. Each one binds a specific contract interaction on a specific chain to a category and treatment, with a confidence band earned from repeated on-chain observation and cross-source agreement. Rule coverage by chain: arbitrum (16), base (16), ethereum (48), optimism (16), polygon (16). A small illustrative sample:
| Chain | Category | Confidence |
|---|---|---|
| ethereum | fee_payment | high |
| base | fee_payment | high |
| arbitrum | fee_payment | high |
| optimism | fee_payment | high |
| polygon | fee_payment | high |
Illustrative sample of the 112 verified rules behind this page: the full mappings are served through the API.
Limitations
What this page does not decide. Coverage reflects the verified OpenSea Seaport contract set on the chains shown; deployments or peripheral contracts outside that set route to review rather than being guessed. Confidence is a corroboration signal, not an accuracy percentage, and grey-area categories are positions to be set at the firm level, not settled law. Chains: arbitrum, base, ethereum, optimism, polygon.
Frequently asked questions
What tax treatment does this page document?
House treatment follows the CryptoTaxEdge Classification Standard. Categories with no fixed mapping (GAP-3) tell you to read the treatment field on the record rather than infer it from the category name.
Where is the closed vocabulary published?
The versioned Classification Standard at https://cryptotaxedge.com/standard/ enumerates emitted categories and the five-treatment enum. This encyclopedia page is a worked example on top of that Standard.
Are the wire examples still current?
Yes. Each example is verbatim engine output, re-verified on a daily replay against the live engine.
Not tax advice. CryptoTaxEdge is software, not a licensed tax advisor. Classifications and the treatments described here are informational only; verify results and consult a qualified tax professional before filing. IRC section references are general framing. OpenSea Seaport is a third-party protocol; CryptoTaxEdge is not affiliated with it.