ISO date range union

iso-date-range-union · version 1.0.0 · Dates & times (UTC, ISO 8601) · free, no key needed

Merge overlapping or day-adjacent inclusive [start, end] date ranges into the fewest equivalent ranges.

Use when you need to: iso date range union · merge date ranges · combine overlapping date periods.

Supported

• iso date range union
• merge date ranges
• combine overlapping date periods

Not supported

• open ranges
• timezones
• datetime ranges

Behavior

• ranges is an array of 1-1000 inclusive [start, end] YYYY-MM-DD date ranges with year 0001-9999; start must not be after end in any entry.
• Two ranges merge when they overlap or are day-adjacent (one starts the calendar day immediately after the other ends).
• union is the sorted, non-overlapping, non-adjacent set of merged ranges covering exactly the same days as the input, ascending by start.

Input

• ranges (array of object, required): min items 1; max items 1000

Output

• union (array of object, required)

Limits

• year min: 1
• year max: 9999
• max ranges: 1000

Example

Request input:

{
  "ranges": [
    {
      "start": "2026-01-01",
      "end": "2026-01-05"
    },
    {
      "start": "2026-01-06",
      "end": "2026-01-10"
    },
    {
      "start": "2026-02-01",
      "end": "2026-02-05"
    }
  ]
}

Response:

{
  "result": {
    "union": [
      {
        "start": "2026-01-01",
        "end": "2026-01-10"
      },
      {
        "start": "2026-02-01",
        "end": "2026-02-05"
      }
    ]
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "iso-date-range-union",
  "version": "1.0.0",
  "input": {
    "ranges": [
      {
        "start": "2026-01-01",
        "end": "2026-01-05"
      },
      {
        "start": "2026-01-06",
        "end": "2026-01-10"
      },
      {
        "start": "2026-02-01",
        "end": "2026-02-05"
      }
    ]
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/iso-date-range-union/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"ranges":[{"start":"2026-01-01","end":"2026-01-05"},{"start":"2026-01-06","end":"2026-01-10"},{"start":"2026-02-01","end":"2026-02-05"}]}'

The machine-readable contract is at /v1/tools/iso-date-range-union/versions/1.0.0.

CLI

node cli.mjs run iso-date-range-union 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• ISO date range intersect: Compute the intersection of two inclusive [start, end] date ranges.
• ISO date range overlap: Test whether two inclusive [start, end] date ranges share at least one day.
• ISO date range split by month: Split an inclusive [start, end] date range into per-calendar-month sub-ranges.
• ISO date clamp: Clamp a YYYY-MM-DD calendar date into an inclusive [min, max] range.
• ISO date range contains: Test whether an inclusive [start, end] date range contains a given date.
• ISO date range list: Enumerate the dates in an inclusive [start, end] range stepped by a whole number of days.