Reckon

Reckon is an email verification service that checks addresses in real time so teams can reduce bounces and protect sender reputation. It is designed to sit inside existing automation flows as a single send/receive data node, returning structured results that workflows can branch on, such as sending or suppressing a welcome campaign.

The service exposes an API with easy-to-parse JSON responses, request IDs for issue tracking, and LLM-friendly documentation. Checks include RFC format validation, plus-address detection, accept-all and role-based detection, domain checks, mailbox provider extraction, disposable detection, and SMTP checks. Security features include secret and client-side keys with rate limiting and domain whitelisting, along with a free sandbox for testing. Integrations cover the API, Zapier, a ChatGPT Plugin, an MCP Server for agents, and direct verification from Claude.

Reckon is aimed at operators and developers who rely on automation and want predictable verification costs. It is packaged as a free trial with no credit card required, after which users choose a plan. Plans are credit-based, with one credit equal to one verification and failed verifications free; each tier includes reporting and optional bonus usage with built-in spending caps.