Need a CRM that fits your business—not the other way around? We tested the top open-source options of 2025 to find the most customizable, developer-friendly solutions.
Why Use An Open-Source CRM?
If you’re looking for open-source CRM software, you’re probably in one of these situations:
You’re running a small business, and you need a of CRM to manage your customer relationships, but you want the tool to adapt to your business and not the other way around. You have some basic technical skills, and you’re not afraid to get your hands dirty.
You're already a user of commercial CRM software, and you’re looking for a more flexible and cost-effective solution. You're ready to invest some time and money to migrate your data and adapt the software to your needs.
You're not a coder, and you're only looking for a free CRM.
This benchmark is for you if you're in the first two situations, as it focuses on the ability to modify the software using code beyond what the user interface allows.
Selecting Open-Source CRMs
We selected open-source projects that encourage and support modifying their code. The choice is surprisingly limited, as most editors use the word "open source" as a synonym for "free tier" but don't really want you to modify their code.
Target Audience: Small to Medium Businesses: Large corporate companies have very specific needs and can afford to pay for a commercial CRM. We focused on CRMs suitable for small to medium businesses.
Really Open-Source: We only considered CRMs that provide an easy-to-find repository for their source code. The repository must be active, with a reasonable number of contributors, a regular release cycle, and a short time to fix security issues.
Developer Documentation: Only projects that provide clear and up-to-date documentation were considered.
Active Community: Some projects are developed in-house, in a closed environment, and the source code is only published as a second thought. We only considered projects with an active repository, a public bug tracker accepting external contributions, and a public roadmap.
Easy Start: A full-stack developer should be able to download and launch the CRM in less than 30 minutes. We only considered projects that provide a simple way to start the CRM locally.
Easy Hosting: Some open-source frameworks are notably hard to host (I'm looking at you, Next.js). We only considered projects that can be hosted in any Linux host with a few commands.
English Interface: Many CRM projects are only available in French, Polish, or Russian. We only considered projects that are available for an international audience and support at least English and, ideally, other languages.
Minimal Features: We only considered projects that cover at least the basic CRM features: contacts, companies, deals, notes, file attachments, and import/export. We didn't consider projects that are too specialized (for example, only for real estate or non-profits).
Based on these criteria, we selected the following open-source CRMs for evaluation, which we list in order of preference:
Disclaimer: We're the editors of Atomic CRM, one of the CRMs mentioned in this benchmark. We tried to be as objective as possible, but we're not neutral. We're also not affiliated with any other projects mentioned in this benchmark.
Twenty's popularity is growing, and for good reasons: they move fast and clearly identify developers as key users. The codebase is clean and well-documented, although quite big for the feature set. The project is still young but is already a solid choice for a small to medium business. Too bad they're using a contaminant license!
Atomic CRM leverages modern technologies to minimize the code required to build a CMS (only 15k LOC for a complete solution). As a consequence, it's easy to learn and easy to customize. See it as a perfect template to build your own CRM rather than a full-featured CRM that you'll spend months to adapt to your needs.
EspoCRM is a very complete CRM with a simple user interface. The powerful in-app administration allows you to customize pretty much everything. If its features match your needs, it's a great choice. However, the codebase is quite large, uses homemade backend and frontend frameworks, and the documentation is limited, so even simple code customizations can be challenging.
OroCRM is part of OroCommerce, a B2B eCommerce platform. While it includes basic CRM features, the primary focus is on eCommerce. Despite using modern coding practices, the extensive and complex codebase makes customization challenging, especially for basic CRM features.
SuiteCRM is the successor of the popular SugarCRM, open-source until 2014. Its legacy is both a chance and a burden: it has a large user base and many features, but the codebase is old and uses outdated coding practices. It is probably not the best candidate for a simple CRM.
Odoo is a behemoth CRM that covers pretty much every feature you can think of. It's also an ERP, with modules covering finance, supply chain, point of sale, human resources, marketing, and even a website builder! The main consequence is that the codebase is huge. Most Odoo projects are carried out by specialized Odoo developers who make a career out of it. It's a good fit for large companies that need an integrated solution but not for small businesses.
ERPNext is designed to be the central hub for all your business needs, from CRM to accounting, inventory, project management, and more. But if you're only looking for a CRM, it's way too complex, and the workflow is too rigid. Finally, it's not easy to dive in and start customizing the code.
Axelor is another ERP / BMP low-code platform with a CRM module. Even though it's open-source, it's not really designed for developers to modify the code. The codebase is enormous, and the documentation is limited. It's a good fit for companies that need a lot of features and are ready to pay for the enterprise version.
Commercial CRMs with a free tier (Hubspot, Monday, Zoho, Salesforce, etc.)
Conclusion
None of the open-source CRMs we tested achieved a 10/10. You'll have to make compromises.
This benchmark shows that there are very few open-source CMS that a company can modify without publishing its changes (Atomic CRM and Odoo). Most open-source CRMs rely on a huge codebase, which makes them hard to customize. In addition, many of them rely on non-standard frameworks, so finding developers and training them will be a challenge.
But there is hope! The top three CRMs in this benchmark (Twenty, Atomic CRM, and EspoCRM) are good choices for a small to medium business. If you're looking for a CRM that you can modify to fit your business, you should start with one of these three.
