Submit updates

This guide covers submitting new values to issuer-signed scalar feeds, managing nonces, and monitoring feed staleness.

How issuer-signed updates work

The platform signs an EIP-712 typed data message on behalf of the authenticated user, containing the new value, observation timestamp, and nonce. The signed message is submitted on-chain, where the feed contract verifies the signature against the user's OnchainID identity and the trusted issuers registry before storing the new round.

Prerequisites

Before submitting feed updates, the authenticated user must:

1. Have a registered OnchainID identity -- the platform derives the issuer identity contract from the authenticated user automatically
2. Be a trusted issuer -- the user's identity must be added as a trusted issuer for the feed's claim topic via the trusted issuers registry

Get the current nonce

Before submitting an update, retrieve the current nonce for the issuer's identity contract on the target feed:

curl "$DALP_API_URL/system/feeds/0xFeed/nonce/0xIdentityContract" \
  -H "X-Api-Key: $API_KEY"

The issuerIdentity path parameter is the OnchainID identity contract address, not the EOA wallet address. Nonces are tracked per identity contract on-chain.

Response:

{
  "feedAddress": "0x...",
  "issuerIdentity": "0x...",
  "currentNonce": "5",
  "nextNonce": "6"
}

Use nextNonce when constructing your submission. The feed contract rejects updates with a nonce that does not match the expected next value.

Submit an update

curl -X POST "$DALP_API_URL/system/feeds/0xFeed/submit" \
  -H "X-Api-Key: $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "value": "150000000",
    "observedAt": 1700000000,
    "deadline": 0
  }'

The feed address is specified in the URL path. The issuer identity is derived automatically from the authenticated user's OnchainID identity contract.

Parameters

Response:

{
  "transactionHash": "0x...",
  "feedAddress": "0x...",
  "value": "150000000",
  "nonce": "6"
}

Submit flow

Read feed configuration

Query the immutable configuration of an issuer-signed feed to understand its parameters:

curl "$DALP_API_URL/system/feeds/0xFeed/config" \
  -H "X-Api-Key: $API_KEY"

Response:

{
  "feedAddress": "0x...",
  "subject": "0x...",
  "topicId": "0x...",
  "expectedSchemaHash": "0x...",
  "decimals": 8,
  "description": "USD price feed",
  "historyMode": "BOUNDED",
  "historySize": 100,
  "requirePositive": true,
  "driftAllowance": 300,
  "domainSeparator": "0x...",
  "trustedIssuersRegistry": "0x...",
  "topicSchemeRegistry": "0x..."
}

Key fields:

Check staleness

Determine whether a feed's latest value is fresh enough for a given use case:

curl "$DALP_API_URL/system/feeds/0xFeed/staleness?maxAgeSeconds=3600" \
  -H "X-Api-Key: $API_KEY"

Response:

{
  "feedAddress": "0x...",
  "latestUpdatedAt": "1700000000",
  "currentTimestamp": "1700003500",
  "ageSeconds": 3500,
  "maxAgeSeconds": 3600,
  "isStale": false,
  "roundId": "6",
  "answer": "150000000"
}

Use staleness checks before consuming feed data in critical operations (e.g., collateral valuation, settlement pricing) to ensure the value is sufficiently recent.