Apply proposal

POST /api/v2/buyer/discovery/{discoveryId}/apply-proposal Applies a seller proposal returned by Discover products, auto-adding its products with the proposal’s recommended budget allocations. Requires discover-products to have run first so the proposal’s products are in the session cache. Defaults the distributed budget to proposal.totalBudgetGuidance.recommended; set replace: true to clear the existing selection before applying.

Request

curl -X POST https://api.interchange.io/api/v2/buyer/discovery/disc_01HZX3YQ7K9R6V3M2P1E0F8B2T/apply-proposal \
  -H "Authorization: Bearer $SCOPE3_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "proposalId": "proposal_acme_q3_sports",
    "totalBudget": 250000,
    "replace": true
  }'

Parameters

Field	Type	Required	Notes
`discoveryId`	string	Yes	Path param — session to apply into
`proposalId`	string	Yes	Proposal ID from the discover-products response
`totalBudget`	number	No	Budget to distribute across products. Defaults to `totalBudgetGuidance.recommended`
`replace`	boolean	No	When `true`, clears existing selected products before applying

Response

{
  "discoveryId": "disc_01HZX3YQ7K9R6V3M2P1E0F8B2T",
  "proposal": {
    "proposalId": "proposal_acme_q3_sports",
    "name": "Q3 Sports - premium CTV mix",
    "salesAgentName": "Acme Media Ad Sales"
  },
  "totalBudgetUsed": 250000,
  "productsApplied": 2,
  "productsSkipped": [],
  "products": [
    {
      "productId": "prod_acme_ctv_sports",
      "salesAgentId": "agent_acme_media",
      "bidPrice": 32.5,
      "budget": 150000,
      "groupId": "ctx_disc_01HZX3-group-0",
      "groupName": "Acme Media Connected TV",
      "selectedAt": "2026-06-07T15:04:00Z"
    }
  ],
  "totalProducts": 2,
  "budgetContext": { "sessionBudget": 250000, "allocatedBudget": 250000, "remainingBudget": 0 }
}

productsSkipped is non-empty when a proposal references a product that has aged out of the cached discovery results. Re-run discover to refresh the session, then re-apply.

Errors

400 VALIDATION_ERROR — missing proposalId, non-positive totalBudget, or discover-products was never run for this session.
404 NOT_FOUND — discoveryId or proposalId not found for the authenticated account.

See Errors for the full error contract.

Discovery overview

Proposals and refinement

Discover products

Surface proposals to apply

Get products

Inspect the resulting selection

Add products

Add products one at a time instead

Getting Started

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Request

Parameters

Response

Errors

Discovery overview

Discover products

Get products

Add products

​Request

​Parameters

​Response

​Errors

​Related

Discovery overview

Discover products

Get products

Add products

Request

Parameters

Response

Errors

Related