Email is a digital hydra. For each one you bat out of your inbox, two others take its place. You finally pass the info on to your co-worker, only to drown in a jet of newsletters. Wouldn't it be great if AI could be your personal email Hercules?

This category has evolved a lot since I first explored it last year. Now you'll find powerful options that'll help you write emails, improve communication, sort through conversations, or burn a stack of junk mail in a flash. This is a lot more compared with the first-wave AI email apps that just integrated with OpenAI for writing drafts and called it a day.

I spent two weeks researching and testing the best AI email assistants, and I've put together a shortlist for you to try out—along with apps you should keep an eye on. And in case you'd like to build your own AI-powered email workflows, I've included a quick breakdown of how this technology can help you do just that.

The best AI email assistants

• Shortwave for AI-powered email search

• Microsoft Copilot Pro for Outlook for improving communication

• Superhuman for mixing AI generation with message templates

• SaneBox for keeping your inbox organized

• Mailbutler for gathering contact details and tasks

What can AI bring to email?

AI has shown us that it can understand and generate human language pretty well. While it's not ready to work unsupervised, it's a great tool to improve your existing automation with the ability to understand language. It can make a few decisions on its own, and it's up to you to accept or edit the results.

But what does this mean when it comes to AI email apps? Let's walk through the main AI features that you can use for automating your inbox.

Generative AI

Right now, the most common use of AI in email apps is for writing messages with generative AI. When composing a new email, you can start from a prompt—pretty much like in ChatGPT—or start generating a reply based on the sender's message text.

Other features here include spell-checking your messages, rewriting with AI, offering quick reply suggestions, or even creating a pre-generated reply that you can send with one click.

Processing email content

Since AI can understand human language, it can analyze the content of each email. It can, for example:

• Run sentiment analysis on the message, providing an overview of how the sender is feeling. This is useful to understand if you need to be more tactful in your reply or if the person on the other side is open to learning more.

• Understand the topic of the email, which you can use to sort incoming messages with tags, labels, or folders. After your emails are organized, you can set up rules to forward each one to the appropriate person or just to sort the list with the highest priority at the top.

• Summarize the email or the entire thread, making it easy to file the conversation to analyze later or to bring new collaborators into the topic.

Data extraction and enrichment

Closely related to content processing, AI can also detect data types in your emails, extract that data, and store it in a database app. There are a lot of possibilities here. You can:

• Extract all the contact data from an email and add it to your CRM.

• Extract an invoice number and update information in your accounting app.

• Extract all the attachments from an email, read the contents of each file, and store them with the appropriate project pages in your project management app.

Data extraction pulls out information from an email. Data enrichment is almost the opposite: it surfaces information from your email history, your connected database apps, and public information to give you context on the current conversation. Imagine you're talking to a friend you've known for 10 years. With data enrichment, you could summarize your entire email history and get some clues on where you should go on vacation next. 

Train your own AI language model to reply for you

You can train a model to contain all the relevant information about you and your business, so you can leverage that training to answer emails—and even produce other kinds of written content, too.

There are two ways to do this right now. If you have money to spare, you can hire a developer to fine-tune an OpenAI model. This is a method of tuning a GPT model with your data, helping it speak like you and know more information about you or your company.

If you're looking for something easier, you can use a tool like Personal AI to train a personal language model rooted in your knowledge and writing style. You can then use Zapier to have it process all your emails and generate new drafts as necessary. Learn more about how you might automate Personal AI to do that.

Combine them all

All of these features can be used with one another. Here's an example:

1. Set up your AI to read everything in your inbox, extract relevant data, run sentiment analysis, and check your tech stack for relevant information.

2. Generate a reply with AI for each message based on the sender's message and your data, organize emails with the most urgent first, and set your inbox to wait for your confirmation before sending. 

3. Pop by your inbox at the end of the day, start with email #1, and check the contextual information and pre-generated reply. If it looks good, hit send, and move to the next one.

And this is barely scratching the surface. The exciting thing about AI and email is that, depending on which features you use and the order in which you use them, you can get a completely different experience and results. It's highly adaptable to each circumstance, meaning it can solve more complex problems—but, at the same time, it may take longer to reach a viable workflow.

To be clear: none of the apps on this list are flexible enough to run a complex workflow like the example above. But if you're willing to tinker, you can use a collection of Zaps to automate your inbox with AI and build a custom solution.

What makes the best AI email assistant software?

Based on all the possibilities that this technology brings to the table, generative AI isn't enough. The best AI email assistant software needs to go a bit beyond that. Here's what I looked for as I was testing all the apps that claimed to be AI email clients. 

• Easy email integration. The integration process should be easy and fast with the most popular email services.

• Inbox management. I prioritized individual inbox management apps. For now, I'm leaving out apps that are focused on sales and outreach or customer service—I'm showing you how AI can transform your personal inbox, whether at home or at work.

• AI features. I was looking for AI features beyond generative text—for example, things like sentiment analysis, intent detection, automatic labeling, or data extraction.

• Productivity and automation. AI is one tool out of many, so these apps should offer other features and settings to help you save time and get to inbox zero faster.

• Data privacy. Your emails are private, so adding an app like this to your collection shouldn't represent a security risk. I read the privacy policy of each app to understand how secure your data will be.

For two weeks, I dug the internet for all the AI email assistants that I could find. I filtered out those that just integrated generative AI into the compose window and was left with a smaller selection. I signed up for each of them, configured the platform until it was ready to use, and sent a few emails back and forth between my email accounts. I played with the settings, observed how well the AI did what I wanted it to, and from there, picked these apps.

The best AI email assistants at a glance

Best AI email assistant for searching email history

Shortwave (Web, Android, iOS)

Shortwave pros:

• Deep integration with Google Calendar

• AI assistant is very flexible

Shortwave cons:

• Interface feels cluttered at times

Sitting confidently on the throne here, Shortwave has the widest range of AI features of all the apps on this list. They all live in the top-right of your screen: click on the magic stars icon there, and a chat window appears docked on the right side. This is the Shortwave AI Assistant.

The most unique possibility it offers is AI-powered email search. You can ask questions to your inbox to surface old, forgotten conversations without actually having to get lost in the mess. More than this, it can extract data from email threads ("make a list of all the tasks in the website redesign project"), generate content ("write a tweet based on my emails about productivity"), or answer your questions ChatGPT-style.

Email and calendars usually go hand in hand. In Shortwave, you can schedule meetings or new events in natural language, with something as simple as "schedule a meeting for me and John in 2 days at 6pm." I used this exact prompt, and the meeting appeared on my calendar. I didn't have to do anything else. And if you don't know your availability, just ask, and you'll get a breakdown of your open slots for the near future.

The bulk of these AI features live in the sidebar, but you can see them in the email interface as well—look for the magic stars. While opening an email, look under the subject: you'll see a short generated summary of the thread. If you click on it, it'll work on a longer, more thorough version. A real time-saver if there's a lot of back and forth or multiple people involved in the conversation.

And then, on the right side of where you write your replies, there are the magic stars again: you can generate a message from scratch or based on a prompt. This takes the action back to the sidebar, but you can easily add the AI output to a new reply and keep the conversation flowing.

A bit of disappointing news: Shortwave only works with Gmail accounts for the time being, so if you're doing email with other providers, you'll have to sit out. Here's hoping it'll integrate with more inboxes in the future.

Shortwave price: Personal starts at $8.50/user/month

Best AI email assistant for improving communication

Microsoft Copilot Pro for Outlook (Windows, Mac, Android, iOS)

Copilot Pro for Outlook pros:

• OpenAI's GPT-4 available

• Also unlocks AI features in your other Office apps

Copilot Pro for Outlook cons:

• No integration with non-Microsoft email inboxes

Microsoft's AI expansion continues with the release of Copilot Pro. Outlook is one of the apps that gets a boost, with three shiny AI features that, while not groundbreaking, are really well-implemented and easy to use. And, since we're talking about a tech giant, this list could expand quickly.

The first one is straightforward: you can write emails from scratch using AI. When writing a new email, look to the right half of the toolbar, click on the Copilot icon, and select Draft with Copilot. That will open the settings, where you can type your prompt, set the tone and length, and then start generating.

The second one is thread summarization: like others on this list, you can get a big-picture view of a conversation in a list of topics. Unlike others on this list, Copilot adds little numbers in superscript that you can use to jump to the message where that topic is discussed. Super helpful for searching your conversations for specific statements.

But the last one really surprised me. Called Coaching by Copilot, you can have your email message analyzed to see how the tone, content, and structure of the email will impact the receiver. I wrote a general project kickoff email to test this, and it told me I could be more enthusiastic, show appreciation for the reader's contribution, and break down the topics for higher clarity. This comes with a few example sentences, so you know how to take the first steps. A well-written email can save you a lot of headaches along the way, so I find this very helpful to manage projects, provide updates, and make communication more effective.

Outlook wraps it up with a nice touch: if you generate an email with AI and click to send right away, it'll show a pop-up reminding you that AI may be inaccurate, inviting you to revisit the content before pushing it out.

And, of course, this isn't the only place where you'll be getting AI. You'll also get Copilot features to help write documents in Word, generate presentations in PowerPoint, and analyze data in Excel. Plus, you can integrate Microsoft Outlook with Zapier to connect it to all the other apps you use at work. Learn more about how to automate Outlook, or get started with one of these pre-made workflows.

Important: Copilot only works with email addresses ending in Microsoft-related domains, such as @outlook.com, @live.com or @hotmail.com. This may be related to privacy policy reasons. For example, I wasn't able to get it to work with a Gmail account. And while we're talking about privacy, it isn't very clear if, as a personal user, your data will be used for training or fine-tuning models. For companies, the data governance settings you have in place will apply when dealing with Microsoft's LLMs, except if you're using plug-ins or internet-connected generation.

Microsoft Copilot Pro price: Microsoft 365 subscription required, starting at $9.99/month; AI features go for $20/month.

Best AI email assistant for mixing AI generation and message templates

Superhuman (add-on)

Superhuman pros:

• Split your inbox by topics to organize messages

• Powerful keyboard shortcuts

Superhuman cons:

• Not as many AI features as the other options

AI saves time when writing emails, but it might fail to produce the exact results you're looking for. This is especially true if you've crafted the perfect outreach email or the ideal company presentation paragraph. Superhuman will help you balance both: the speed of AI generation and the precision of your existing messaging.

As a keyboard-driven app, you'll have to learn the shortcuts to move around quickly. This adds a bit of a learning curve at the start, but it'll feel great once you grasp the basics. Let's walk through the process of writing a new email with AI and your templates:

1. When reading an incoming email, press Enter to reply. 

2. Start by generating with AI: hit Ctrl + J, write a short prompt, and send it. 

3. Then, you can use the snippets feature to add pre-written blocks of text: click anywhere on the message, tap the ; key, and select the one you want. It'll land exactly on that part of the email.

While Superhuman comes with a few stock snippets, you'll need to add your own. Head to the Snippets screen (click the hamburger menu, and select Snippets, or hit G followed by ;), and add as many private or team snippets as you need. They can be full messages with attachments or short blocks of text detailing a product or service you offer. You can customize them with variables, so the fields update based on the message sender.

On top of this generative AI tool, you'll be able to summarize any of your email threads: hit M while reading to do so. A small collection of AI features, yes, but so well put together that it deserves a shout on this list—especially since Superhuman is already such a strong product. The user interface is minimalist, offering tools to split your inbox based on email types and a way to mark your emails as done, useful for tracking what's still to do.

Caveat time: look at that price tag. All this could be yours for $30 per user per month. Steep, I know. But if you love a polished user experience that turns email into a mini-game, you'll be happy with how much Superhuman can make the road to inbox zero fun again.

Superhuman price: $30/user/month

Best AI email assistant for keeping your inbox organized

SaneBox (add-on)

SaneBox pros:

• Very hands-off after setup

• A SaneLater folder for low-priority emails

SaneBox cons:

• The interface is pretty dated; doesn't instill a lot of confidence

SaneBox is really lo-fi. It sits in the background doing its thing. Once you go through onboarding and finish tweaking the settings, you won't have to constantly log in to it. You can just use your inbox normally (on any client or device), and it will keep working.

When you start the configuration process, you can list the labels you'd like to use or have SaneBox do that for you. It'll go through your inbox to weed out newsletters, conversations with friends and family, system messages from the apps you use, and a lot more. Once you finish running it, a few things will happen:

• You'll see all your emails split by category, and you can easily trash useless messages (for example, email notifications from your apps).

Then, after that deep clean is complete:

• The important emails will stay in your inbox, so you can focus your attention on them first.

• All lower-priority emails will be added to the SaneLater folder. You can visit it once per day to read everything. It's best to visit it frequently during the first weeks of using SaneBox: it's still training, and its accuracy will improve over time. You can help train the model by dragging unimportant emails from your inbox to the SaneLater folder.

• You can create folders for any kind of topic or group of people, drag emails into those folders, and SaneBox will pick up on your intentions. It'll start funneling similar emails in the future.

If you're getting a lot of annoying messages from a single sender, you can throw them into the SaneBlackHole: it'll get all follow-up emails into its gravitational pull, so you'll never hear from that person or organization again.

All these AI-powered sorting features will make sure that your attention will always be on your critical emails, keeping your inbox clean and organized throughout the day.

SaneBox price: From $0.07/day (or $24/year) for 1 feature on the Appetizer plan. If you want more than one email account and more than 2 features, you'll need at least the Lunch plan, which is $12/month (or $169/24 months).

Best AI email assistant for gathering contact details and tasks

Mailbutler (add-on)

Mailbutler pros:

• Data extraction from email signatures

• Task extraction, plus integration with task management apps

Mailbutler cons:

• Only works in Gmail, Apple Mail, and Outlook

Mailbutler went deep in integrating generative AI into its compose window. But it goes a little further too: it keeps your contact information complete and picks up on tasks mentioned in your emails, two features that set it apart from the competition.

It works as either a Chrome extension, Apple Mail extension, or Outlook add-in. It adds a sidebar to your inbox, letting you access the extra features there. You can access your contacts, notes, and tasks, as well as the contextual actions you can take when viewing an email.

Let's start with data extraction. Mailbutler looks at the signatures of all emails you receive to grab phone numbers, addresses, and positions within a company. You can add extra fields if you'd like to, helping you keep a complete record of everyone you're talking to.

In addition to signatures, it also processes the text of the emails looking for tasks, adding them on the sidebar so you won't forget them. And since the app integrates with task management apps, you can send them straight over without having to retype anything.

The generative AI features are quite complete, too:

• Smart Compose writes an email for you from a prompt.

• Smart Respond lets you generate a positive or negative reply.

• Smart Summarize turns a long-winded email into a snappy snack.

• Smart Improve keeps your grammar and spelling in check.

And all of this on top of a collection of useful features such as email open tracking, rich signatures, scheduled sends, team collaboration, and email snooze. 

Mailbutler price: From $4.95/month, but AI features are only available starting at the Smart plan for $14.95/month.

Other AI email assistants to watch

There are a few AI email apps that didn't quite make it due to my strict criteria, but I'd still like to share them with you. As they grow, they may incorporate more AI features or become better for personal inbox management, so definitely keep an eye out for them.

• Google Gemini joins the competition, bringing AI features to Google Workspace users. It only offers generative AI for writing emails in Gmail for now. I'm sure it'll get a lot of love in the future, so be sure to keep up to date with this one. Learn more about Google Gemini.

• Mailytica leans customer service, using AI to handle repetitive emails at scale. You'll have your own model trained with your company's messages, access email classification, email reply suggestions based on blocks (not on generation), sentiment analysis, and plenty of advanced features to save time and improve consistency.

• EmailTree used to be part of this list, but the pricing now is a better fit for customer support teams juggling email and Zendesk tickets. It offers AI and advanced automation features to help you tackle emails quickly and accurately.

Put your email on autopilot

I love the inbox zero feeling. I confess I've been having it less and less, so it's time to side with the bots. Having AI in your inbox means you'll be able to be more agile with important messages, handle the lower-priority ones gracefully, and throw the rest out the window.

While we're still waiting for more competition when it comes to AI email assistants, the apps above are a good start. You can also create your own AI email workflows using Zapier. Learn more about how to use GPT to automatically write business emails, sales emails, or email summaries with Zapier and OpenAI. Or get started with one of these pre-made workflows.

Related reading:

• 6 ChatGPT prompts that will generate great sales emails

• How a contractor with dyslexia uses AI and Zapier to write business emails

• The best AI scheduling assistants

• Shortwave vs. Superhuman: Which should you use?

This article was originally published in September 2023. The most recent update was in March 2024.