The AI Email Assistant for Outlook That Actually Replies

Your Outlook inbox doesn't need another drafting tool

If you run a small business on Outlook, you already know the shape of the problem. The same questions arrive every day (pricing, availability, bookings, billing, "where's my order?") and every one of them waits for a human to open it, think about it, type an answer and press send. AI was supposed to fix this. Instead, most "AI email assistants" for Outlook (Copilot included) are drafting tools: they help you write faster, but you still touch every single message.

That gap matters more for a small business than for anyone else. A corporate employee with a slow inbox annoys colleagues; a small business with a slow inbox loses customers. The person asking about availability at 9pm books with whoever answers first. The "quick question" about pricing that sits unanswered for two days quietly becomes someone else's sale. Drafting tools don't change that maths, because the bottleneck was never the typing: it was the fact that a human had to be present at all.

InReply takes the other approach. It connects to your existing Outlook or Microsoft 365 mailbox via secure Microsoft OAuth, classifies each inbound email, writes a reply grounded only in the knowledge you've uploaded, and either sends it automatically or saves it as a draft for your review. The human handles the exceptions; the routine answers handle themselves.

And you don't need a Copilot license to get there. If you hit Microsoft's paywall, discovered Copilot can't be bought for Outlook alone, and went looking for something that does more than draft: that's exactly the gap this product sits in. InReply connects independently of your Microsoft plan, via the same OAuth flow you'd use for any trusted app.

If you arrived here comparing Copilot with the alternatives, stay: this page covers exactly that. We look at what Copilot does well, where it stops, and how the other Outlook AI tools compare, with every competitor fact dated so you can check it yourself.

Copilot drafts. An email agent replies. Here's the difference

Microsoft Copilot deserves an honest appraisal, because for what it is, it's good. It's native to Outlook: nothing to connect, nothing third-party. It has deep Microsoft 365 context: your calendar, your documents, your meeting history. If you spend your day writing one-off emails to colleagues and clients, Copilot genuinely speeds up the writing.

But look at the workflow. You open the email. You prompt Copilot. You review the draft. You edit it. You press send. That's AI-assisted, human-operated email: the time saved per message is real, but bounded, because you still handle every message personally. MaestroLabs' in-depth Copilot review (retrieved 22 July 2026) also notes practical limits: Copilot cannot be bought for Outlook alone, struggles with long or complex threads, and offers limited tone and personalisation controls.

An email agent inverts the model. An email arrives. It gets classified: support question, sales enquiry, needs-action. An answer is generated from your knowledge base. It's sent automatically (Autopilot) or saved as a draft for review (Ghost Mode). You only touch the exceptions: the messages that need a decision, not a reply.

Do the arithmetic on your own inbox and the difference becomes concrete. Say sixty customer emails arrive a day and a drafting assistant cuts each from four minutes to two. You still spend two hours a day on email: the assistant halved the typing, not the attendance. An agent that handles the forty routine ones outright leaves you twenty emails that genuinely need you. That's the difference between a tool that assists and a tool that operates.

To be equally clear about when Copilot is the right answer: if your inbox is mostly internal (colleagues, projects, meeting threads) and your organisation already pays for Microsoft 365 Copilot, use it. It's the natural choice for personal productivity inside Microsoft's ecosystem, and no third-party agent will match its access to your calendar and documents. The case for an agent begins where the email stops being about you and starts being about your customers.

On price, be careful with what you read: sources conflict. Lindy's July 2026 roundup lists Copilot "from $9.99/mo", while MaestroLabs' review puts Copilot Pro at $20/user/month and Copilot for Microsoft 365 at $30/user/month (both retrieved 22 July 2026). The $9.99 figure most likely reflects a Microsoft 365 Personal bundle rather than standalone Copilot. Verify the current tiers on Microsoft's own pricing page before you budget.

How InReply works with your existing Outlook inbox

There is nothing to migrate and nothing to switch. You connect the Outlook or Microsoft 365 mailbox you already use via Microsoft OAuth: no forwarding rules, no new client, no helpdesk. InReply uses Microsoft Graph (Mail.ReadWrite and Mail.Send) and operates on the mailbox itself, not as a client add-in, which means it works the same whether your team reads email in Outlook on the web, the desktop app or mobile. Replies go out from the same address your customers already write to, and you can disconnect or revoke access at any time.

That last point is worth pausing on, because it's where InReply differs from every add-in on this page. An Outlook add-in lives inside one client and appears when you open it. A mailbox-level agent works whether anyone has Outlook open or not: the 2am enquiry is classified and answered while the office is dark, and the reply is sitting in the thread (sent, or drafted, depending on your mode) when you check in the morning.

From the moment an email lands in your Outlook inbox to the moment a reply goes out, the pipeline looks like this:

1. Classify. Every inbound email is classified automatically (support question, sales enquiry, booking, billing, needs-action) and routed or escalated accordingly. Each email gets handled by the rules meant for its type rather than one generic response. On the Scale plan and above, a custom rules engine and smart auto-filing give you finer control over routing.
2. Answer from your knowledge. Replies are generated only from knowledge you provide: uploaded FAQs, PDFs, CSVs and documents, or your website content. Not generic model guesses: your actual policies, prices and procedures.
3. Apply the right playbook. Playbooks are scoped response brains (each with its own knowledge, tone of voice and constraints), so a booking enquiry and a billing question get handled by different rules, in different voices. A warm, chatty playbook for sales enquiries can sit alongside a precise, careful one for billing, each drawing on its own slice of your knowledge.
4. Escalate what needs a human. Emails that need more than a reply (refunds, escalations, judgement calls) become trackable action items in your team workspace instead of receiving a hallucinated answer.

For the full picture of how the agent model works across Gmail and Outlook, see how the AI email agent works, or read how it compares to hiring an email answering service.

Autopilot, with brakes: how auto-send stays safe

"Is it safe to let AI send from my account?" is the right first question: it's the one every buyer asks, and it deserves a mechanical answer, not reassurance. The honest framing: an AI that improvises answers from a general model should never send email for a business. An AI that can only answer from your own documents, and escalates everything else, is a different machine. InReply is built as the second kind, and the controls below are how you verify that yourself rather than take our word for it.

The connection itself is built to the same standard. InReply uses OAuth with encrypted tokens: no passwords are stored, and you can revoke access from your Microsoft account at any time. It's GDPR compliant and run by a UK company (Strategic Minds Group Limited, London). AI processing runs through OpenAI's API, which under its API terms does not train on your inputs. And if you cancel, your data is permanently deleted within 30 days: your mailbox, and everything already sent or drafted in it, was always yours.

That's why the zero-risk way in is Ghost Mode: every reply is a draft until you say otherwise. You watch real answers to real customer emails appear in your Outlook drafts folder for a week or two, correct anything you don't like, and switch on Autopilot playbook by playbook: FAQs first, sensitive topics last or never.

Copilot for Outlook alternatives, compared (July 2026)

Competitor facts last verified 22 July 2026

Microsoft Copilot is the default for a reason: native drafting and summarising inside Outlook, with deep Microsoft 365 context no third party can match. But it requires paid Microsoft tiers, cannot be bought for Outlook alone (MaestroLabs, retrieved 22 July 2026), and the same review flags its struggles with long or complex threads and its limited tone controls. Above all: it drafts. It never sends.

MailMaestro is an Outlook add-in for drafting, summarising and improving emails, listed at $15/seat/mo in Lindy's roundup (retrieved 22 July 2026). MaestroLabs' own review describes drafting and summarising only: no auto-send is described. A solid choice for personal productivity inside Outlook; not a tool that will answer your customers for you.

Fyxer drafts suggested replies in your voice as messages arrive and connects to both Outlook and Gmail, at $30/user/mo per Lindy's roundup (retrieved 22 July 2026). It's draft-first: a human still sends every email. See our full InReply vs Fyxer comparison and Fyxer AI review.

Lindy is a general AI-agent builder at $49.99/mo per its own listicle (retrieved 22 July 2026): powerful if you want to assemble your own workflows, but build-it-yourself rather than a turnkey inbox product. Budget time for configuration and testing, not just the subscription.

Gmelius is a shared-inbox collaboration tool whose Outlook support is waitlist-only: its homepage said "Start with Outlook (Waitlist is open)" and "Less Email for Outlook is coming…" as of 22 July 2026. Worth watching if you want Gmelius specifically, but not something an Outlook team can deploy today.

Shortwave is an AI-native email client whose homepage advertises Gmail accounts only, with no Outlook support mentioned as of 22 July 2026 ($18/seat/mo per Lindy's roundup).

Jace runs a draft-approval workflow ("Approve drafts instantly"), with no Outlook support advertised on its homepage as of 22 July 2026. See InReply vs Jace and our Jace AI review.

Built for teams sharing one Outlook inbox

Copilot is a per-seat personal assistant: it makes one person faster at their own email. A business inbox (hello@, support@, bookings@) needs something different: one shared agent working the inbox for everyone. Ask how most small teams run a shared Outlook inbox today and the answer is usually a password in a spreadsheet and a vague agreement about who checks it, which is how two people answer the same email and nobody answers the awkward one.

InReply gives you a team workspace where multiple members manage the same inbox with their own accounts: no shared Microsoft credentials, no password in a spreadsheet. Emails that need more than a reply become trackable, assignable action items, so ownership is visible: who's handling the refund, what's still open, what got resolved. A refund request stops being an unread email that everyone assumes someone else saw, and becomes an item with a name on it.

It's also different from Gmelius-style shared-inbox collaboration suites. Those help humans coordinate and send faster. InReply removes the routine sending entirely: the team only sees the emails that genuinely need a person.

Set up in minutes, not a migration

"Migration" is the word that kills most inbox-tool purchases, and rightly so: moving a business inbox is risky and slow. So it's worth spelling out that there is no migration here. Three steps:

1. Connect Outlook: sign in with Microsoft. Secure OAuth, encrypted tokens, no passwords stored, revocable any time. Your mail stays exactly where it is.
2. Upload your knowledge: FAQs, PDFs, CSVs, documents, or link your website. This becomes the only material InReply answers from, organised into playbooks with their own tone and constraints.
3. Start in Ghost Mode: every reply lands as a draft in Outlook for review. Edit what needs editing, send what's right, and switch on Autopilot when you're ready.

You keep Outlook as your client throughout: InReply works behind it. Nothing about how you or your team read email changes; what changes is how much of it still needs you.

Plans start at £39/mo for 500 emails a month (1 inbox, 2 users), with Growth at £79/mo for 2,000 emails and Scale at £149/mo for 5,000, always priced by email volume rather than per seat. Every plan starts with a 14-day free trial, no credit card required, cancel anytime. See full pricing.