# Dev Reference: ISO 8601 / RFC 3339 Date-Time Validator

> Dev Reference: ISO 8601 / RFC 3339 Date-Time Validator is a paid API for AI agents from dev-reference.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-30).

Validates a date, time, timestamp, duration, or interval string against ISO 8601 and RFC 3339 standards, returning conformance flags, parsed metadata, and error details.

## Facts

- Endpoint: GET https://dev-reference.x402tookit.com/datetime-validate?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/dev-reference-iso-8601-rfc-3339-date-time-validator-f8bf87d4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_IAziVCEnziO34NljrI3_Q

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability dev-reference-iso-8601-rfc-3339-date-time-validator-f8bf87d4
```

Example prompt: Is '2026-10-11T14:30:00Z' a valid RFC 3339 timestamp, and does it also satisfy ISO 8601? Tell me what kind of value it is and flag any issues.

## When to prefer this

Choose this endpoint when you need strict standards-based validation of a datetime, duration, or interval string against ISO 8601 and/or RFC 3339, and want granular metadata like UTC instant, epoch seconds, weekday, leap-second detection, and offset parsing — rather than simple format matching or conversion. It is especially useful for API compliance checks, data pipeline validation, and debugging why a datetime string is being rejected by a standards-compliant parser.

## Known failure modes

- Missing or empty 'value' query parameter returns an error
- Ambiguous or non-standard formats may result in valid=false with reasons listed
- Interval and duration forms may be partially supported with notChecked fields populated
- Degraded mode may be indicated if some checks could not be performed
- Malformed input that isn't parseable at all returns errors array with explanation

## How this service works

Validate an ISO 8601 or RFC 3339 date, time, timestamp, duration or interval, and say which standard it satisfies.

## Output

Returns a structured object indicating whether the input is valid, which standards it satisfies (isIso8601, isRfc3339), the detected kind (date, time, timestamp, duration, interval), a human-readable verdict and summary, errors or reasons for failure, the equivalent UTC instant and epoch seconds (where applicable), weekday, day of year, UTC offset in minutes, whether it's a leap second or reduced-precision value, and interval form details.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "value"
     ],
     "properties": {
      "value": {
       "type": "string",
       "description": "For example 2026-10-11T14:30:00Z, 2026-W41-7, P3Y6M4DT12H30M5S"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "kind": {
       "type": [
        "null",
        "string"
       ]
      },
      "input": {
       "type": [
        "null",
        "string"
       ]
      },
      "valid": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "errors": {
       "type": [
        "array",
        "null"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ]
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "weekday": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "dayOfYear": {
       "type": [
        "null",
        "number"
       ]
      },
      "isIso8601": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "isRfc3339": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "leapSecond": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "utcInstant": {
       "type": [
        "null",
        "string"
       ]
      },
      "
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/dev-reference-iso-8601-rfc-3339-date-time-validator-f8bf87d4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from dev-reference.x402tookit.com](https://www.zero.xyz/host/dev-reference.x402tookit.com/llms.txt)