FlowCrypt

Overview

FlowCrypt is an email encryption service built around a browser extension, with other platforms and a mobile application also offered. It suits individuals who want to send protected mail from Gmail or Outlook, as well as larger organizations that need centralized security rules. Its flexible recipient options are a strength; the split between two stated free attachment limits and custom enterprise pricing complicates the buying decision.

FlowCrypt is operated by FlowCrypt a.s., headquartered in Prague, Czech Republic. The company’s founding year is given as 2015, while it is also described as having existed since 2016.

For category comparisons, see Email Encryption Software and File encryption tools.

Key features

• Two ways to reach recipients: FlowCrypt sends encrypted messages to OpenPGP users and password-protected messages to others. That makes it useful when correspondents do not share the same encryption setup, though recipients use different delivery routes.
• Secure replies: Recipients can reply securely without installing a plugin, a practical advantage for one-off or external conversations.
• Email integration and delivery controls: Gmail and Outlook integration are supported. Messages can expire, recipient verification uses a password, and secure delivery is provided by link.
• Enterprise administration: Administrators can set domain-wide settings and restrictions, including rules for passphrases, keys, signing and other security requirements. This is more relevant to managed domains than to solo users.
• Authentication and systems integration: Enterprise supports SSO through Google, OIDC providers and delegated IdPs, and can connect with public key servers, HSMs and internal systems. The enterprise DPA is described as GDPR-compliant, and support includes an SLA for availability and response times for fixes and patches.
• Scale: Enterprise supports domains with more than 100 users, placing its commercial offering toward larger organizations rather than small teams seeking a published per-seat price.

Pricing

FlowCrypt uses a freemium model. The Free plan costs nothing and is for fewer than 100 users. Its plan summary gives a 5 MB attachment threshold, while the free-plan description says free users can attach files up to 25MB. Those limits conflict, so users who regularly send larger files should confirm the applicable cap before relying on the free tier.

Enterprise has custom pricing: organizations must contact FlowCrypt for commercial-use pricing. It supports more than 100 users per domain and attachments up to 25 MB, along with domain controls, custom security rules, SSO, systems integration and an SLA. The absence of a published price means buyers cannot compare its cost per seat without contacting the company.

The Free plan is the clear starting point for individual use and smaller groups that can work within its attachment allowance. Larger domains needing policy enforcement and enterprise authentication should consider Enterprise, but should get both pricing and attachment terms confirmed directly.

Platforms

FlowCrypt is offered as a Chrome extension, with other platforms and a mobile application also available. The listed email integrations are Gmail and Outlook. This combination will suit users who want encryption alongside those email services, but the extension remains the specifically identified platform.

Who it's for

FlowCrypt is a sensible fit for individuals sending encrypted email to OpenPGP users and for correspondents who need a password-protected alternative. Secure replies without a plugin help when recipients are not regular users of encryption software.

It is also a candidate for organizations with more than 100 users per domain that need administrators to enforce security settings or integrate authentication and internal systems. It is less suited to buyers who require transparent commercial pricing before evaluation, or to free users who cannot resolve which attachment cap applies.

Pros and cons

• Pro: Works across recipient types. OpenPGP messaging and password-protected delivery cover correspondents with different setups.
• Pro: Secure replies do not require a plugin. External recipients can continue a protected exchange without installing one.
• Pro: Enterprise policy and integration options are substantial. Domain-wide controls, custom rules, SSO and connections to HSMs or internal systems support managed deployments.
• Con: Free attachment limits are inconsistent. The Free plan summary says 5 MB, while the free-plan description says up to 25MB.
• Con: Enterprise pricing requires direct contact. Organizations cannot assess the commercial cost from a published rate.

Alternatives

Mailvelope is another freemium extension option, also offered on the web, with a free trial and a Mailvelope Business plan priced at €3 a month for 1–49 users. It is worth comparing when a published monthly business price matters.

c.Email is a free extension offering unlimited email addresses. It may suit readers whose priority is a free plan without an address-count cap.

SecureMyEmail has a free plan for one email address and supports Windows, macOS, iOS and Android. It is a better comparison for readers looking for named desktop and mobile platforms.

DataMotion Secure Email Exchange is an enterprise offering with a free trial and Android, iOS, web and API platforms. Consider it when those platform options are a priority.

Send It Secure offers Guest, Essentials and Professional plans. Compare it when choosing among its plan options.

Lockbin has a free plan for one user with a 25 MB attachment limit and six months of inbox storage, plus a Premium plan at $10 a month. It is a useful comparison for an individual who wants a stated free attachment limit and storage period.

gpg4o is a Windows option with a free plan and a paid OpenPGP product supporting Microsoft Outlook 2016, 2019, 2021 and 365 Classic. Consider it when Windows and those Outlook versions are central requirements.

Gpg4win is a free Windows alternative.

Verdict

FlowCrypt is best for individuals who need encrypted email with flexible recipient handling, and for large domains that can use its administrative controls and integrations. Choose it for the combination of OpenPGP messaging, password-protected delivery and enterprise policy options. Look elsewhere if you need a clear enterprise price up front or cannot accept uncertainty about the free attachment cap.