Milestone slack & risk API

Computes slack for each milestone as working days available between now and the due date minus remaining work days, flagging at-risk milestones with negative slack. Answers 'Which milestones are at risk of slipping?', 'How much buffer does each milestone have?'.

Price$0.02per request

MethodPOST

Route/v1/scheduling/milestone-slack

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

schedulingprojectmilestoneslackriskdeadlineworking-daysagents

API URLhttps://x402.hexl.dev/v1/scheduling/milestone-slack

Integration docs

Example request

{
  "now": "2026-06-04",
  "milestones": [
    {
      "id": "m1",
      "due": "2026-06-12",
      "remainingWorkDays": 4
    },
    {
      "id": "m2",
      "due": "2026-06-10",
      "remainingWorkDays": 6
    }
  ]
}

Example response

{
  "now": "2026-06-04",
  "milestones": [
    {
      "id": "m2",
      "due": "2026-06-10",
      "availableWorkDays": 4,
      "remainingWorkDays": 6,
      "slackDays": -2,
      "status": "at-risk"
    },
    {
      "id": "m1",
      "due": "2026-06-12",
      "availableWorkDays": 6,
      "remainingWorkDays": 4,
      "slackDays": 2,
      "status": "on-track"
    }
  ],
  "worstSlackDays": -2,
  "atRiskCount": 1,
  "interpretation": "1 milestone(s) at risk; worst is 'm2' (-2d)."
}

Input schema

{
  "type": "object",
  "required": [
    "now",
    "milestones"
  ],
  "properties": {
    "now": {
      "type": "string",
      "examples": [
        "2026-06-04"
      ]
    },
    "milestones": {
      "type": "array",
      "items": {
        "type": "object"
      }
    },
    "workweek": {
      "type": "array",
      "items": {
        "type": "number"
      }
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}