Photo by Brett Sayles via PexelsQuick summary:
- Three open source ITSM tools structure the market in 2026: GLPI (integrated service desk and IT asset management), iTop (CMDB-focused, published by French vendor Combodo) and Zammad (multichannel ticketing, published in Germany).
- All three are free in their self-hosted edition, with no technician limit for GLPI and iTop, while ServiceNow remains proprietary software sold only on a quote basis, exclusively as SaaS.
- GLPI stands out for natively integrating IT asset management with the service desk, a scope ServiceNow only covers through add-on modules.
- The criterion that separates these tools the most is not the license but the actual feature scope: asset management for GLPI, CMDB for iTop, multichannel support for Zammad.
Comparison of open source ITSM software against ServiceNow
The table below compares four ITSM solutions on the criteria that matter most in a software decision: license model, vendor, hosting options, actual feature scope and pricing.
| Criterion | GLPI | ServiceNow | iTop | Zammad |
|---|---|---|---|---|
| Model | Open source (GPL) | Proprietary | Open source (AGPL) | Open source (GPL v3) |
| Vendor | Teclib (France) | ServiceNow Inc. (United States, listed on NYSE under ticker NOW) | Combodo (France) | Zammad GmbH (Germany) |
| Hosting | Free self-hosted, or paid Cloud/On-Premise (GLPI Network) | SaaS only | Self-hosted, or through integrator partners | Self-hosted, or vendor-hosted Cloud |
| Feature scope | ITSM and IT asset management (ITAM) natively integrated | Extended ITSM (ITOM, ITBM, multiple business workflows) | ITSM centered on CMDB and configuration management | Multichannel service desk and ticketing (email, chat, phone) |
| Primary target | SMB to large enterprise, public sector | Large enterprises and complex organizations | SMB to mid-market, public sector | SMB, customer and IT support teams |
| Pricing | Free self-hosted, quote-based subscription for Cloud and support | Quote-based, not published | Free self-hosted, quote-based support and hosting | Free self-hosted (Community edition), tiered Cloud subscription |
| Verdict | Most complete option on the ITSM plus asset management combination | Market reference for complex organizations, higher cost | Solid option if CMDB is the priority | Relevant choice for simple multichannel support |
Why compare ITSM tools on license and hosting, not just features
On core ITIL processes (incident, request and change management), functional gaps between the main ITSM platforms are limited. What really differentiates an open source ITSM tool from ServiceNow is the license (the right to modify and redistribute the code), the hosting mode (self-hosting possible or SaaS imposed) and the pricing model (free with optional support, or mandatory subscription). A selection method close to the one used for choosing an ERP for SME: scoping the actual feature requirements before comparing pricing sheets.
GLPI, the most complete open source ITSM software on service desk and asset management
GLPI is an open source ITSM software created in 2003, distributed under the GPL license and now published by French company Teclib. What sets it apart from most alternatives to ServiceNow, including other open source ones, is that it natively integrates service management (service desk, ITIL-aligned ticketing) and IT asset management (inventory, CMDB, equipment lifecycle) into a single tool.
Key characteristics
- Free software license: GLPI’s source code is public, modifiable and redistributable under GPL, with no license cost for the self-hosted edition
- Integrated asset management: inventory of workstations, servers and network equipment is native, with no third-party module required
- Two deployment modes: a free self-hosted edition with no technician limit, and a commercial GLPI Network offer (turnkey cloud or support on an existing installation) for organizations that want to delegate hosting and access tier-3 vendor support
Detailed comparison: GLPI, ServiceNow, iTop and Zammad
The most structural gap between GLPI and ServiceNow lies in the distribution model: ServiceNow offers no self-hosting option, its Now Platform running exclusively as SaaS, with pricing communicated only on request. GLPI, iTop and Zammad, by contrast, all share a free self-hostable edition, which shifts the cost question toward hosting and operations rather than the license itself.
Among the three open source ITSM tools, the gap lies in the actual feature scope rather than the license. iTop, developed by French vendor Combodo, emphasizes CMDB and configuration management. Zammad, developed by German company Zammad GmbH, focuses more on multichannel ticketing (email, chat, phone) than on asset management, making it closer to a service desk tool than a full ITIL-aligned ITSM. This mirrors the logic detailed in our comparison of project management software: actual feature scope matters more than the length of a displayed feature list.
“GLPI is listed in the Socle interministériel des logiciels libres, the list of free software recommended by the administration for its information systems.” — DINUM, Socle interministériel des logiciels libres
Total cost of ownership, beyond the license
Comparing an open source ITSM tool to ServiceNow on license price alone gives an incomplete picture. A platform that is free to license still carries infrastructure costs (servers, backups, version upgrades), in-house skills to administer it, and potentially vendor support if the organization does not want to carry operations alone. Conversely, a ServiceNow subscription includes hosting, updates and contracted support, which partly explains the budget gap with open source solutions. The right comparison is made over five years, adding license or subscription, hosting, integration and operations, rather than on the single price shown at the top of a pricing sheet, a calculation logic already developed for CRM software in our CRM software comparison.
Who are these ITSM tools relevant for?
| Profile | Priority | Recommended solution |
|---|---|---|
| IT department managing a service desk and IT assets together | Cutting license cost without losing functional maturity | GLPI |
| Organization with a complex application landscape | Configuration management and CMDB | iTop |
| Support team centralizing multichannel requests | Simple ticketing, email/chat/phone | Zammad |
| Large enterprise with heavily customized business workflows | Advanced orchestration, budget not constrained | ServiceNow |
IT departments looking to cut license costs without sacrificing functional maturity
An organization managing both IT support and its equipment inventory, without wanting to depend on a mandatory SaaS subscription, finds a direct answer in GLPI: service desk and asset management are integrated in the same tool, with no license fee for the self-hosted edition.
Organizations that prioritize configuration management (CMDB)
When CMDB is the central topic, for example to map complex application dependencies, iTop is a credible option, with support available from Combodo or its partners.
Teams looking mainly for a simple multichannel support tool
If the need is limited to centralizing requests coming from several channels (email, chat, phone) without advanced asset management, Zammad addresses that more targeted use case, without the overhead of a full ITSM deployment.
How to choose your ITSM software
Choosing based on migration complexity, not just target features
Organizations already running ServiceNow rarely start from a blank slate: years of custom workflows, integrations and reporting accumulate on top of the core platform. Before comparing GLPI, iTop or Zammad on their respective strengths, it is worth mapping how many of those customizations are genuinely load-bearing versus inherited from defaults nobody revisited. A smaller, well-scoped migration to an open source ITSM tool is far less risky than a like-for-like replication of every ServiceNow workflow, and it is usually where most avoidable project overruns come from.
Mistakes to avoid
- Comparing licenses only without looking at actual feature scope: GLPI, iTop and Zammad are all open source but do not cover the same needs
- Underestimating operating cost: a solution that is free to license still involves hosting, maintenance and upgrade costs, which need to be quantified before comparing with a proprietary vendor’s subscription
- Ignoring data migration: moving away from ServiceNow requires checking the export format of tickets, CMDB records and history before choosing the target tool
- Overlooking the plugin and partner ecosystem: an open source solution with an active ecosystem (plugin marketplace, certified integrator network) reduces the risk of having to build missing connectors with the rest of the information system in-house
Frequently asked questions
What is the best open source ITSM software in 2026?
Three open source ITSM tools stand out in 2026: GLPI, which combines a service desk and IT asset management in a single tool and offers a free self-hosted edition with no user limit, iTop, developed by French vendor Combodo and centered on CMDB, and Zammad, a German tool more focused on multichannel customer support. All three are released under a free software license (GPL or AGPL depending on the tool), unlike ServiceNow, which remains proprietary software available only as SaaS.
Can GLPI replace ServiceNow for a large organization?
GLPI covers the same core processes, incident, request and change management, plus asset management, but its ecosystem of advanced modules remains smaller than ServiceNow’s. It suits organizations that want to standardize their ITSM without paying a proprietary license, including large public sector accounts, but migrating away from ServiceNow requires auditing the specific workflows already built on the platform beforehand.
How much does open source ITSM software cost?
GLPI, iTop and Zammad are all free in their self-hosted edition, with no limit on the number of technicians for GLPI and iTop. The real cost shifts toward hosting, operations and support: each of the three vendors offers a paid subscription (turnkey cloud or tier-3 support) for organizations that prefer to delegate that workload. ServiceNow, by contrast, publishes no public pricing and operates strictly on a quote basis.
Is an open source ITSM reliable enough for a public administration?
GLPI is listed in the Socle interministériel des logiciels libres (SILL), the French government’s list of free software recommended for public administrations, which reflects a level of maturity recognized by the public sector. iTop, developed by a French vendor, is also used by local authorities and public institutions.
Which open source ITSM software should you choose between GLPI, iTop and Zammad?
GLPI is the strongest fit when IT asset management needs to be natively integrated with the service desk, making it the most complete choice for an IT department managing both support and inventory. iTop is relevant when CMDB and configuration management are the priority. Zammad suits teams looking mainly for a simple multichannel ticketing tool.