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Sovereign communication with Expresso V4

Brazilian open-source suite for email, calendar, directory and collaboration, adopted by public agencies, to replace Microsoft 365 and Google Workspace — with data sovereignty, high availability and no per-user license, deployed and maintained by OpenTechs.

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EmailCalendarCollaborationData sovereigntyHigh availabilityNo per-user license

What it is

What Expresso V4 is and why it is strategic

Expresso V4 is an open-source communication and collaboration suite developed in Brazil that brings together in a single platform what your organization needs to work: corporate email, shared calendar, contacts and directory catalog, messaging and collaboration tools — all accessible by webmail and mobile devices.

Born and matured in the Brazilian public sector, Expresso V4 is already adopted by public agencies that needed a national, auditable and independent alternative to proprietary suites. It is the foundation on which institutions build communication that remains under their own control.

Migrating from M365 or Google Workspace to Expresso V4 means two concrete things for the decision-maker: data sovereignty — your messages and calendars no longer live in the cloud and jurisdiction of a foreign vendor — and the end of per-user cost, which grows linearly and unpredictably with each new hire. OpenTechs deploys, migrates and maintains the entire operation.

Sovereignty and recurring savings: with Expresso V4 you eliminate the per-mailbox monthly fee and start operating on an open-source platform on your own infrastructure. In organizations with hundreds or thousands of users, ending the per-user cost of M365/Google Workspace usually pays for the project in the first year — and the savings repeat every year thereafter.
Architecture

Expresso V4 deployment architecture

Expresso V4 is designed to run on your own infrastructure — on-premise or in a sovereign cloud — with end-to-end high availability. OpenTechs sizes, deploys and maintains the environment according to your mailbox volume and continuity requirements.

Sovereignty

On-premise / sovereign cloud

Clients access via webmail and mobile the Expresso application layer, which orchestrates the email, calendar and storage services — all within your infrastructure and your jurisdiction.

Web / Mobile clients — webmail and apps
↕ HTTPS / IMAP / CalDAV
Expresso Application Layer
↕
Email · Calendar · Storage
Continuity

High availability

The services run on redundant nodes, with a replicated database and edge protection, eliminating the single point of failure and keeping communication up even during maintenance.

Redundant appMultiple active nodes
Replicated databaseSynchronous replica
Antispam / AntivirusEdge protection
Integrated backup (NG Backup) + load balancing

On-premise or sovereign cloud?

  • On-premise — when you want the data physically in your data center, under the full control of the internal team and your security policy.
  • Sovereign cloud — when you prefer managed infrastructure in national territory, with the same legal sovereignty, without maintaining your own hardware.
  • Hybrid — Expresso V4 lets you combine them: on-premise production with contingency in a sovereign cloud for Disaster Recovery.
How it works

How we deploy Expresso V4

Planning and sizing

We survey the number of mailboxes, email volume, retention requirements and integrations with your directory (LDAP/AD). From this, we size the application, database and storage infrastructure with room for growth.

Deployment in high availability

We deploy Expresso V4 in an HA architecture: redundant application, replicated database, antispam/antivirus at the edge and integrated NG Backup — so communication does not stop and data is always protected.

Migration of mailboxes and calendars

We carry out the migration of mailboxes, contacts and calendars coming from M365, Google Workspace or Zimbra, with planning, end-to-end validation and minimal disruption for the end user.

Maintenance and 24x7x365 support

After the cutover, OpenTechs takes over the operation: monitoring, updates, hardening, adjustments and 24x7x365 support in English, with an SLA, so your team can focus on the business.

How to engage

From the project to ongoing operation

Expresso V4 is open source: there is no per-user license. What you contract is the OpenTechs service — deployment, managed migration and maintenance — at the level suited to your team’s maturity and the criticality of the operation.

Deployment

Those with their own operations team
  • Complete Expresso V4, deployed and configured
  • Antispam and antivirus at the edge
  • Integration with the LDAP/AD directory
  • Knowledge transfer to the team

Managed Migration

Leaving M365 / Google · recommended
  • Migration of mailboxes and calendars with minimal disruption
  • Source in M365, Google Workspace or Zimbra
  • High-availability architecture (HA)
  • Support with an SLA during and after the cutover

Full Maintenance

Critical managed operation
  • Everything in Managed Migration
  • Continuous operation and monitoring of the environment
  • 24x7x365 support in English, with an SLA
  • Managed evolution, updates and hardening
How the numbers add up: you swap the per-user monthly fee of M365/Google Workspace for a predictable service on a platform with no per-mailbox license. The more users, the greater the savings — and they repeat every year.
Comparison

Expresso V4 vs. M365 / Google Workspace

Criterion M365 / Google Workspace Expresso V4 (OpenTechs)
Cost per user Monthly fee per mailbox, rising No per-user license
Data sovereignty In the vendor’s cloud Full, on your infrastructure
Data jurisdiction Foreign, subject to external laws National, under Brazilian law
Vendor lock-in High, proprietary formats and cloud None — auditable open source
Customization Limited to what the vendor allows Full, adaptable open-source code
Local support Limited, outsourced 24x7x365 OpenTechs, with an SLA
Use cases

Where Expresso V4 delivers value

Government and public sector

Agencies that need a national, auditable and independent suite, aligned with public software policy and state sovereignty.

Sovereignty requirement

Companies and institutions required to keep communication data under national jurisdiction and out of foreign vendors’ clouds.

M365 cost reduction

Organizations pressured by the per-user monthly fee of M365/Google Workspace seeking recurring savings without losing functionality.

Environments with strict LGPD

Operations with sensitive personal-data processing that require full control over where and how email and calendars are stored.

Large organizations

Thousands of mailboxes in high availability, with a replicated database, integrated backup and support with an SLA for critical operation.

Educational institutions

Universities and education networks that need to serve many users with a low per-mailbox cost and full control of the environment.

For the business

What changes for leadership

  • Data sovereignty — email and calendar on your infrastructure, under your jurisdiction.
  • End of per-user cost — no per-mailbox monthly fee; savings grow with the user base.
  • LGPD compliance — full control over where and how personal data is processed.
  • Strategic independence — no lock-in to a foreign vendor or its cloud.
  • Integration with backup and virtualization — integrated NG Backup and operation on Proxmox/ProxVE.
  • Support in English — 24x7x365, with an SLA, from those who deployed the environment.
FAQ

Frequently asked questions

Can I migrate from M365/Google without losing emails and calendar?
Yes. We carry out the migration of mailboxes, contacts and calendars coming from M365, Google Workspace or Zimbra with planning, end-to-end validation and minimal disruption — preserving email history and calendar appointments.
Does Expresso V4 run in high availability?
Yes. We deploy it in an HA architecture: redundant application, replicated database, antispam/antivirus at the edge and integrated NG Backup, eliminating the single point of failure and keeping communication up during maintenance.
Do my users access it via webmail and mobile?
Yes. Expresso V4 offers full webmail in the browser and access from mobile devices via standard email and calendar protocols, without depending on proprietary applications.
Does Expresso V4 integrate with my directory?
Yes. Authentication and the user catalog integrate with your corporate directory via LDAP/AD, reusing the identity base and the policies you already maintain.
Does OpenTechs maintain the operation after deployment?
Yes — we offer full maintenance with monitoring, updates, hardening and 24x7x365 support in English, with an SLA, so your team can focus on the business.

Shall we assess your migration to Expresso V4?

Get an assessment of your current email environment and an estimate of the savings from leaving M365/Google Workspace. No obligation.

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Disponível em: pt-brPortuguês (Portuguese (Brazil))enEnglishesEspañol (Spanish)