#1★ TOP PICK
Zammad
A full-featured, AGPL-licensed help desk with ticketing, a knowledge base, and multi-channel inboxes.
90
OPEN SOURCEAGPL-3.0SELF-HOSTLOCAL-FIRST
Zammad is a mature, actively-developed open-source help desk covering email, chat, and social ticketing, SLAs, a customer-facing knowledge base, and text modules/macros — the closest like-for-like replacement for Zendesk's core ticketing product. It's built in Ruby on Rails with an Elasticsearch-backed search index and ships an official Docker Compose stack, so a self-hosted install is a well-trodden path rather than a science project.
Strengths
- +Full AGPL-3.0 open-source core — no enterprise-only feature split
- +No per-agent limit when self-hosted; unlimited tickets and mailboxes
- +Mature product: multi-channel (email, chat, Twitter/Facebook, telephony via CTI), SLAs, and a real knowledge base out of the box
- +Official Docker Compose and package installers make self-hosting straightforward
Trade-offs
- −Elasticsearch is a required dependency for full-text search, adding real memory/operational overhead versus a lighter stack
- −UI and feature depth are solid but noticeably less AI-forward than current Zendesk (no built-in generative AI agent as of this writing)
- −Smaller third-party app marketplace than Zendesk's 1,800+ integrations
Free to self-host with unlimited agents; optional managed cloud plans start around €19/agent/month and Zammad also sells paid support contracts for self-hosted installs. #2
FreeScout
A lightweight, completely free, self-hosted shared mailbox modeled on Help Scout's simplicity.
86
OPEN SOURCEAGPL-3.0SELF-HOSTLOCAL-FIRST
FreeScout is a PHP/Laravel help desk built as a shared-inbox clone of Help Scout: email comes in, becomes a conversation, and agents reply, tag, assign, and add private notes from one lightweight interface. The core is entirely free with no agent or ticket limits; the project sustains itself by selling small optional modules (knowledge base, reports, custom fields, CRM — $4-$15 one-time each) rather than a subscription, so the base product never expires or gates users.
Strengths
- +AGPL-3.0, fully open source, verified against the project's own repo license
- +No recurring cost at all for the core product — pay once (if ever) for optional modules, never a subscription
- +Very lightweight: runs comfortably on a small VPS or shared PHP hosting, minimal moving parts
- +Familiar Help Scout-style shared-mailbox workflow with a low learning curve
Trade-offs
- −Native channel coverage is email-first; live chat, WhatsApp, and social messaging require third-party modules or aren't available
- −Reporting and analytics are functional but noticeably thinner than Zendesk's built-in dashboards
- −Smaller contributor base than Zammad or Chatwoot; some advanced features only ship as paid modules
Core is free forever, unlimited agents and mailboxes. Optional one-time modules (not subscriptions) cost $4-$15 each for extras like knowledge base, reports, or CRM fields. #3
Chatwoot
An open-core omnichannel inbox strongest at live chat, WhatsApp, and social messaging.
84
OPEN SOURCEMIT (core); enterprise/ directory is a separate proprietary license, verified directly against chatwoot/chatwoot's own LICENSE fileSELF-HOSTLOCAL-FIRST
Chatwoot unifies live chat, WhatsApp, Instagram, Facebook, Telegram, SMS, and email into one team inbox, with a Captain AI layer for FAQ-driven auto-replies on paid tiers. Chatwoot ships as an 'open core' project: the community edition (the whole visible codebase outside one folder) is MIT-licensed and free to self-host with no seat limit, while a smaller set of enterprise features (SSO/SAML, agent capacity management, custom branding, SLA policies) live in a separate 'enterprise/' directory under Chatwoot's own proprietary license and require a paid subscription even when self-hosted.
Strengths
- +MIT-licensed core is genuinely open source, not source-available — you can audit, fork, and modify it freely
- +Best-in-class channel coverage for chat-first support: WhatsApp, Instagram DM, Telegram, SMS, and live chat widget out of the box
- +Very active project (multiple releases a month) with a large community and strong docs
- +Self-hosting the community edition is completely free with no agent-count restriction
Trade-offs
- −SSO/SAML, SLA policies, and agent capacity management sit behind a paid license even when self-hosted — not a full feature set for free
- −Captain AI (the auto-resolution layer) is a paid add-on, not part of the free community edition
- −Less oriented toward classic long-form ticket workflows than Zendesk or Zammad; strongest for chat-style support
Community edition free to self-host, unlimited agents. Self-hosted paid tiers: Premium Support $19/agent/month (Captain AI, voice, branding, roles/permissions) and Enterprise $99/agent/month (adds SSO/SAML, SLA). Cloud-hosted plans start at $19/agent/month (Startups tier). #4
UVdesk
A Symfony-based open-source help desk with ticketing, a knowledge base, and e-commerce integrations.
79
OPEN SOURCEOSL-3.0SELF-HOSTLOCAL-FIRST
UVdesk is a PHP/Symfony help desk offering email ticketing, a customer knowledge base, saved replies, workflows, and native integrations aimed at online sellers (Shopify, WooCommerce, Magento). It's a solid, mature option for teams already in the PHP/Symfony ecosystem or running an e-commerce storefront who want ticketing tied closely to order/customer data.
Strengths
- +Open Software License 3.0 is OSI-approved, and the code is fully visible/modifiable
- +Strong out-of-the-box e-commerce integrations (Shopify, WooCommerce, Magento) that neither Zammad nor FreeScout match natively
- +Sizeable community (19k+ GitHub stars) and an active Symfony-based plugin ecosystem
- +Free self-hosted core with no agent-count ceiling
Trade-offs
- −OSL-3.0 is a copyleft license with unusual patent-termination clauses that are less common and less well-understood than AGPL/MIT/Apache — worth a quick read for anyone building a commercial product on top of it
- −Release cadence is slower than Zammad or Chatwoot (last tagged activity noticeably quieter over the past several months)
- −Symfony/PHP setup has a steeper install curve than FreeScout's simpler stack
Free to self-host (community edition). UVdesk also sells a separate hosted SaaS plan and paid marketplace add-ons.