Agent onboarding via SKILL.md
Agents can sign up and onboard through a single skill file that points them through signup, OAuth, vocabulary, tools, safety gates, and a first-send path.
Nitrosend
Nitrosend is an AI email platform for agents and teams to automate marketing, transactional email, and inbox workflows via MCP, API, SDK, CLI, Claude, and Codex.
Email infrastructure for AI agents
Nitrosend is an email platform built for AI agents, with workflows that let agents sign up, onboard, send marketing and transactional email, and in some cases run their own inboxes. It is presented as a full-stack email layer for the agent economy, rather than a traditional email tool with AI added on top.
The product is accessed through MCP, API, SDK, CLI, and connected AI clients such as Claude and Codex. The source material emphasizes a headless workflow: agents read the skill file, connect to Nitrosend, create or manage email operations, and use human approval gates where appropriate.
Core features
Multiple access surfaces
Nitrosend exposes MCP, REST API, SDK, and CLI access on every plan, so agents and developers can use the same platform through chat clients, code, or terminal workflows.
Full-stack email automation
The platform supports marketing and transactional email, including flows, newsletters, campaigns, and branded transactional sends.
Agent inboxes and replies
The homepage says agents can create real inboxes on their own apex domain, receive inbound mail, and hold searchable conversations with customers; replies can be escalated to humans when needed.
Configurable AI and sending stack
The pricing page says paid plans can use frontier AI models, BYO sending keys, and BYO AI keys, while the Free plan uses smaller models.
Human oversight controls
The product includes approval gates and smart forwarding so agents can handle routine messages while routing edge cases to the right human inbox.
Common use cases
Agent-led setup and first send
Use Nitrosend when an agent should create an account, connect a domain, and send a first test or live campaign without a manual dashboard workflow.
Marketing and transactional email execution
Use it to run newsletters, campaigns, welcome flows, and transactional messages from an AI client such as Claude or a coding agent such as Codex.
Agent inbox handling
Use the beta inbox features when an agent needs its own address on your apex domain, with inbound replies, confirmations, and support threads routed into the same workflow.
Human-in-the-loop customer replies
Use the approval gates and smart forwarding when agents should handle routine responses but escalate sensitive or ambiguous messages to a human.
Multi-brand email operations
Use the shared platform and unlimited contacts model when multiple brands or clients need separate email operations under one account.
Pros and Cons
Pros
- Built for agent workflows, including self-onboarding, email sending, inbox handling, and reply triage.
- Multiple access paths are available, including MCP, API, SDK, and CLI, and these are not gated to only higher tiers.
- The pricing model keeps contacts unlimited and charges for sends rather than stored contacts.
- Agents can work with human approval gates, which supports mixed human-and-agent email operations.
- The platform supports both marketing and transactional email, plus newsletters, flows, and campaigns.
Cons
- Some agent inbox functionality is still in beta by request.
- The SKILL.md file notes that several agent capabilities, such as outbound outreach and goal-based marketing, are still coming soon or in development.
- Paid plan limits and add-ons still apply, so heavy usage may require higher tiers or extra-send charges.
FAQ
How do agents get started with Nitrosend?
Nitrosend supports signup and onboarding through its MCP workflow or through its REST API and CLI surfaces. The SKILL.md file says OAuth handles signup and auth in flow for standard clients, while headless coding-agent paths can create an account over HTTP and mint an API key before sending.
What kinds of email work is Nitrosend designed for?
The product is built for agents that need to send marketing and transactional email, manage inboxes, and respond to customers. The homepage also positions it as a layer for agent signup, onboarding, outbound email, and inbox handling, with human approval gates where needed.
Does Nitrosend work with AI tools and coding agents?
Yes. The pricing page says all plans include full access to Nitrosend MCP, API, and CLI. The homepage also gives connector examples for Claude Code and Codex, and the Claude-specific page shows a remote MCP setup for Claude Desktop and Claude Code.
Can agents receive and reply to email, or only send it?
The homepage says agents can have real inboxes on their own apex domain, with inbound replies, confirmations, and support threads landing on the contact that sent them. It also notes that inboxes are currently in beta by request.
Is there a free plan?
The pricing page says the Free plan includes unlimited contacts, 8,000 emails to start, then 500 emails per month after that, with no credit card required. Paid plans add higher volume, more brands, and additional options such as removable branding and BYO keys.
Quick Facts
- Category
- AI email platform
- Primary users
- AI agents, developers, and teams using agents to manage email
- Access surfaces
- MCP, API, SDK, CLI, and connected AI clients
- Supported email work
- Marketing email, transactional email, inbox replies, campaigns, and flows
- Pricing model
- Free plan available; paid plans charge by send volume, not contacts
- Source domain
- nitrosend.com
Nitrosend Alternatives
AgentMail
AgentMail is an email inbox API for AI agents to create, send, receive, and search messages via REST APIs and SDKs. Built for threaded workflows, verification, support, scheduling, and approvals.
ByteAsk
ByteAsk is a terminal-first AI coding agent for C and C++ that edits repos and verifies changes with compilers, debuggers, sanitizers, and tests.
Lasso
Lasso is an ecommerce product data platform for enriching catalog records, processing supplier files, generating product content, and tracking competitors. It includes a web app, REST API, SDK, and MCP server.
CreateOS Sandbox
CreateOS Sandbox is an isolated compute environment for running code and agent workloads in Firecracker micro-VMs with private networking and SDK, CLI, or MCP control.
Liam
Liam is an AI copilot for inbox management, email replies, prioritizing messages, and scheduling meetings. Free for individuals; custom pricing for teams and enterprise.
hob
hob is an independent workspace for coding agents, with local control over sessions, terminals, history, routing, and follow-up work.