Software Alternatives & Startups

Customer.io VS Sortfully

Compare Customer.io VS Sortfully and see what are their differences

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Customer.io logo Customer.io

We make it easy to send emails triggered by user behavior. Build, measure and improve your emails to activate and retain users

Sortfully logo Sortfully

Auto-file your Outlook & Microsoft 365 mail by the organisation that sent it - once you've read it. Sortfully never reads your message bodies or attachments.
  • Customer.io Landing page
    Landing page //
    2023-10-08
  • Sortfully Dashboard
    Dashboard //
    2026-08-31
  • Sortfully Mappings View
    Mappings View //
    2026-08-31

Sortfully is an automatic filing service for Outlook and Microsoft 365. It moves each message into an Inbox subfolder, or tags it with a coloured category, based on the organisation that sent it. By default a message is only filed once you have read it, so new mail still lands in front of you and nothing disappears unseen. If you prefer, filing can happen instantly on delivery instead.

There is no AI in Sortfully. No model, no classifier, no LLM, and your mail is never sent to any AI service. Filing runs on deterministic rules you can read and edit: the sender's domain, your exact-match overrides, then Public Suffix List normalisation, so notifications.slack.com and hello@slack.com both land in one Slack folder, and .co.uk domains get correct names. You can group several domains into one folder, pin a domain to a folder you already have, exclude senders entirely, and choose move-or-tag per organisation. Every action is reversible.

Privacy is structural, not a promise. Sortfully never reads message bodies or attachments: the one code path allowed to call Microsoft Graph message endpoints uses a strict metadata field allow-list, and a CI gate fails the build if a content field ever appears. An optional detailed audit log records the subject line so you can see exactly what was filed; you can switch it off. Sortfully connects through delegated Microsoft Graph permissions only (Mail.ReadWrite, Mail.ReadWrite.Shared, MailboxSettings.Read), is a verified Microsoft publisher, and reads your existing inbox rules without ever modifying them. Tokens are encrypted at rest and you can disconnect at any time.

Optionally, a chunked, throttle-safe backlog cleanup sorts the mail you already have, with protected folders and a leave-recent-mail window so nothing current is touched.

Sortfully is built for Microsoft 365 first: individual mailboxes, shared mailboxes, and a Business plan with team management for firms. It is operated by a UK company, hosted in the EU.

Sortfully

$ Details
paid Free Trial £5 / Monthly
Platforms
Web SaaS Outlook
Release Date
2026 August
Startup details
Country
United Kingdom
City
London
Founder(s)
Adam Harman
Employees
1 - 9

Customer.io features and specs

  • Powerful Segmentation
    Customer.io allows for highly detailed segmentation of your customer base, enabling personalized and targeted messaging.
  • Behavioral Targeting
    You can trigger automated messages based on user behavior and events, ensuring timely and relevant communication.
  • Flexible API
    Customer.io offers a robust and flexible API, allowing for seamless integration with your existing systems and workflows.
  • Customizable Workflows
    The platform provides the ability to create complex workflows for customer journeys, which helps in automating multi-step processes.
  • A/B Testing
    Customer.io offers A/B testing capabilities for emails and messaging, enabling the optimization of your communications strategy.
  • Analytics and Reporting
    The tool includes comprehensive analytics and reporting features to track the performance of your campaigns and make data-driven decisions.

Possible disadvantages of Customer.io

  • Price
    Customer.io can be expensive, especially for smaller businesses or startups with limited budgets.
  • Learning Curve
    The platform has a steep learning curve, and new users might find it challenging to utilize all features effectively without proper training.
  • Limited Native Integrations
    Compared to some competitors, Customer.io has fewer native integrations, which may require additional development work to integrate with other tools.
  • Complexity
    Due to its extensive features, the platform can become complex to manage, especially for users who only need basic email marketing functionality.
  • Support Limitations
    Customer.io has limited support options for lower-tier plans, which might be a challenge for users needing more hands-on assistance.
  • Visual Workflow Builder
    While powerful, the visual workflow builder can sometimes be less intuitive compared to similar tools on the market, potentially slowing down the creation process.

Sortfully features and specs

  • Filing by sender organisation
    Mail is filed by the organisation that sent it, so every alias and subdomain from a company lands in one folder.
  • Move or tag per organisation
    Each organisation can be moved to an Inbox subfolder or tagged in place with a coloured category.
  • File after read
    By default nothing moves until a message has been read, so new mail never disappears unseen; instant filing on delivery is optional.
  • No AI
    No model, no classifier, no LLM; filing runs on deterministic rules you can read and edit, and mail is never sent to any AI service.
  • Content-Blind
    Message bodies and attachments are never read, enforced by a code-level allow-list and a CI gate, not just a policy.
  • Public Suffix list
    Public Suffix List normalisation gives correct names for .co.uk, .energy and hundreds of other endings.
  • Overrides and exclusions
    Group several domains into one folder, pin a domain to an existing folder, or exclude senders entirely; your rules always win.
  • Backlog cleanup
    Sorts the mail you already have in chunked, rate-limited passes, with protected folders and an option to leave recent mail in place.
  • Undo anything
    Every filing action is recorded and reversible from the dashboard or audit log.
  • Audit Log
    A record of every filing with sender, destination and mode; a detailed option records the subject line and can be switched off.
  • Shared Mailboxes
    Files shared mailboxes a delegate has access to, alongside personal ones.
  • Team Management
    The Business plan adds team management for firms running multiple mailboxes with multiple users.

Analysis of Customer.io

Overall verdict

  • Customer.io is considered a good choice for businesses that need a powerful and customizable marketing automation tool. Its strength lies in its ability to deeply integrate with other data sources and respond to user behavior in real-time, providing a highly personalized marketing experience.

Why this product is good

  • Customer.io is a marketing automation platform designed to create personalized email campaigns and automate various customer interactions. It offers robust segmentation, A/B testing, and behavioral tracking, making it suitable for businesses looking to deliver targeted communications based on user actions and data. Its intuitive interface and flexibility have made it a popular choice among marketers.

Recommended for

  • Businesses with a strong need for behavioral-driven marketing campaigns.
  • Companies with a technical team that can handle integrations and customizations.
  • Marketers looking to deliver personalized and timely emails based on user activity.

Customer.io videos

Intercom vs Customer.io vs Zendesk Connect? What's the Best Tool?

More videos:

  • Review - Get to know Customer.io
  • Review - Colin Nederkoorn, CEO of Customer.io, on why knowing your customers is the key to growth

Sortfully videos

No Sortfully videos yet. You could help us improve this page by suggesting one.

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Category Popularity

0-100% (relative to Customer.io and Sortfully)
Email Marketing
100 100%
0% 0
Inbox Management
0 0%
100% 100
Email Marketing Platforms
Email Automation
0 0%
100% 100

Questions & Answers

As answered by people managing Customer.io and Sortfully.

Why should a person choose your product over its competitors?

Sortfully's answer:

Most email organisers ask you to trust them: an AI classifier scores your mail and a privacy policy promises restraint. Sortfully is built so you don't have to take its word for it. It cannot read message bodies or attachments; the restriction is a code-level allow-list backed by a CI gate that fails the build, and filing runs on deterministic rules you can read and override. It is also the only one of its kind built for Outlook and Microsoft 365 first: delegated Microsoft Graph permissions from a verified Microsoft publisher, shared mailbox support, and read-only respect for your existing inbox rules, where SaneBox, Clean Email and Mailstrom treat Outlook as a second platform. And it behaves differently: mail is filed by sender organisation, so every alias and subdomain lands in one folder, and by default only after you have read it, so nothing disappears unseen and everything can be undone.

What's the story behind your product?

Sortfully's answer:

Sortfully was built by a UK founder who watched Outlook rules fail at scale: Exchange caps rules at 256 KB, one rule per sender domain does not scale, and rules only run while Outlook is open. The alternatives all wanted AI access to mail content, which is exactly what regulated firms cannot accept. So Sortfully does the opposite: deterministic filing by sender organisation, with a code-enforced guarantee that message bodies and attachments are never read. It launched in August 2026, operated by a UK company with EU hosting.

What makes your product unique?

Sortfully's answer:

Sortfully contains no AI at all. Filing runs on deterministic rules you can read and edit: the sender's domain, your overrides, then Public Suffix List normalisation. And the privacy guarantee is structural rather than promised: the one code path allowed to call Microsoft Graph message endpoints uses a strict metadata allow-list, and a CI gate fails the build if a content field ever appears. Message bodies and attachments are never read.

How would you describe the primary audience of your product?

Sortfully's answer:

Businesses and normal consumers can both benefit from Sortfully. Businesses on Microsoft 365, mainly professional services firms of 10 to 200 mailboxes (accountants, solicitors, surveyors, architects) and the IT admins or MSPs who manage their tenants. It also suits compliance-conscious firms that have decided against AI email tools, and individual Outlook power users.

Which are the primary technologies used for building your product?

Sortfully's answer:

Laravel (PHP), PostgreSQL and Redis on the backend; React with TypeScript and Inertia on the frontend; the Microsoft Graph API with delegated permissions for all mailbox access. Hosted in the EU.

User comments

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Reviews

These are some of the external sources and on-site user reviews we've used to compare Customer.io and Sortfully

Customer.io Reviews

15 best user onboarding software you need to try in 2023
With a focus on messaging, Customer.io lets you create sales workflows around various pushes and nudges, across a range of channels. Email, SMS messages, and push notifications can all be built into an engagement campaign designed to pique curiosity.
15 Mailchimp Alternatives for SaaS Companies
What's more, Customer.io offers advanced automated or API-triggered workflows and various advanced functionalities like time delay or time windows to ensure that you reach customers at the best time for them to take action.
Source: userlist.com
"Pay 880$ per month" - Intercom
Did you find any good option in place of customer.io ? As customer.io seems very expensive once your contact numbers increase.
The 36 Best Marketing Automation Tools to Use in 2020
Some tools like Customer.io, Autopilot, and Encharge merge the gap between marketing and transactional emails and provide a cohesive platform to automate the whole customer journey from a lead to an active user. However, there are platforms like Sendgrid and Mailgun that focus specifically on transactional emails. These infrastructure platforms are usually used by developers...
Source: encharge.io

Sortfully Reviews

We have no reviews of Sortfully yet.
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Social recommendations and mentions

Based on our record, Customer.io seems to be more popular. It has been mentiond 28 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.

Customer.io mentions (28)

  • Dunning Emails – Definition, Examples, Best Practices, and Automation Tools
    If you already use a customer engagement platform like Intercom or Customer.io, you might integrate failed payment events there and use their messaging capabilities. - Source: dev.to / over 1 year ago
  • Self-hostable SMS automation
    I just added SMS as a messaging channel to Dittofeed (MIT licensed customer.io alternative). Source: almost 3 years ago
  • Is this a good use case for Autogpt ?
    Sounds like you need good old automation. Zapier, customer.io, pipedream are some. Source: over 3 years ago
  • MarTech Edge Interview with Jason Lyman, Chief Marketing Officer, Customer.io
    Since joining Customer.io, I have focused on getting to know our ideal customer profile, assessing the competitive landscape, and understanding current market trends. These insights have allowed me to revamp marketing's objectives and set clear goals for the year. I'm looking forward to leveraging what I've learned in past roles to mature the marketing function at Customer.io, better support our customers, and... Source: over 3 years ago
  • Newsletter or phishing?
    Looks like Notion uses customer.io for emails, so probably just a basic marketing/newsletter emails from Notion. Source: over 3 years ago
View more

Sortfully mentions (0)

We have not tracked any mentions of Sortfully yet. Tracking of Sortfully recommendations started around Aug 2026.

What are some alternatives?

When comparing Customer.io and Sortfully, you can also consider the following products

HubSpot - Grow Better With HubSpot: Software that's powerful, not overpowering. Seamlessly connect your data, teams, and customers on one CRM platform that grows with your business.

Sanebox - SaneBox is a cloud-based service that allows users to filter and manage their emails.

Brevo - Innovative online Email Marketing solution to manage your contacts, create & send your newsletters and track your results. More than 80 000 clients. Best prices and attractive features.

Clean Email - Clean Email is an online service that empowers you to take control of your mailbox.

MailChimp - MailChimp is the best way to design, send, and share email newsletters.

Mailstrom - The smarter, faster way to clean out your inbox. Power through thousands of messages in just a few clicks. Free Trial! Website. JOBS.