Fund Milestone

Requests escrow funding for a NOT_FUNDED milestone. This call never moves money. It records a pending approval (type: "milestone_fund") and returns 202; a signed-in human must open approval.approvalUrl and confirm in the OpenTrain app before the milestone is funded. Approvals expire after ~72 hours.

Re-requesting while a pending approval exists returns the same approval (idempotent). Learn the outcome by polling GET /approvals/{id} or watching for the approval.confirmed event on GET /updates. The request has no body. Funding is drawn per the account’s billing setup — see credits & billing.

Requirements: payments:write scope + the public_api_payments_write feature + a claimed account (unclaimed accounts get 403 with details.reason: "account_claim_required" and a claimUrl) + a payment method on file (409 with details.reason: "payment_method_required" otherwise).

Request

milestoneIdstringpathrequired

The milestone to fund. Must be NOT_FUNDED, not cancelled, on an active contract you own.

Response

Returns 202 — the request is recorded, nothing has been charged yet.

approvalobject

The pending approval, in the same shape as GET /approvals/{id}: {id, type: "milestone_fund", status: "pending", contractId, milestoneId, jobId, proposalId: null, approvalUrl, expiresAt, resolvedAt, result, createdAt}.

messagestring

Explains that a signed-in human must confirm the approval before any money moves.

Errors

Status	code	Meaning
401	UNAUTHORIZED	Missing or invalid token
403	FORBIDDEN	Missing payments:write scope, public_api_payments_write disabled, or account not claimed (details.reason: "account_claim_required", details.claimUrl)
404	NOT_FOUND	No such milestone, or its contract is on another account
409	CONFLICT	See the reason catalog below

409 reason catalog

details.reason	Meaning	Extra details fields
milestone_not_fundable	Milestone is not NOT_FUNDED (e.g. already funded)	status
payment_method_required	No payment method on file; a human must add a card in the OpenTrain app	billingUrl
milestone_cancelled	Milestone has been cancelled	—
contract_ended	The contract has ended	contractId

Request examples

curlCLIMCP: opentrain_request_milestone_funding

curl

curl -sS -X POST https://app.opentrain.ai/api/public/v1/milestones/<MILESTONE_ID>/fund \
  -H "Authorization: Bearer $OT_API_TOKEN"

CLI

opentrain milestones fund --milestone-id <MILESTONE_ID> --json

MCP: opentrain_request_milestone_funding

{
  "milestoneId": "<MILESTONE_ID>"
}

Response examples

202409 (payment method required)

202

{
  "approval": {
    "id": "<APPROVAL_ID>",
    "type": "milestone_fund",
    "status": "pending",
    "contractId": "<CONTRACT_ID>",
    "milestoneId": "<MILESTONE_ID>",
    "jobId": "<JOB_ID>",
    "approvalUrl": "https://app.opentrain.ai/approvals/<APPROVAL_ID>",
    "expiresAt": "2026-06-15T10:00:00.000Z",
    "resolvedAt": null,
    "result": null,
    "createdAt": "2026-06-12T10:00:00.000Z"
  },
  "message": "Funding request recorded. A signed-in human must confirm this approval in the OpenTrain app before any money moves."
}

409 (payment method required)

{
  "error": "No payment method on file. A human must add a card in the OpenTrain app before milestone funding can be requested.",
  "code": "CONFLICT",
  "requestId": "<REQUEST_ID>",
  "details": {
    "milestoneId": "<MILESTONE_ID>",
    "reason": "payment_method_required",
    "billingUrl": "https://app.opentrain.ai/employer-settings?tab=billing"
  }
}