Open-source alternatives to Glean

Which open-source alternative to Glean fits your situation

If your main need is search across company connectors, Onyx is the closest self-hosted match to Glean, because it indexes content from many sources and can run in an air-gappable configuration. If your main need is a chat interface first, with documents as one input, Open WebUI, LibreChat and AnythingLLM fit better. The reader's situation usually decides which way to go: a renewal under review, a residency or air-gap requirement, or concern about lock-in all point toward a self-hosted option, but the search or chat emphasis determines the tool. Teams start looking at alternatives for a specific reason. Under both Glean Hosted and Customer Hosted deployments, Glean remains responsible for infrastructure and application management, including upgrades, patching and monitoring. The Customer Hosted model does run in your own GCP or AWS account, so data placement is different from Glean Hosted, but the operating responsibility sits with the vendor in both cases. If your organization wants to control upgrade timing, patch windows and monitoring data, or needs the stack inside a network with no outbound access, a self-hosted platform moves those decisions to your team or your implementation partner.

Before you shortlist Onyx, confirm three things with the vendor and in your own environment: which connectors your sources require, whether your identity provider works with its Google OAuth, OIDC or SAML options and SCIM provisioning, and how permissions from each source carry into search results. Then decide who will operate the stack after go-live, since self-hosting shifts upgrades, backups and monitoring to your side. Ask your Glean account team for the exact contract terms on deployment responsibilities so you can compare them line by line against the self-hosted operating tasks.

Four open-source options and when each fits

Glean's search depth comes from its connectors and permission model, so the open-source options differ mainly in how much of that they cover. Onyx is the only one here built around enterprise search across company systems, while the other three are chat interfaces that differ in document handling, authentication and licensing.

Onyx for permission-aware search

Onyx is the closest functional match to Glean's search: it indexes more than 50 applications and carries their permissions into answers. Its Community Edition is MIT licensed and covers RAG, chat, agents and actions, while code in the ee directories falls under the Onyx Enterprise License. Check which enterprise features your requirements need before you assume the Community Edition covers them. Confirm connector coverage for your specific SaaS and on-premises sources.

Onyx for air-gapped deployments

Onyx documents a self-contained deployment where the document index, database and processing run inside your environment. It deploys with Docker, Kubernetes, Helm or Terraform and can use self-hosted models through Ollama, LiteLLM or vLLM. Your team operates this stack, so plan for patching, index maintenance and capacity planning. Ask DeployOpen or your internal platform team to confirm which components need outbound network access before you declare the environment air-gapped.

Open WebUI for offline chat

Open WebUI is a self-hosted AI interface that can run fully offline and works with Ollama and OpenAI-compatible APIs. It is a strong choice for chat over local models, but it is less of a company-wide search layer than Onyx. Its license is BSD-3-Clause in style, with an added clause that restricts removing or altering Open WebUI branding unless a deployment has 50 or fewer users in a rolling 30-day period, or you hold permission or an enterprise license. Legal review should happen before rollout.

LibreChat for multi-provider teams

LibreChat is MIT licensed and self-hosted with Docker, supporting OpenAI, Azure OpenAI, Google, Vertex AI, Anthropic, AWS Bedrock and Ollama. It includes an agent framework with Model Context Protocol support and multi-user sign-in through OAuth2, LDAP and email. It fits teams that need to connect several model providers and internal tools, but document search across company repositories is not its core function. Confirm how identity mapping and group policies work with your directory before go-live.

AnythingLLM for document workspaces

AnythingLLM from Mintplex Labs is MIT licensed and runs as a Docker deployment or desktop app on macOS, Windows and Linux. It supports multiple users and connects local or cloud models to documents you ingest, with built-in agents and vector databases. It suits focused document question-answering for a team or department. Because it is file-driven rather than connector-driven, confirm how it keeps source permissions current if your content lives in shared drives and collaboration tools.

How Glean capabilities map to open-source coverage

This table compares the main Glean capabilities with what Onyx covers in a self-hosted deployment, and where the reader must confirm details before deciding. Read each row as a question to check against your own sources, identity provider and compliance scope. The main takeaway is that Onyx covers connectors and search well on paper, but permission depth, audit detail and upgrade operations need verification before you commit.

Glean capability	Onyx open-source coverage	What to confirm before deciding
Connectors to company content	Repository includes connectors for SharePoint, OneDrive, Outlook, Teams, Google Drive, Gmail, Confluence, Jira, Slack and Salesforce	Confirm connector parity and sync depth for each source you use, including attachments, chat history and custom fields
Permission-aware results	Onyx indexes applications with their permissions, so answers can respect source access rules	Confirm which permission sync features sit in the Onyx Enterprise License versus Community Edition, and test with real user groups
SSO and user provisioning	Supports Google OAuth, OIDC or SAML single sign-on and SCIM provisioning	Confirm SCIM behavior with your identity provider and how group changes propagate to permissions
Model choice	Works with self-hosted models through Ollama, LiteLLM or vLLM, and with hosted model providers through configuration	Confirm which model providers and inference locations meet your data residency rules
Deployment options	Self-contained services deployable with Docker, Kubernetes, Helm or Terraform, and documented as air-gappable	Confirm the topology your security team will accept, including where the document index and processing run
Audit and admin controls	Admin functions exist, but the depth of audit logging and usage analytics is not established here	Ask for the audit event list, export format and retention, and compare them with your compliance evidence needs
Upgrades, patching and monitoring	Glean operates these in its Hosted and Customer Hosted models; with Onyx your team or a services partner operates them	Budget for staff or retainer time to run upgrades, security patches, backups and monitoring in your own environment

How Onyx keeps search results permission-aware

Onyx's permission-aware search depends on indexing each document together with the access rules of the source application, so a user should only see results they could already open in SharePoint, Google Drive, Confluence or Slack. The Onyx README states that it indexes 50+ applications with their permissions, and the connectors directory in the repository shows which sources are covered. The practical question for a Glean comparison is not whether the feature exists but how faithfully it mirrors your tenant: which permission model each connector reads, how often it refreshes, and what happens when access changes between sync runs.

Four behaviors need explicit testing in a pilot against your own tenant rather than an assumption of parity with Glean. First, sync latency after permission changes: remove a user from a site or folder, then confirm how long a search still returns the document. Second, deleted or deactivated users: check whether their access disappears from the index and whether their historical content stays searchable by others. Third, nested groups: test a document shared to a group that contains another group, and a member added through the nested group only. Fourth, shared drives and externally shared items: confirm that drive-level and link-based permissions are mapped the way your administrators expect.

Ask DeployOpen or your own platform team to document the permission sync interval for each connector, the identity provider and SCIM settings used for user lifecycle, and the test cases with expected and observed results. Run the same queries as a pilot user before and after each permission change, and keep the evidence for your access control reviews. Glean's Customer Hosted model also handles connector operations, so compare who owns the sync schedule, failure alerts and remediation, because that operational responsibility is part of the permission guarantee.

What drives the cost of replacing Glean

This table separates what you pay Glean from what you would pay to run Onyx in your own cloud account or data center, and marks each component as one-time or recurring. Use it to see which costs move with connector count, user count, document volume and model choice, and what to request in a quote. No prices are shown because none are supplied for these components, so ask each party for written figures.

Cost component	Who is paid or who carries it	One-time or recurring	What drives it up or down
Glean subscription (Hosted or Customer Hosted)	Glean, under its contract terms	Recurring	Contracted seats, connectors and deployment model. Ask Glean whether Customer Hosted changes the fee structure.
Cloud or data center infrastructure	Your cloud provider or data center vendor	Recurring	Index size, replica count, storage and compute sizing. Customer Hosted runs in your own GCP or AWS account, so you carry this cost.
Implementation and deployment	DeployOpen or your internal platform team	One-time	Target architecture, air-gap requirements, SSO and SCIM setup, and number of environments. Request a fixed-scope written plan.
Connector configuration and permission mapping	DeployOpen or your internal platform team	One-time, with ongoing changes	Number of sources such as SharePoint, Confluence, Jira and Slack, plus how permissions are mirrored. Each new source adds setup and testing.
Migration and parallel run	Your internal teams and the implementation partner	One-time	Length of overlap with Glean, user groups moved and search quality testing. Ask for the parallel-run exit criteria in the scope.
Model inference	Hosted API provider or your GPU provider	Recurring, usage-based or fixed	Query volume, model choice and context size. Self-hosted models through Ollama, LiteLLM or vLLM shift cost to GPUs you run.
Upgrades, patching and monitoring	Your platform team, or a retainer partner	Recurring	Release cadence, number of environments and how often connectors need updates. Glean currently handles this under Customer Hosted, so this cost moves to you.
On-call and staff time	Your internal staff	Recurring	Hours of coverage, incident frequency and the number of people trained on the stack. This is often the least visible cost.
Support retainer	DeployOpen or another support provider	Recurring, optional	Response expectations, upgrade scope and continuous testing included. Ask for the retainer terms in writing before signing.
Enterprise license for Onyx	Onyx, for code under the Enterprise License	Recurring, if you need ee features	Which ee features you require, such as certain enterprise capabilities. Confirm the Community Edition covers your needs before budgeting.

What you give up and the usual workarounds

Moving from Glean's hosted or customer-hosted model to Onyx trades vendor-run operations and a polished catalog for control over where data and models live. Each card below names one trade-off, what it costs in practice, and the workaround most teams use to close it.

Vendor-managed upgrades move to your team

In both Glean deployment models, Glean remains responsible for infrastructure and application management, including upgrades, patching and monitoring. With Onyx, your team or a partner owns those duties, including tracking security patches for every container and database, testing upgrades against your connectors, and watching health and index freshness. Ask for a written runbook and an upgrade cadence before you commit. A managed operations agreement or support retainer can take this work back out of your queue.

Narrower connector catalog

Glean's pre-built connector breadth and product polish are the reasons many buyers choose it. Onyx's public connectors directory covers sources such as SharePoint, OneDrive, Outlook, Teams, Google Drive, Gmail, Confluence, Jira, Slack and Salesforce, but you should map every source your staff actually uses against that list. Gaps are usually filled with a custom connector, which carries build, test and maintenance effort that recurs as source APIs change.

Enterprise features behind a license

Onyx Community Edition is MIT licensed, but code in the ee directories falls under the Onyx Enterprise License. Features that sit there may be needed for your SSO, SCIM provisioning or permission handling, so confirm which ones you require before design starts. Ask Onyx for written terms covering the features you need, the number of users, and support. Budget for the license as a recurring cost alongside infrastructure.

Open WebUI branding restrictions

If you deploy Open WebUI as the chat front end, its license forbids removing or altering the Open WebUI branding unless the deployment has 50 or fewer users in a rolling 30-day period, the copyright holder grants permission, or an enterprise license is bought. Larger rollouts that want a white-labeled interface need one of those three options. Have legal review the current license text and the history file, since code before a specific commit remains under the earlier BSD-3-Clause terms.

Model hosting and capacity ownership

Glean's hosted and customer-hosted models do not leave you to size inference, but Onyx works with self-hosted models through Ollama, LiteLLM or vLLM, or with external model APIs. Choosing a self-hosted model means you pay for GPU or CPU capacity, its availability, model upgrades and evaluation of answer quality. Ask for a sizing estimate tied to your query volume and document count, and confirm whether an API model is acceptable under your data rules.

Operational skills and on-call coverage

Running the search index, database, connectors and model endpoints means someone must answer pages when a sync stalls or a permission update fails. Permission-aware answers depend on connectors keeping access data current, so a silent sync failure can expose stale access rights. Confirm who holds on-call duty, what the escalation path is, and how you will test that revoked permissions disappear from results. Continuous testing and security reviews can be added through a retainer.

How moving off Glean is sequenced

The sequence turns an undocumented search estate into a tested, permission-aware Onyx deployment that replaces Glean one source and one group at a time. Each step ends with evidence that the next step can rely on, and the Glean tenant is retired only after that evidence is archived.

Inventory connectors, users, groups and permissions
Export the list of Glean connectors, the sources each one indexes, the users and groups that can search them, and the permission model each source enforces, such as SharePoint site groups or Google Drive sharing. Ask Glean and your identity team to confirm which connectors are active and which are only configured. Your security team and the content owners of each source review the inventory. The output is a signed inventory that lists every source, its owners, its sensitivity classification and the group that should see its content.
Map connector scopes and SSO settings
For each source, record the OAuth scopes or service account permissions Glean uses, then identify the equivalent Onyx connector and the minimum scopes it needs. Document how identity flows today, including the identity provider, SAML or OIDC settings, and any SCIM provisioning, and map those to the Onyx options for Google OAuth, OIDC or SAML and SCIM. Confirm with Onyx and with each source vendor whether a given connector supports the permission sync you need. Identity and platform engineering sign off on the mapping. The output is a gap register listing any source or permission behavior that Onyx does not match yet.
Build the Onyx environment in your infrastructure
Deploy Onyx into your own cloud account, data center or air-gapped network using the Docker, Kubernetes, Helm or Terraform method your platform team has approved. Connect the model endpoint you chose, which can be a self-hosted model served through Ollama, LiteLLM or vLLM, or an approved external API. Configure logging, backup and access controls before any company data is ingested. The output is a reviewed environment baseline with documented configuration, the model in use and the identity integration tested with a small set of test accounts.
Run a pilot on a limited source set
Choose a small set of sources with clear owners and low sensitivity, then index them in Onyx with the permission mapping from the earlier steps. Ask a limited group of pilot users to run their normal searches in both tools and record where results differ. Test that a user who lacks access in the source system receives no content from Onyx, using accounts across at least two groups. The output is a pilot report listing results, permission test outcomes and any defects that must be fixed before wider use.
Run both tools against the same test queries
Write a fixed set of test queries with known expected answers and known restricted documents, and run them through Glean and Onyx under the same user accounts. Compare the cited sources, the answer accuracy and the permission outcomes, and have business owners score the results. Repeat the run after each connector change so that regressions are visible. The output is a parallel-run record that shows, by source and group, where Onyx matches Glean, where it falls short and what has been accepted as a known difference.
Cut over by source and group
Move one source at a time, starting with the sources and groups that passed the parallel run. For each cutover, disable the Glean connector for that source after Onyx has completed a full index and the permission tests pass, and tell users which tool to use. Keep a documented rollback path for each cutover until the owners confirm it is stable. The output is a cutover log that records the date, source, group, approver and rollback status for every change.
Decommission the Glean tenant and retain evidence
After every source is cut over, revoke Glean connector credentials and service accounts, remove the data it holds under your agreement with Glean, and confirm the deletion in writing with Glean. Confirm with your legal and records team which logs, inventories, test results and cutover records must be kept for audit, and export them to your own retention store. Ask your contract owner to confirm the end of service terms and any data return or deletion obligations. The output is a decommissioning record with the deletion confirmation and an archive index that an auditor can read without access to the Glean tenant.

Which option fits by situation

When the main requirement is that content and processing stay inside your own network, Onyx is the option in this set that documents an air-gappable, self-hosted deployment. The document index, database and processing run within a self-contained set of services, deployable with Docker, Kubernetes, Helm or Terraform. Glean's Customer Hosted model also keeps the stack in your cloud account, but Glean remains responsible for infrastructure and application management, so the operating model differs from a fully self-operated stack.

Deployment target: Confirm whether you need a connected or fully disconnected network, since air-gapped installs change how updates and model artifacts reach the cluster.
Model location: Pair Onyx with self-hosted models through Ollama, LiteLLM or vLLM so that inference does not leave the network.
Update path: Plan how upgrades and container images are transferred into the isolated environment.
Operations ownership: Decide whether your platform team or a partner will patch, monitor and back up the stack.
Edition scope: Check which features sit under the Onyx Enterprise License in the ee directories before you rely on them.

Confirm with the Onyx project which features your air-gapped design requires and how they are packaged.

Questions buyers ask before replacing Glean

How much effort does replacing Glean with Onyx take, and what drives it?

The effort depends mostly on how many sources you index, how complex your permission model is, and how much of the answer quality work you take on. Each connector needs its credentials, scopes and sync schedule set up and tested, and SharePoint, Google Drive and Confluence usually carry the most permission logic. Model choice matters too: running Ollama, LiteLLM or vLLM in your own environment adds GPU capacity planning, while a hosted model API adds a data-processing review. Ask any partner for a written scope that lists sources, identity integration, model hosting and acceptance tests, because that list is what moves the quote. Onyx's own code is open source, so the license fee is zero, but the one-time build and the recurring operations work are the real costs.

Can our own team run Onyx without an outside partner?

Yes, if you already operate containers or Kubernetes, manage an identity provider and have someone who owns search quality. Onyx supports Docker, Kubernetes, Helm and Terraform, so the deployment tooling is familiar to most platform teams. The harder part is ongoing operations: upgrades, connector maintenance when a source API changes, index health, backups and monitoring. Glean's Customer Hosted model leaves those duties with Glean, so moving to Onyx moves them to you. Before deciding, count how many people would own the stack, how often you can absorb an upgrade, and whether you need a retainer for support and continuous testing. Some organizations keep the build in house and buy a fixed-scope hardening review.

What does the work need from identity, cloud and security teams?

Identity staff set up single sign-on and provisioning. Onyx supports SSO through Google OAuth, OIDC or SAML and SCIM provisioning, so confirm which of these your identity provider exposes and who maintains the group mappings. Cloud staff provide the hosting account, network segmentation, secrets storage and any GPU capacity for self-hosted models. Security staff review connector scopes, which should be read-only where possible, and decide how the index is encrypted, who can query it and how audit logs are kept. Each team should sign off on its part before connectors are pointed at production data. Ask your partner to name the owner of each control in the scope document.

How long should a pilot run before we commit?

No fixed duration applies to every organization, so confirm the length with your implementation partner and your own stakeholders before work starts. A useful pilot is long enough to index the sources you care about, run your real questions and compare results against a control group of known answers. Set exit criteria in advance: which sources must be indexed, which permission tests must pass, which users must find answers they currently get from Glean, and what operational runbook must exist. Keep the pilot on a scope you can later expand, so the work carries forward. Check with Onyx's documentation and your partner how long initial indexing takes for your data volume, since that figure varies widely by source.

Can we test whether permissions match Glean before cutover?

Yes, and you should test it before any user relies on the system. Pick a representative set of documents and users, then record what each user can see in Glean and in the replacement, including folders inherited from groups, shared links and recently changed access. Permission-aware search depends on the connector reading the source's access control lists correctly and on sync running often enough that revoked access disappears quickly. Include negative tests: a departing employee, a contractor with narrow access and a user in a restricted group. Document the results as evidence for your security and compliance reviewers. DeployOpen can plan and run this as a fixed-scope security test if you want an independent check.

What happens to our Glean contract and the data already indexed?

Your Glean contract terms govern notice periods, data return and deletion, so read them with your procurement and legal teams before giving notice. Ask Glean in writing what happens to indexed content, logs and embeddings at termination, and whether you can export them. On the replacement side, the indexes and logs live in your own infrastructure, so you control retention and deletion directly. Plan a parallel run so users keep a working search tool during cutover, and decide in advance how long the old system stays readable for audit purposes. Your records obligations, not the tool, usually set the retention period.

How DeployOpen scopes, migrates and supports the replacement

DeployOpen plans, implements, customizes, integrates, hardens, backs up, upgrades, documents and supports self-hosted open-source platforms inside the client's own cloud accounts, data centers or air-gapped networks. For a Glean replacement, that means agreeing in writing what Onyx or another platform will index, who it will answer for, and how the stack will be operated after go-live.

How we scope

Inventory which content sources, such as SharePoint, Confluence, Jira or Slack, must be connected and which must stay out of the index.
Document how source permissions must carry into search results, and where identity sync via Google OAuth, OIDC, SAML or SCIM is required.
Agree in writing on model hosting choices, data residency boundaries and who operates the stack, then issue a fixed-scope proposal with deliverables and timelines.

How we build

Deploy the chosen platform with Docker, Kubernetes, Helm or Terraform inside the client's infrastructure, including air-gapped networks where that is the requirement.
Configure connectors and test permission-aware answers against sample users from each group, so access behavior is verified before users see results.
Run security testing of the application, its APIs and its connectors, and record findings and fixes in a documented change log.

How we hand over

Deliver runbooks for deployment, connector onboarding, index rebuilds, backup and restore, and upgrades, written for your platform team.
Walk through admin operations with your staff and confirm who holds each responsibility after handover, including model keys and license obligations.
Provide compliance-readiness evidence such as configuration records and access reviews, noting that independent auditors and certification bodies issue any formal assessment.

How we support

Ongoing support, upgrades and continuous testing are available as retainers, scoped separately from the initial fixed-scope work.
Plan upgrades to Onyx releases and connector changes, reviewing license terms for the Community and Enterprise editions before each change.
Ask any provider, including DeployOpen, to confirm in the quote which operational tasks are included, how incidents are escalated and what is excluded.