Trust Anchors API

The Trust Anchors API returns the OMA3-maintained trust anchors used by clients, widgets, and services to make local validation decisions. It provides EAS contract addresses, schema name-to-UID mappings, approved issuer lists, and widget origin allowlists.

Endpoint

GET https://api.omatrust.org/v1/trust-anchors

Response

{
  "version": 1,
  "updatedAt": "2026-05-02T00:00:00Z",
  "widgetOrigins": [],
  "chains": {
    "eip155:66238": {
      "name": "OMAChain Testnet",
      "easContract": "0x8835AF90f1537777F52E482C8630cE4e947eCa32",
      "schemas": {
        "user-review": "0x7ab3...",
        "linked-identifier": "0x26e2...",
        "key-binding": "0x807b...",
        "controller-witness": "0xc814..."
      }
    }
  },
  "registries": [
    {
      "type": "approved-issuers",
      "issuers": [
        {
          "address": "0x6f05D46...",
          "label": "OMA3 Testnet Attestation",
          "schemas": ["security-assessment", "certification"]
        }
      ]
    }
  ]
}

Fields

Field	Type	Description
version	number	Trust anchors response version. Increment on breaking response-shape changes.
updatedAt	string	ISO 8601 timestamp of the last trust anchor update.
widgetOrigins	string[]	Additional trusted widget origins beyond *.omatrust.org.
chains	object	CAIP-2 chain identifier (e.g., "eip155:66238") to chain-specific trust anchors.
chains.*.name	string	Human-readable chain name.
chains.*.easContract	string	Trusted EAS contract address on this chain.
chains.*.schemas	object	Schema name → schema UID mapping. Keys are human-readable schema names (e.g., "user-review", "certification"). Values are the deployed schema UIDs on this chain.
registries	object[]	OMA3-maintained trust registries.
registries[].type	string	Registry type. Currently only "approved-issuers".
registries[].issuers	object[]	List of approved issuers (when type is "approved-issuers").
registries[].issuers[].address	string	Wallet address or DID of the approved issuer.
registries[].issuers[].label	string	Human-readable label for the issuer.
registries[].issuers[].schemas	string[]	Schema names this issuer is approved for (e.g., ["certification"]).

Verifier Workflow

A verifier client can use trust anchors to validate attestations:

1. Fetch trust anchors: GET /v1/trust-anchors
2. Look up the schema UID by name: chains["eip155:66238"].schemas["certification"]
3. Query EAS for attestations with that schema UID
4. Filter results: check if the attester address appears in registries[0].issuers with the matching schema name in their schemas array

Method and CORS

GET only. OPTIONS returns 204 with CORS headers. Other methods return 405.

All responses include Access-Control-Allow-Origin: *.

SDK Helpers

The @oma3/omatrust SDK provides helper functions for working with trust anchors:

import { fetchTrustAnchors, getChainAnchors, getSchemaAnchor, extractAllowlists } from "@oma3/omatrust/widgets";

// Fetch and cache trust anchors (5-minute TTL)
const anchors = await fetchTrustAnchors();

// Look up chain-specific anchors by CAIP-2 identifier (throws UNSUPPORTED_CHAIN)
const chain = getChainAnchors(anchors, "eip155:66238");

// Look up a schema UID by name (throws INVALID_INPUT if not found on chain)
const schemaUid = getSchemaAnchor(anchors, "eip155:66238", "controller-witness");

// Extract all allowed contracts and schema UIDs across chains
const { allowedContracts, allowedSchemas } = extractAllowlists(anchors);