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SMS Validator API

Official registry Other

Validate SMS-capable phone numbers — mobile vs landline, E.164 format. x402 micropayment.

Source code Website Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

Remote (sse)
Claude Code 
claude mcp add --transport sse sms-validator-api 'https://sms-validator.api.klymax402.com/mcp'
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "sms-validator-api": {
            "type": "sse",
            "url": "https://sms-validator.api.klymax402.com/mcp"
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. SMS Validator API
  2. Quickstart -- MCP
  3. Quickstart -- HTTP (x402)
  4. Tools
  5. Example agent prompts
  6. Payment
  7. Part of klymax402
  8. License

SMS Validator API

Validate SMS-capable phone numbers -- mobile vs landline detection, carrier type, E.164 format, SMS readiness. Pay-per-call via x402 (USDC on Base L2) -- no API key, no signup, no rate-limit wall.

Part of the klymax402 marketplace -- 100 x402 micropayment APIs for AI agents, one wallet, USDC on Base.

Quickstart -- MCP

Add to your MCP client config (Claude Desktop, Cursor, ElizaOS, etc.):

{
  "mcpServers": {
    "sms-validator": {
      "url": "https://sms-validator.api.klymax402.com/mcp"
    }
  }
}

Quickstart -- HTTP (x402)

curl -X POST "https://sms-validator.api.klymax402.com/api/validate" \
  -H "Content-Type: application/json" \
  -d '{"phone":"..."}'
# -> 402 Payment Required, with an x402 payment challenge in the response body

Any x402-aware client (@x402/fetch, x402-agent-tools, ATXP) handles the 402 -> sign -> retry cycle automatically.

Tools

ToolMethodPathPriceDescription
sms_validate_numberPOST/api/validate$0.005Validate if a phone number can receive SMS
sms_validate_number

Use this when you need to check if a phone number can receive SMS messages. Returns SMS capability data in JSON.

Parameters

NameTypeRequiredDescription
phonestringyesPhone number with country code (e.g. +14155551234)
countryCodestringnoISO 3166-1 alpha-2 country code hint (e.g. US, FR, GB)

Example response:

{"phone":"+14155551234","canReceiveSMS":true,"carrierType":"mobile","e164":"+14155551234","countryCode":"US","numberType":"mobile","carrier":"T-Mobile"}

When to use: sending SMS campaigns, FOR filtering landlines from SMS lists, verifying 2FA phone numbers, and OTP delivery validation.

Not for: full phone validation with carrier lookup (use phone_validate_number), email validation (use email_verify_address), address validation (use address_validate).

Example agent prompts

  • "Check if a phone number can receive SMS messages"

Payment

  • Protocol: x402 -- HTTP-native pay-per-call, no signup, no API key
  • Network: Base L2 (eip155:8453)
  • Asset: USDC
  • Facilitator: Coinbase CDP (primary), PayAI (fallback)
  • Also reachable via ATXP (OAuth-wrapped x402, RFC 9728 protected-resource metadata)

Part of klymax402

100 x402 micropayment APIs for AI agents -- one wallet, USDC on Base, zero signup.

License

MIT

Frequently asked questions

What is SMS Validator API?

Validate SMS-capable phone numbers — mobile vs landline, E.164 format. x402 micropayment.

How do I install SMS Validator API?

It runs as a remote server. In Claude Code: claude mcp add --transport sse sms-validator-api 'https://sms-validator.api.klymax402.com/mcp'. For other clients, paste the JSON configuration from this page into their MCP settings.

Does SMS Validator API need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is SMS Validator API open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains SMS Validator API?

It is published by Br0ski777. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.