# ISO date range list

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

Enumerate the dates in an inclusive [start, end] range stepped by a whole number of days.

**Use when you need to: iso date range list · enumerate dates between two dates · every nth day in range.**

## Supported

- iso date range list
- enumerate dates between two dates
- every nth day in range

## Not supported

- calendar-unit steps (weeks, months)
- timezones
- descending output

## Behavior

- start and end are strict YYYY-MM-DD calendar dates with year 0001-9999. start must not be after end.
- step_days is an optional JSON integer >= 1, default 1.
- dates lists start, start+step_days, start+2*step_days, ... up to and including end only when it lands exactly on a step; it never exceeds end. At most 10000 dates are returned, or the call is rejected.

## Input

- `start` (string, required): min length 10; max length 10; pattern `^\d{4}-\d{2}-\d{2}$`
- `end` (string, required): min length 10; max length 10; pattern `^\d{4}-\d{2}-\d{2}$`
- `step_days` (integer, optional): min 1

## Output

- `dates` (array of string, required): each min length 10; each max length 10

## Limits

- year min: 1
- year max: 9999
- max items: 10000

## Example

Request input:

```json
{
  "start": "2026-09-01",
  "end": "2026-09-05"
}
```

Response:

```json
{
  "result": {
    "dates": [
      "2026-09-01",
      "2026-09-02",
      "2026-09-03",
      "2026-09-04",
      "2026-09-05"
    ]
  }
}
```

## How to call it

### MCP

Connect `https://computefirst.net/mcp` ([setup](/docs#connect)), then call `execute` with:

```json
{
  "id": "iso-date-range-list",
  "version": "1.0.0",
  "input": {
    "start": "2026-09-01",
    "end": "2026-09-05"
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/iso-date-range-list/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"start":"2026-09-01","end":"2026-09-05"}'
```

The machine-readable contract is at [/v1/tools/iso-date-range-list/versions/1.0.0](/v1/tools/iso-date-range-list/versions/1.0.0).

### CLI

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

Get the client at [/clients/cli/](/clients/cli/).

## Related tools

- [ISO date weekday occurrences in range](/tools/iso-date-weekday-occurrences-in-range): List every date within an inclusive date range that falls on a given ISO weekday.
- [ISO date age](/tools/iso-date-age): Compute the calendar-aware elapsed years, months, and days between a birth date and an as-of date.
- [ISO date business days count](/tools/iso-date-business-days-count): Count the business days in an inclusive date range, skipping caller-supplied weekend weekdays and holidays.
- [ISO date range intersect](/tools/iso-date-range-intersect): Compute the intersection of two inclusive [start, end] date ranges.
- [ISO date compare](/tools/iso-date-compare): Compare two YYYY-MM-DD calendar dates and return -1, 0, or 1.
- [ISO date day of year](/tools/iso-date-day-of-year): Return the ordinal day number (1-366) of a YYYY-MM-DD date within its calendar year.