Open-source alternative to Office for the web

Open-source alternative to Office for the web: the short answer

If a Microsoft 365 renewal, a licensing change or a data residency rule has put Word, Excel and PowerPoint for the web in question, the main self-hosted answers are Collabora Online and ONLYOFFICE Docs. Both are browser editors that you run on your own servers, and both plug into a file platform such as Nextcloud, so users keep working in the same place they store files. Neither is a drop-in copy of Office for the web, so the decision depends on how well each one renders your actual documents. Fidelity has to be tested per document, not assumed from a feature list. Collect a representative set of .docx, .xlsx and .pptx files from the teams that use them most, including templates with tracked changes, complex tables, charts, macros, embedded fonts and custom slide masters. Open each file in both editors, compare layout, pagination, formulas and comments against the Office original, and record which defects are acceptable. Ask each vendor which formats are native and which are converted, because conversion is where most surprises appear.

The editions differ mainly in what they require from you. Collabora Online's code is under the Mozilla Public License 2.0, and its free CODE edition is described by Collabora as not recommended for production, so a production deployment usually means the paid Collabora Online edition for support, service levels and signed security updates. ONLYOFFICE Docs Community Edition is AGPL-3.0 licensed, while the Enterprise Edition adds an admin panel, white labeling and tiered support, and the Developer Edition is a commercial license for software vendors that embed the editors in their own services. Confirm current terms, user limits and support tiers directly with each vendor before you compare quotes.

Which web editing capabilities map to which open-source option

This table maps the web editing capabilities most teams check during a Word, Excel and PowerPoint replacement to Collabora Online and ONLYOFFICE Docs. Read each row as a question to answer in your own tests, not as a guarantee, because editor feature coverage changes between releases. The main takeaway is that both editors cover core document, spreadsheet and slide editing, while Office add-ins, complex macros and some desktop-only features need a separate check before you commit.

Capability	Collabora Online	ONLYOFFICE Docs (Community and Enterprise)
Word document editing	Edits .docx and ODF text documents in the browser, built on LibreOffice technology. Test complex layouts, tracked changes and comments against your templates.	Native .docx editing in the browser. Community and Enterprise share the core editor. Test tracked changes and comments against your templates.
Spreadsheet calculation	Edits .xlsx and ODF spreadsheets. Confirm that your formulas, pivot tables and charts recalculate as expected in your largest workbooks.	Native .xlsx editing. Confirm formula coverage, pivot tables and charts with your own workbooks before rollout.
Presentation editing	Edits .pptx and ODF presentations. Check animations, transitions, embedded media and master slide layouts against real decks.	Native .pptx editing. Check animations, transitions and master layouts against real decks.
PDF editing	Confirm PDF viewing and editing scope in your target release. Do not assume the same PDF features as the Word, Excel or PowerPoint editors.	Includes PDF editing with text editing, page manipulation, annotations and form filling, per the vendor's documentation.
Format support (docx, xlsx, pptx, ODF)	Native support for ODF and Microsoft formats including .docx, .xlsx and .pptx. Test round-trip saves, since fidelity can vary by feature.	Native formats are .docx, .xlsx and .pptx, with conversion from formats such as DOC, ODT, RTF, ODS, CSV and ODP. Test round-trip fidelity.
Co-authoring	Supports multiple users editing one document. Load balancers must route by the WOPISrc parameter so co-authors reach the same pod. Test concurrent editing under your expected load.	Supports simultaneous editing. Connection limits differ by edition, so confirm the current limits for your edition and expected user count.
Platform integration (WOPI)	Integrates through WOPI with Nextcloud, ownCloud, Seafile, Alfresco, Mattermost and other platforms. Confirm your file platform version is supported.	Integrates with Nextcloud, ownCloud, Seafile and WOPI-compatible platforms. Confirm the connector version for your file platform.
Admin controls and support	Community (CODE) is not recommended for production. Paid editions add support, SLAs and signed security updates. Ask for the scope in writing.	Community support runs through GitHub and the forum, with configuration through config files. Enterprise adds an admin panel, white labeling and paid support tiers.

Collabora Online or ONLYOFFICE Docs: when each one fits

Both Collabora Online and ONLYOFFICE Docs edit Word, Excel and PowerPoint files in the browser and plug into Nextcloud and other file platforms. The choice depends on license terms, the support you need, how your users work with Office formats, and whether you embed the editors in a product you sell.

Collabora Online, paid edition for production

Collabora Online is built on LibreOffice technology, is licensed under MPL-2.0, and connects to file platforms through the WOPI protocol, with Nextcloud among the listed integrations. It fits organizations that want LibreOffice-based editing behind their own file platform and need production support. The paid edition adds long term support, an SLA, signed security updates and customer portal access. Confirm how your Office files render in practice, since LibreOffice-based editing and Microsoft's own apps can differ on complex layouts, macros and tracked changes. CODE is not recommended for production.

Collabora CODE for testing

CODE is the free Collabora Online Development Edition, released roughly once a month as a rolling release. Collabora describes it as suited to testing, home use or small teams and not recommended for production. It is useful for a proof of concept that tests your Nextcloud integration, document samples and Helm or Docker deployment before you budget for the paid edition. Plan the move to the paid edition before go-live, and confirm which updates and fixes you will receive once you leave CODE.

ONLYOFFICE Docs Community, AGPL-3.0

ONLYOFFICE Docs Community Edition is licensed under AGPL-3.0 and treats .docx, .xlsx and .pptx as native Office Open XML formats, with PDF editing that covers text, pages, annotations and form filling. Release 9.4 removed the 20 simultaneous connection limit from the Community Edition and merged it into a single process without RabbitMQ or database dependencies. Support comes through GitHub and the community forum, and configuration is done through config files, so check that your team can operate it without vendor support.

ONLYOFFICE Enterprise Edition

The Enterprise Edition adds an admin panel, white labeling, scaling for thousands of users and Basic, Plus or Premium support tiers, according to ONLYOFFICE's edition comparison. It fits organizations that need vendor support, administration through a panel rather than config files, or a branded editor. Ask ONLYOFFICE for the exact license terms, support response commitments and per-user or per-server pricing in writing, and confirm which features your scale requires before you assume the Community Edition is insufficient.

ONLYOFFICE Developer Edition for embedding

The Developer Edition uses a commercial license and is meant for software vendors that embed the editors in services they provide to customers. If your organization only uses the editors internally, this edition is usually not the relevant choice. If you are a vendor building a customer-facing product, review the AGPL-3.0 obligations of the Community Edition with counsel first, because they can require source disclosure for modified network services. Confirm the license scope in writing before committing.

How docx, xlsx and pptx fidelity is tested before cutover

Fidelity depends on what is inside the files, not on the file extension. A plain Word letter and a contract with tracked changes, nested numbering, form fields and custom styles are both .docx, but they fail in different ways. Before choosing between Collabora Online and ONLYOFFICE Docs, list the features your documents actually use: macros (which the browser editors do not run in the same way desktop Office does), tracked changes and comments, complex tables with merged cells, charts linked to embedded workbooks, embedded objects, licensed or unusual fonts, and corporate templates with headers, footers and theme colors. Each of these is a separate test case, and the risky ones are usually a small share of the library.

Build a test corpus from a sample of real files, then round-trip it. Pull a representative set from each department's shared folders, including the oldest and most heavily edited files, and tag each one by the features above. Open every file in the candidate editor inside your Nextcloud or other file platform, make a defined set of edits, save, and reopen it in the original Office application. For spreadsheets, compare formulas, named ranges, number formats and recalculated results against the original. For presentations, compare slide count, transitions, speaker notes and font substitution. Record the result for each file as pass, minor change or blocking defect, and keep the originals unchanged so the comparison can be repeated after each editor upgrade.

DeployOpen prepares the test harness and evidence, but you decide whether the results are acceptable. DeployOpen can help assemble the corpus, script the round-trip checks and document the outcomes as part of a fixed-scope engagement. DeployOpen does not certify document fidelity, and no third party certifies it either. Agree the acceptance criteria in writing before testing starts, including which differences your business owners will tolerate, who signs off for legal and records-sensitive documents, and what happens to files that fail. Confirm with each editor vendor which features are supported in the version you deploy, because support changes between releases.

Running browser editing next to Microsoft 365 or existing file stores

Some organizations keep Exchange Online and desktop Office for now and only want to take browser editing off the Microsoft stack. In this pattern, the editing server sits beside the existing tenant, and documents are opened from a file platform that the organization controls. Mail, calendar and the Outlook client stay where they are, so this pattern changes the least for users, but it also means that the editing layer must still reach the file store where documents live.

Identity stays in Entra ID: Confirm whether the editing front end can federate with Microsoft Entra ID through OpenID Connect or SAML, so users do not get a second password.
File source decides the work: Documents in OneDrive or SharePoint can only be edited in the browser if they are copied or synced into the self-hosted file platform, or reached through a connector you have validated.
Version history is a separate question: Confirm how the chosen file platform keeps prior versions and metadata after a copy, since a simple file copy may not carry them.
Licensing is per product: Check the license terms of the editor and the file platform separately from the Microsoft licenses you keep.
Cutover is optional: Because mail does not move, you can run this pattern for a pilot group before deciding on any later move.

Before you commit, ask the vendor or integrator to show a document round trip from the self-hosted editor to the storage source and back, including locking and conflict behavior.

Moving documents and editing workflows off Office for the web

This sequence moves Word, Excel and PowerPoint editing from Office for the web to browser editors you host, with each document type checked for fidelity before any user depends on it.

Inventory document types and editing habits
The document owner or records lead lists every file type in use, such as docx, xlsx, pptx, PDF and legacy formats, and identifies which SharePoint sites and OneDrive folders hold them. Include macros, embedded objects, tracked changes, comments, co-authoring habits and external links, because these drive fidelity testing. Confirm with business owners which workflows depend on Office for the web features, such as Excel Online data connections or PowerPoint co-authoring. The output is a register of document types, owners, volumes and must-keep features that you can hand to the editor selection team.
Select the browser editor and file platform
The platform team compares Collabora Online and ONLYOFFICE Docs against the register, focusing on docx, xlsx and pptx fidelity, PDF needs, integration with the chosen file platform such as Nextcloud, and the licensing of each edition. Collabora Online is MPL-2.0 licensed, with the free CODE edition not recommended for production, and ONLYOFFICE Docs Community Edition is AGPL-3.0 licensed, with its Enterprise Edition adding an admin panel and support tiers. Ask each vendor for written statements on support, security update delivery and any commercial terms that apply to your use. The output is a signed decision record naming the editor, the file platform and the edition.
Deploy the editor and file platform in a test environment
The platform engineering team installs the file platform and editor in a non-production environment inside your own infrastructure, with WOPI or connector configuration tested against a sample tenant. For Collabora on Kubernetes, check the Helm chart guidance: horizontal autoscaling is disabled, replicas are set manually, and the load balancer must route by the WOPISrc parameter so all users editing one document reach the same pod. Confirm ingress support for your controller. The output is a working test instance where a sample file opens, edits and saves through the browser.
Run the fidelity corpus against the test instance
The document owner and a security engineer open a representative set of files from the inventory, including the most complex documents, in the browser editor and compare layout, fonts, tables, charts, comments, tracked changes and macro behavior against the original Office for the web rendering. Record each defect, decide whether it is acceptable, and send blockers to the editor vendor or your integrator. Test save-back to the original format and round trips for docx, xlsx and pptx. The output is a signed fidelity report with pass, accepted and blocked categories.
Export source files with Purview eDiscovery
The Microsoft 365 compliance administrator creates an eDiscovery case in Microsoft Purview, searches the relevant SharePoint sites and OneDrive accounts, and exports the results as native documents with the version history you have selected. Exporting requires a Microsoft 365 E3 or E5 license, and search export packages expire 14 days after creation, so download and verify each package within that window. Keep a manifest that maps each exported file to its source location and owner. The output is a verified set of native files and a manifest, both stored in a restricted location for import.
Import, link and checksum documents
The migration engineer imports the exported files into the file platform, preserves folder structure and ownership, and reapplies sharing rules as agreed with document owners. Compare file counts and checksums against the manifest and investigate any mismatch. Update internal links that pointed to SharePoint or OneDrive so they resolve to the new location, and record exceptions. The output is an import report showing matched counts, checksum results and a list of links that need manual correction.
Pilot with a defined user group
A small group of users from the affected teams edits real documents in the new environment for an agreed period, using the fidelity corpus as a checklist. Collect defects, measure editing and save failures, and review co-authoring behavior with the editor's support channel. Confirm that backups run before pilot edits and that restores have been tested on the pilot data. The output is a pilot sign-off from the document owners listing any open issues that block cutover.
Cut over with backup and rollback
Before cutover, take a full backup of the file platform and its database, and freeze writes in the source for the affected sites. Redirect users to the new platform, keep the source read-only for an agreed fallback window, and keep the export packages and manifest until owners confirm the move. Define rollback triggers in advance, such as unrecoverable save failures on critical files, and test the restore path for the file platform before going live. Nextcloud requires upgrades one major version at a time with a backup before each upgrade, so record the version and backup identifier. The output is a cutover record with the backup reference, the rollback runbook and the date the source was made read-only.

What drives the cost of self-hosting web Office

The editor licence is the smallest line item in most self-hosted web Office budgets, and it is also the one people compare first. Collabora CODE and ONLYOFFICE Docs Community Edition are free to use under their open-source licences, but CODE is described by Collabora as not recommended for production, so a production deployment either uses the paid Collabora Online Business plan or relies on your own testing and patching of a community build. The Business plan is listed at 3 euros per user per month for up to 99 users and includes long term support, an SLA and signed security updates. Above 99 users, Collabora moves to a quoted Enterprise plan. ONLYOFFICE's admin panel, white labeling and Basic, Plus or Premium support sit in its Enterprise Edition, so confirm which of those you need before you choose the Community build. If you run Nextcloud as the front end, add Nextcloud Enterprise, which has a 100-user minimum and list prices by tier, and ask whether your user count justifies it.

Infrastructure and labour usually cost more than licences over the life of the system. The Collabora Helm chart recommends production limits of 8 CPU cores and 8000 MiB of memory per pod, with requests of 4 cores and 6000 MiB, and it disables horizontal autoscaling, so you size a fixed number of replicas and pay for them whether or not they are busy. Ask your integrator to state the replica count, the load balancer configuration that routes by the WOPISrc parameter, and the storage and database capacity behind Nextcloud. Deployment and integration labour is largely one-time: installing the editor, connecting it to Nextcloud over WOPI, configuring LDAP or SSO, and testing format fidelity on your real .docx, .xlsx and .pptx files. Recurring costs include monitoring, backups, security patching, and the Nextcloud major upgrades, which must be applied one version at a time with a backup before each step.

When you request a written quote, ask for each cost separately: licence or subscription by year, infrastructure sizing for production and test environments, one-time integration and testing, the upgrade and patch service after go-live, and support hours with response times. Confirm who owns the Kubernetes cluster, the storage and the backups, and whether the quote assumes the paid Collabora tier. Fixed-scope engagements from DeployOpen are agreed in writing before work starts, so the scope document should name the user count, the document volume to migrate, and the test cases for format fidelity. Ongoing support and upgrades are available as retainers, which makes them easier to compare with a fixed licence fee than with a one-off project estimate.

Questions buyers ask before replacing Office for the web

How much effort does replacing Office for the web take?

The effort depends mainly on how many users, document types and integrations are in scope, not on the editor alone. Effort rises with the number of file platforms that need the editor connected, the volume of macros, embedded objects and custom templates that must render correctly, the authentication design (LDAP, Active Directory, OpenID Connect or SAML), and the load profile for concurrent editing. Collabora Online and ONLYOFFICE Docs both connect to Nextcloud through the documented office integration, so the file platform work is often smaller than the fidelity work. Ask any provider for a written scope that lists each workload, each document family and each integration, because those items determine the cost of the engagement.

Can our team deploy Collabora or ONLYOFFICE without outside help?

A team with container and reverse proxy experience can deploy either editor, but production readiness takes more than a working demo. Collabora Online documents Docker images, system packages and Kubernetes deployment, and its Helm chart README states that horizontal pod autoscaling is disabled because scaling breaks collaborative editing, so replicas are set by hand and the load balancer must route by the WOPISrc parameter. ONLYOFFICE Docs recommends Docker. Teams without this experience usually need help with ingress, TLS, load balancing, backup and upgrade routines. Confirm your in-house skills against those tasks before deciding what to hand over.

How long does a pilot run, and what does it need from our side?

A pilot's length depends on how many document families you test and how many real users participate, not on a fixed period. A useful pilot needs a representative sample of your Word, Excel and PowerPoint files, a named group of users who work in those files daily, a test instance of your file platform, and someone who can record rendering differences and decide which ones matter. Plan for the pilot to include concurrent editing sessions, not only single-user viewing. Any timeline should come from a written scope agreed before work starts, and your provider should state what it needs from your team, including access, sample data and approval steps.

Do Collabora or ONLYOFFICE match our Word, Excel and PowerPoint files?

Both editors handle the Office Open XML formats, but fidelity varies by document, so you should test your own files. ONLYOFFICE's DocumentServer README names .docx, .xlsx and .pptx as its native formats and lists conversion for formats such as DOC, ODT, RTF, ODS, CSV and ODP. Collabora Online states that it edits ODF and Microsoft formats including .docx, .xlsx and .pptx. Focus your tests on tracked changes, comments, complex tables, charts, embedded objects, custom fonts, macros, slide transitions and Excel formulas with external references. Record each difference with a severity, and decide in advance which differences are acceptable for each team.

Which license applies to each edition of Collabora and ONLYOFFICE?

Collabora Online's server code is licensed under the Mozilla Public License 2.0, and its free CODE edition is described by Collabora as suited to testing, home use or small teams and not recommended for production. Collabora's paid Business plan, listed at 3 euros per user per month for up to 99 users, includes long term support, a service level agreement, signed security updates and customer portal access. ONLYOFFICE Docs Community Edition is licensed under AGPL-3.0, while its Enterprise Edition adds an admin panel, white labeling, and Basic, Plus or Premium support. A Developer Edition under a commercial license applies to software vendors that embed the editors in services for customers. Have counsel confirm which terms apply to your deployment model.

How do updates and upgrades work for a self-hosted editor?

You own the update schedule, so plan a routine for the editor and for the file platform it connects to. Collabora's free CODE edition is a rolling release that Collabora releases on average once a month, while its paid edition supplies tested updates and security fixes; the 25.04 branch was still receiving point releases in 2026. ONLYOFFICE publishes DocumentServer releases on GitHub, and its Docs 9.4 release consolidated the Community Edition into a single process. On the Nextcloud side, you cannot skip major releases, so each upgrade moves one major version at a time, with a backup before each step and third-party apps disabled until they are confirmed compatible. Ask any provider for a written upgrade and rollback procedure.

Can DeployOpen run the fidelity testing for our Office files?

Yes, DeployOpen can plan and run fidelity testing as part of a fixed-scope engagement, with the document families, user groups and pass criteria agreed in writing before work starts. The testing would cover how Collabora Online and ONLYOFFICE Docs open, edit and save your Word, Excel and PowerPoint files inside your chosen file platform, and results would be documented for your decision. DeployOpen does not issue audit reports or certifications, and fidelity results are an engineering input for your own sign-off rather than a guarantee. Ask for the test matrix, the reporting format and the retest process in the written scope.

How DeployOpen works on this

DeployOpen plans, implements, customizes, integrates, hardens, backs up and documents self-hosted open-source platforms inside your own cloud accounts, data centers or air-gapped networks. For web office replacement, that means agreeing the document editing service, the file platform it attaches to and the format testing before any build starts.

How we scope

Engagements are fixed-scope, with the office editing service, file platform and user groups agreed in writing before work starts.
The written scope lists which Word, Excel and PowerPoint formats must round-trip, and which legacy macros or templates are out of scope.
Deployment hosting, network placement and whether the editors run inside Nextcloud or another file platform are decided during scoping.

How we build

Collabora Online or ONLYOFFICE Docs is installed in your environment and connected to the file platform through the WOPI integration.
Sample documents from your own file shares are tested for docx, xlsx and pptx fidelity, including tables, fonts, charts and comments.
Hardening covers TLS, access controls, authentication through your directory and malware scanning of uploaded files.

How we hand over

Deliverables include configuration records, architecture diagrams, runbooks for scaling and upgrades, and the test results agreed in scope.
Backup and restore procedures for the file platform and its database are documented and exercised before handover.
Your team receives documentation for the edition and license terms that apply, so ownership of the stack stays with you.

How we support

Ongoing support, upgrades and continuous testing are available as retainers, scoped separately from the build.
Upgrades of the file platform and editing service are planned one major version at a time, with a backup before each step.
Quotes follow from the written scope, so ask for the components, edition support terms and recurring operations effort included.

Open-source alternative to Office for the web