Why catchotp

Yes — catchotp covers the same primitive that most Mailosaur users actually reach for: programmable email inboxes with a real-time waiter for OTPs and verification links. The differences worth knowing: catchotp starts free (5 inboxes, 1,000 messages/mo, 24h retention) instead of per-seat pricing, ships a first-class MCP server for AI agents, and is opinionated about the inbox primitive rather than the dashboard. If you need render-preview across 80 mail clients or deliverability scoring, an enterprise platform like Mailosaur is still the right pick. If you need create / wait / parse / OTP at a fraction of the cost, catchotp is the fit.

Both expose programmable inboxes via REST API and SDKs; catchotp differentiates on the OTP primitive. catchotp parses one-time codes out of message bodies automatically and exposes a long-poll waitForOtp() that resolves the moment a code lands — typically under 700ms p50. Pricing model differs too: catchotp has a forever-free tier (no card required) and a $29/mo Pro tier; we don't charge per-inbox or per-API-call surcharges. Both products solve the "inbox-as-an-API" category — pick catchotp if OTP testing or AI agents are the wedge use case.

Yes — the Free tier is forever-free, no credit card required, and it includes 5 concurrent inboxes, 1,000 messages per month, 24-hour retention, and 2 concurrent waiters. It is enough to power the email tests of a small CI pipeline, a personal indie project, or to evaluate the API end-to-end before deciding whether to upgrade. You sign up at app.catchotp.com, get an API key inside a minute, and start creating inboxes immediately.

Mailinator and Temp-Mail are consumer-facing disposable inbox sites — they are great for a one-off signup but they have no API and their domains sit on every major signup blocklist. catchotp is an API-first developer tool: every action (create inbox, list messages, wait for OTP, parse links) is a single SDK call or HTTP request. The catchotp domain (inbox.catchotp.com) is a real domain with proper MX, DKIM, and abuse-handling, so it is not pre-blocked the way generic "temp mail" domains are.

For unit and component tests, Mailpit/MailHog are still excellent — they run locally in a sidecar and cost nothing. catchotp is the right pick when you need to test the production path: real DNS, real MX, real TLS handshake, real spam filters, real DKIM signing. Most teams use both: Mailpit for fast unit tests in the dev loop, catchotp for the real-email E2E tests that catch the bugs Mailpit cannot exercise (SPF/DKIM misconfig, transactional provider rate limits, deliverability regressions).

Yes. Pro and Team plans support webhooks per inbox or per workspace. You configure the URL plus a signing secret; on every received message or parsed OTP, catchotp POSTs a structured JSON payload with an HMAC signature you verify in your handler. This is useful for long-running agent loops (where the agent suspends until the webhook fires instead of holding a long-poll) and for integrating with TestRail, Xray, or Zephyr-style test management. Webhooks are not on the Free tier — long-polling covers most CI use cases.

Yes — agent use cases are a first-class part of the product. catchotp ships an MCP (Model Context Protocol) server (npx @catchotp/mcp) that exposes inbox creation, message reading, and the OTP waiter as agent-callable tools. Drop it into Claude Desktop, Cursor, Claude Code, or any MCP-aware host and the agent gains a real email inbox without any glue code. The waiter is long-poll, so the agent yields rather than burning tokens on a polling loop.

No, catchotp is a hosted SaaS. The architecture (SES inbound, EventBridge fan-out, DynamoDB streams, long-poll waiter Lambdas) is tightly coupled to AWS managed services and does not ship as an installable package. Enterprise customers needing data residency can pick the EU region once it ships (Q3 roadmap), or request a single-tenant deployment in their AWS account on a case-by-case basis. For air-gapped or fully on-prem requirements, Mailpit + a custom OTP parser is the closer fit.