Nuvrail

Nuvrail is an approval gateway proxy intercepts AI agent email writes and stages them for human review.

Nuvrail is an approval layer that sits between AI agents and mail servers. It acts as an IMAP and SMTP proxy that stages every write, delete, flag change, and outbound send for human approval. Reads pass through instantly while destructive actions require one tap to execute or reject. It features an IMAP proxy, SMTP proxy, staging engine, FastAPI REST API, and a React web Progressive Web App. It supports integrations with Claude Desktop, Cursor, LangChain, Google, and Microsoft.

Nuvrail at a glance

Best for: Software engineer
Runs on: Web, API, self-hosted, open source
Pricing: Free and open source
Released: October 2026
Category: AI productivity tool
Website: github.com/agens-field/nuvrail

Key features

Intercepts IMAP and SMTP writes for human review
Stages email deletes, moves, and outbound sends
Blocks permanent expunges at the gateway layer
Delivers push notifications for pending operations
Maintains an immutable audit log of all actions
Encrypts credentials at rest with AES-256-GCM

Use it for

Reviewing AI agent email sends before delivery
Approving or rejecting AI agent mailbox deletions
Monitoring AI agent IMAP and SMTP activities

Alternatives to Nuvrail

AgentMail — Enables AI agents to send and receive emails programmatically via REST API.
Nonce — It stops AI apps from collecting your entire inbox or searching unrelated files.
Clotr — Runs locally with no network or accounts required.
Resend Inboxes — Build workflows, share inboxes, and connect AI agents directly to email.
bytemail — Connects directly to email providers without using intermediary servers.
Google Workspace CLI — Dynamically builds commands from Google's Discovery Service with JSON output.
Clutterstrike — Provides immediate validation of suspicious digital communications.
Velozity — Combines team communication, shared virtual spaces, and built-in AI agents in one app.
Klar — Runs fully on the Mac without sending messages to the cloud.
Looper — AI teammates that own individual business metrics and run on a schedule.
Umbra Mail — It keeps mail private with no tracking and optional local AI.
Noodle Seed — Deploy custom AI agents across websites, apps, ChatGPT, Claude, and WhatsApp.

All Nuvrail alternatives