# agentshelf.syntexa.ch JSON Schema 2020-12 Validator

> agentshelf.syntexa.ch JSON Schema 2020-12 Validator is a paid API for AI agents from agentshelf.syntexa.ch, paid per call via x402, $0.009/call, status unknown (last checked 2026-09-29).

Validates a JSON value against a JSON Schema 2020-12 schema, handling dialect-specific edge cases like exclusive bounds and format keywords.

## Facts

- Endpoint: POST https://agentshelf.syntexa.ch/v1/check-schema-2020-12?utm_source=zero.xyz
- Price: $0.009/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentshelf-syntexa-ch-json-schema-2020-12-validator-d1d3cbe0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_RsoZaNEaP551PVteohv4z

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 agentshelf-syntexa-ch-json-schema-2020-12-validator-d1d3cbe0 -d '<json body>'
```

Example prompt: Can you check whether this JSON value is valid against my JSON Schema 2020-12 schema? The schema uses exclusiveMaximum and format keywords, and I need to make sure the data conforms correctly.

## When to prefer this

Choose this endpoint when you specifically need JSON Schema 2020-12 dialect validation, particularly when your schema relies on exclusive bounds (exclusiveMinimum/exclusiveMaximum) or format keyword behavior that differs between drafts. Use it when the free sandbox endpoint (/v1/sandbox/check-schema-2020-12) is unavailable or rate-limited. Prefer this over generic validators when dialect correctness is critical.

## Known failure modes

- Invalid or malformed JSON schema provided — returns schema parse error
- JSON value exceeds 20,000 character limit — returns payload too large error
- Unsupported schema dialect keyword causes parsing failure
- Payment of $0.009 USDC not provided — returns 402 Payment Required
- Network timeout or service unavailability

## How this service works

Call when an agent needs a limited JSON Schema 2020-12 check. Dialects disagree on exclusive bounds and format. Exact $0.009 USDC. Prefer unpaid POST /v1/sandbox/check-schema-2020-12 first.

## Output

Returns a validation outcome indicating whether the JSON value conforms to the provided JSON Schema 2020-12 schema, including any specific errors such as exclusive bound violations or format keyword mismatches.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "data": {
   "examples": [
    {
     "a": 1
    }
   ],
   "description": "JSON value for schema-check SKUs. Omit it on string checks such as email or IBAN."
  },
  "value": {
   "type": "string",
   "examples": [
    "{\"a\":1}"
   ],
   "maxLength": 20000,
   "minLength": 1,
   "description": "Value to check. The route description names the format: email, phone, IBAN, postal code, VAT, national id, or similar."
  },
  "schema": {
   "examples": [
    {
     "type": "object",
     "required": [
      "a"
     ],
     "properties": {
      "a": {
       "type": "integer"
      }
     }
    }
   ],
   "description": "JSON Schema document for schema-check SKUs. Omit it on string checks."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentshelf-syntexa-ch-json-schema-2020-12-validator-d1d3cbe0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentshelf.syntexa.ch](https://www.zero.xyz/host/agentshelf.syntexa.ch/llms.txt)