# Plumbline

> Email and phone validation API for AI agents and apps. REST API and a remote MCP server (Streamable HTTP). 50 free checks per day without a key; prepaid credits after that ($1 per 1,000).

Use Plumbline before sending email to an unverified address or storing a phone number. Each response has a `verdict` (valid | risky | invalid), a 0-100 `score` (email) and plain-English `reasons`.

## Endpoints
- GET https://plumbline-verify.pages.dev/v1/email?email=ADDRESS : format, domain exists, MX / null MX, disposable, role address, free provider, typo suggestion. No mailbox probing.
- GET https://plumbline-verify.pages.dev/v1/phone?phone=NUMBER&country=US : validity, country, line type (mobile, landline, toll_free, voip...), E.164 and national formats. No line-activity check.
- POST https://plumbline-verify.pages.dev/v1/batch : JSON {"emails": [...], "phones": [...]} up to 100 items.
- GET https://plumbline-verify.pages.dev/v1/account : credits left for a key.
- Auth: `Authorization: Bearer pl_...`, `X-API-Key: pl_...`, or `?key=pl_...`. Omit for the free allowance.
- Errors: 400 bad input, 401 unknown key, 402 out of credits / free allowance used (includes buy_url).

## MCP
- Server URL: https://plumbline-verify.pages.dev/mcp (append ?key=pl_... to use credits)
- Tools: validate_email, validate_phone, account_status

## Docs
- [OpenAPI spec](https://plumbline-verify.pages.dev/openapi.json)
- [Pricing and keys](https://plumbline-verify.pages.dev/#pricing)