e2a review
A flexible email API for agent workflows, inbound mail, and threaded conversations.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
e2a is an email API for developers and businesses building transactional email or agent-owned inboxes. It combines outbound sending over HTTP with inbound mail, threaded replies, persistent conversations, signed delivery webhooks, WebSockets, templates, and optional human approval workflows. Teams can access it through REST, TypeScript, or Python, connect through MCP, use SMTP relay, or run the Apache-2.0 stack themselves. Its positioning fits applications where email is part of an automated or agent-aware workflow rather than only a one-way notification channel.
The plan structure scales by agents, domains, sends, and storage. Free includes 3 agents, 3 custom domains, 3,000 monthly sends, 1 GiB of storage, SPF/DKIM verification, and real-time WebSocket delivery. Starter costs $10 per month for 10 agents, 5 domains, 20,000 sends, 5 GiB, and HITL approval workflows. Pro costs $20 per month and raises those limits to 25 agents, 10 domains, 50,000 sends, and 10 GiB. Scale costs $99 per month for 250 agents, 150 domains, 200,000 sends, 100 GiB, everything in Pro, and priority support.
The standout capability is the combination of inbound email and conversation handling with agent controls. Threaded replies, persistent conversations, signed webhooks, WebSocket delivery, and MCP connectivity give developers several ways to connect email events to application logic. The optional human-in-the-loop approval workflow is particularly relevant when automated agents need review before sending. Choose e2a when you need programmable inbound and outbound email, agent-owned inboxes, or self-hosting. Consider another email API if your primary requirement is a narrower sending service rather than conversational and agent-aware workflows.
e2a pros and cons
- Where it wins
- Inbound mail, agent-owned inboxes, and threaded replies
- REST API, SDKs, MCP, webhooks, WebSockets, and SMTP relay
- Hosted plans plus an Apache-2.0 self-hosted stack
- Where it doesn't
- Free plan is limited to 3 agents, 3 domains, and 3,000 sends
- Human approval workflows begin with the Starter plan
- Higher usage requires moving to paid monthly tiers
e2a fact sheet, pricing and score →
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