Create feeds

This guide covers three ways to add feeds to the FeedsDirectory: deploying new issuer-signed feeds, creating aggregator adapters, and registering external feed contracts.

Create an issuer-signed scalar feed

Issuer-signed feeds are deployed via the IssuerSignedScalarFeedFactory addon. Updates are authorized through EIP-712 typed data signatures from trusted issuers.

Prerequisites

Verify the factory is installed:

curl "$DALP_API_URL/system/feeds/capabilities" \
  -H "X-Api-Key: $API_KEY"

Check that issuerSignedScalarFeedFactory.installed is true in the response.

Register a topic

Before creating a feed, register the topic name in the TopicSchemeRegistry. The API accepts either a human-readable topicName string, a topicId hash, or both. When topicName is provided, the on-chain topicId is computed internally. When both are provided, the API verifies they match.

Deploy the feed

curl -X POST "$DALP_API_URL/system/feeds/issuer-signed/create" \
  -H "X-Api-Key: $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "subject": "0xTokenAddress",
    "topicName": "PRICE/USD",
    "decimals": 8,
    "description": "USD price feed for token",
    "historyMode": "BOUNDED",
    "historySize": 100,
    "requirePositive": true,
    "driftAllowance": 0
  }'

You can also use topicId instead of topicName:

curl -X POST "$DALP_API_URL/system/feeds/issuer-signed/create" \
  -H "X-Api-Key: $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "subject": "0xTokenAddress",
    "topicId": "109530253152918849413157129862927938307097811649912148858507112538040816216783",
    "decimals": 8,
    "description": "USD price feed for token",
    "historyMode": "BOUNDED",
    "historySize": 100,
    "requirePositive": true,
    "driftAllowance": 0
  }'

Parameters

Response (synchronous, default):

{
  "data": {
    "feedAddress": "0x...",
    "subject": "0x...",
    "topicId": "0x...",
    "decimals": 8,
    "historyMode": "BOUNDED",
    "transactionHash": "0x..."
  },
  "meta": { "txHashes": ["0x..."] },
  "links": { "self": "/system/feeds/issuer-signed/create" }
}

To request asynchronous processing, add Prefer: respond-async to the request headers. The server returns HTTP 202 with a status URL for polling:

{
  "transactionId": "01965a1b-...",
  "status": "pending",
  "statusUrl": "/transactions/01965a1b-..."
}

Poll the statusUrl until status changes to "completed" or "failed".

The feed is automatically registered in the FeedsDirectory upon creation.

Permissions

Feed creation supports two authorization paths:

1. Feeds Manager role (system-level) — can create feeds for any subject including global (address(0)).
2. Governance role on subject token — holders of the GOVERNANCE role on a specific DALP token can create feeds for that token, provided the token supports the ISMART and ISMARTTokenAccessManaged interfaces. Does not apply to global feeds.

If neither condition is met, the factory reverts with UnauthorizedFeedCreation.

Create an aggregator adapter

Adapters are stable-address proxies that resolve to the current underlying feed for a (subject, topic) pair. Consumers point at the adapter address instead of the feed directly. When you replace the underlying feed, the adapter automatically resolves to the new feed without consumers changing their configuration.

Prerequisites

Verify the adapter factory is installed:

curl "$DALP_API_URL/system/feeds/capabilities" \
  -H "X-Api-Key: $API_KEY"

Check that scalarFeedAggregatorAdapterFactory.installed is true.

Deploy the adapter

curl -X POST "$DALP_API_URL/system/feeds/adapters/create" \
  -H "X-Api-Key: $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "subject": "0xTokenAddress",
    "topicName": "PRICE/USD"
  }'

Response (synchronous, default):

{
  "data": {
    "adapterAddress": "0x...",
    "subject": "0x...",
    "topicId": "0x...",
    "transactionHash": "0x..."
  },
  "meta": { "txHashes": ["0x..."] },
  "links": { "self": "/system/feeds/adapters/create" }
}

Add Prefer: respond-async for asynchronous processing (HTTP 202 with statusUrl for polling).

Permissions

Adapter creation follows the same two-path authorization as feed creation:

1. Feeds Manager role (system-level) — can create adapters for any subject including global (address(0)).
2. Governance role on subject token — can create adapters for their specific token. Does not apply to global subjects.

Register an external feed

Register an existing feed contract (e.g., a Chainlink price feed) in the directory so it can be discovered through the same (subject, topic) lookup as platform-managed feeds.

curl -X POST "$DALP_API_URL/system/feeds/register-external" \
  -H "X-Api-Key: $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "subject": "0xTokenAddress",
    "topicName": "PRICE/USD",
    "feedAddress": "0xExternalFeedContract",
    "kind": "SCALAR"
  }'

Directory operations

Resolve a feed

Look up the feed registered for a (subject, topic) pair. You can use either topicName or topicId:

curl "$DALP_API_URL/system/feeds/resolve?subject=0xToken&topicName=PRICE/USD" \
  -H "X-Api-Key: $API_KEY"

Or with topicId:

curl "$DALP_API_URL/system/feeds/resolve?subject=0xToken&topicId=109530253..." \
  -H "X-Api-Key: $API_KEY"

Returns the feed address, kind, schema hash, adapter address (if one exists), and indexed data from DIDX.

Replace a feed

Swap the feed registered for a (subject, topic) pair with a different feed contract:

curl -X PUT "$DALP_API_URL/system/feeds/replace" \
  -H "X-Api-Key: $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "subject": "0xTokenAddress",
    "topicName": "PRICE/USD",
    "newFeedAddress": "0xNewFeedContract",
    "kind": "SCALAR"
  }'

If an aggregator adapter exists for this (subject, topic), it automatically resolves to the new feed.

Remove a feed

Remove a feed registration from the directory:

curl -X DELETE "$DALP_API_URL/system/feeds/remove" \
  -H "X-Api-Key: $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "subject": "0xTokenAddress",
    "topicName": "PRICE/USD"
  }'