Choosing which reference manager to use to keep track of your research papers is not a simple choice. In addition to the leading tools in the market, there are more and more smaller reference managers cropping up, each with their own pros and cons. I’ve spent years exploring these tools and perfecting research workflows, and if there’s one thing I’ve learned, it’s this: “Most reference managers are terrible, but some are more useful than others”. In this article, we will compare the existing ones, especially with respect to AI integration.
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If you’re not familiar with the term, a reference manager is software that stores academic papers and books and lets you insert these references into your manuscript. More and more AI is being integrated into these tools, so we are going to look at the main reference managers Zotero, Mendeley, EndNote, Paperpile and Papers, and see how their AI integration works.
Zotero vs Mendeley vs EndNote
2026 UpdateThe AI landscape around reference managers has changed substantially in 2026. Paperpile now includes Ask AI in public beta, which can send selected PDFs directly to ChatGPT/Claude/Gemini. EndNote continues to offer its built-in Research Assistant, while Zotero’s strongest AI options are now its growing plugin ecosystem and connections to external AI agents through MCP.
Here, I’ll compare the “top 3” reference managers, Zotero, Mendeley and EndNote based on their functionality, integrations, and pricing. If you want to jump ahead to my recommendations, click here. I’ll also show a couple of other tools that are worth knowing about. In particular, we’ll look at Paperpile, which is built in a unique way, allowing for certain functionality that other reference managers can’t do.
Here’s a comparison of these reference managers, as they relate to storage, AI integrations, publishing features (i.e. MS Word or Google Doc integration), and note-taking integrations (with Obsidian). I also include a couple of other notable reference managers in the image: Paperpile and Papers. We’ll talk about these in detail below. (This infographic is taken from the Effortless Lit Review course.)
Let’s dive into the details.
Comparison: Pricing and Storage
Mendeley and Zotero allow free usage up to certain storage limits (2GB and 300MB, respectively). EndNote also offers a free web-based version. Zotero currently charges $20/year for 2GB, $60/year for 6GB, or $120/year for unlimited cloud storage. EndNote is considerably more expensive upfront: a full EndNote 2025 licence costs $275 as a one-time purchase, with discounted student and upgrade licences available.
A typical research paper PDF can be anywhere from 2 MB to 20 MB in size, so even 300 MB can be enough for a modest library. Paperpile offers unlimited PDF storage on its paid plans and can also sync your files to Google Drive.
Comparison: Functionality
When it comes to comparing Mendeley vs EndNote vs Zotero, all three share a few key features: they let you maintain a reference library, sync it between devices, and attach or manage PDFs. EndNote, Mendeley and Zotero all let you highlight text, add notes and annotate PDFs. They can also help retrieve PDFs from a reference, and all three support the standard import and export formats used for citations and bibliographies.
Comparison: Writing Integrations
When it comes to integrations, we find some notable differences. All three have integrations with MS Word, but only Zotero and EndNote integrate with Google Docs as well. This is important, because integration with your writing software makes a huge difference when it comes to building out citations and bibliographies in your final manuscript. For example, if you’re confident you’ll be writing your papers in Google Docs, you’ll want to use a reference manager that will integrate with it seamlessly.
👉 Not sure the best software to write your paper in (Google Docs, MS Word, Overleaf, etc.)? You’ll want to check out my guide to writing academic papers faster and better with Google Docs.
Comparison: AI Integrations
A key consideration for your reference manager is how well it integrates with the other tools you’ll be using. EndNote has built-in AI features, while Zotero has a growing ecosystem of third-party AI plugins and integrations. Mendeley does not currently offer a comparable built-in AI assistant.
Most reference managers now offer some route into AI, either directly or through integrations. In 2026, Paperpile added Ask AI, which can send selected PDFs directly to ChatGPT, Claude, Copilot, Gemini or Gemini Notebook; its Google Drive sync also remains useful for working with the broader Google ecosystem. For a wider workflow, see my 2026 guide to using AI for literature review.
Zotero: Pros and Cons
Zotero is one of the most popular reference managers among students and academics. The reason is simple: it’s free. This is especially important for researchers whose institutions don’t provide licenses or access to paid reference managers (like EndNote, for example).
It’s not just the “free” status of Zotero that makes it so great though. Zotero is powerful, flexible, easy to use, and fast. It has many plugins and extensions that allow seamless integration into broader research workflows, including direct integrations with MS Word and Google Docs. However, the Google Docs integration can become slow in larger documents, where Paperpile is often more convenient.
👉 I cover how to connect your reference manager, PDFs and notes into a broader research system in the Information Management course.
Zotero has a few notable drawbacks though;
- Zotero’s free cloud storage is capped at 300MB. Local storage is uncapped, but for any integrations (like the ones above), you may start to feel this limit around a few hundred PDFs.
- Integrations can sometimes be unreliable, especially Google Docs.
- The software can slow down with large documents.
- Third-party plugins can occasionally lag behind Zotero’s increasingly rapid release cycle, so compatibility is worth checking before a major update.
Overall, Zotero is an excellent option if you’re confident you don’t want to spend any money on a reference manager. Choose Zotero, and don’t look back.
How to integrate AI into Zotero
ARIA is no longer my recommended way to add AI to Zotero: its latest stable release dates from 2024, and compatibility issues have been reported with newer Zotero and OpenAI versions. In 2026, stronger options include dedicated Zotero AI plugins as well as connecting your library to external agents through MCP.
👉 See my Best Zotero Plugins for 2026 for current options, or my guide to connecting your local Zotero library to Claude.
Mendeley: Pros and Cons
Mendeley is another popular reference manager choice for academics, which, in my opinion, is not a particularly compelling choice in 2026. Since being acquired by Elsevier in 2013, its feature set has remained focused on the fundamentals: PDF management, annotation, note-taking, cloud sync and Microsoft Word integration. Mendeley Reference Manager is still actively maintained, but it has no comparable built-in AI assistant and is not supported on mobile devices.
Like Zotero, Mendeley offers MS Word integration, allowing you to cite references from your Mendeley library directly in your manuscript. One of its other benefits is the relatively generous free storage capacity: you can store up to 2GB of references, significantly more than Zotero’s free cloud-storage limit.
Compared to the other tools, it just doesn’t have the same availability of integrations. There is no integration for Google Docs, and no AI integration. Perhaps these features will be coming to Mendeley Reference Manager, but for now, if you value integrating your reference manager easily into other parts of your research workflow (and use AI tools), you may want to think carefully before committing to this one.
EndNote
EndNote, when compared to Mendeley and Zotero, can be viewed as the “premium version”. It offers no free desktop version, but it does have an online version. A full EndNote 2025 licence currently costs $275 as a one-time purchase; the student licence is $175 and upgrades are $150. Many universities purchase EndNote licences on behalf of their researchers, so check whether your institution already provides access.
When it comes to functionality, EndNote offers the same core features as Mendeley and Zotero. One of the key benefits compared to the other tools is its built-in AI Research Assistant. This relatively new feature allows for paper summarisation and analysis within the application. It’s akin to any “chat with PDF” AI, letting you ask questions about your topic, with answers coming based on the PDF. However, compared to other AI tools you can find online, the functionality is rather limited and simple.
EndNote also offers direct integrations with MS Word and Google Docs (like Zotero), making writing and publishing easier.
Paperpile Reference Manager: Pros and Cons
Paperpile is a web-based reference manager that differs from EndNote, Mendeley and Zotero through its particularly tight integration with Google’s ecosystem. PDFs can be synced to Google Drive, where they remain accessible to other apps and AI tools. Although Paperpile does not have a traditional desktop application, it also has dedicated mobile apps and integrations for Word and Google Docs.
Paperpile also integrates easily into the writing process, especially if you work in Google Docs. Its citation integration is one of its strongest features, while Google Drive sync makes your PDFs easy to reuse across the rest of your research workflow.
👉 I cover how to connect your reference manager with a long-term system for PDFs and notes in the Information Management course.
Paperpile and AI
In 2026, Paperpile added Ask AI in public beta, allowing you to send selected PDFs directly to ChatGPT, Claude, Copilot, Gemini or Gemini Notebook. Google Drive sync remains another useful route into Google’s AI ecosystem, particularly if you already work in Gemini and Google Docs.
If you open a synced PDF in Google Drive or another external viewer, you will not be using Paperpile’s own annotation interface. However, annotations written directly into the PDF can still be visible across compatible viewers once the file syncs back.
One downside of Paperpile is that it offers no permanent free tier, although there is a 30-day trial. The Regular plan costs $8.30/month billed annually, or $4.15/month with the 50% academic discount; the Expert plan costs $11.50/month, or $5.75/month with the academic discount.
How to Switch Reference Managers
Some reference managers offer you the option to migrate, as Zotero is the reference manager that most academics use. Most reference managers will offer an option to import from Zotero. In that case, you will keep the folder structure, and all your PDFs and papers will be migrated seamlessly. (Here is how to go from Zotero/Mendeley→Paperpile ) Your notes, however, will not.
Other reference managers, like Mendeley, let you set up a folder that monitors incoming PDFs. That means if you export all your PDFs into this folder, they will be automatically picked up by the reference manager. If your Paperpile PDFs are synced to Google Drive and then to your computer, you can point Mendeley at that folder to import the files automatically. However, your tags, folders, and annotations may not migrate cleanly.
Generally, every reference manager supports exporting your library metadata to a standard format such as BibTeX or RIS. These exports contain citation metadata but usually not the PDF files themselves, so moving references is much easier than moving your complete library with annotations and attachments intact.
Moving from one reference manager to another is not a big project unless you rely heavily on tags, folders and annotations inside your current reference manager. I generally suggest making your note-taking system the main organisational layer for what you learn from papers, rather than relying entirely on the reference manager.
How I evaluate reference managers
After exploring Zotero, Mendeley, and EndNote as reference manager options, you may have noticed one key question we keep coming back to: How well does it integrate into our research workflow?
These integrations may seem superfluous at the start of the project, but they become massive time-savers down the road. Each time you find and save a new paper, you’ll need to conduct analysis, incorporate it into your notes, and finally write about it and cite it appropriately in your final manuscript. Traditionally, this process was unavoidably painful and tedious. With the right tool integrations, this process now becomes effortless.
So, the question remains: which reference manager integrates best to our research workflow?
In my opinion, after evaluating these options, I’ve found a clear winner: Paperpile.
Paperpile remains particularly strong if you work inside Google’s ecosystem. Google Drive sync makes your PDFs accessible to other tools, while Ask AI now provides a more direct route from selected papers into ChatGPT, Claude, Copilot, Gemini and Gemini Notebook.
👉 If you want to connect reference management with a durable system for organising papers, notes and ideas, checkout the latest Information Management course. It leads you up Obsidian’s learning curve with ease, empowering you to build a full-fledged and deeply personal knowledge management system.
Bottom line: Which reference manager should I use?
If you’re like me, and want to accelerate tedious, repetitive tasks, and enhance your research process by using AI, then I think there are two clear winners as the best reference managers to use.
If you’re willing to pay, go with Paperpile. Its excellent Google Docs integration, optional Google Drive sync and new Ask AI workflow make it a particularly strong choice if you work heavily inside Google’s ecosystem.
If you want to stick to a free option, go with Zotero. It’s one of the most popular choices among academics, and for good reason; with free storage (up to a limit), reliable functionality, and a huge array of integrations, Zotero is also easy to work into most research workflows.
Both choices can integrate with a broader note-taking setup built around Obsidian. 👉 If you want to build that system from scratch, start with my free 21-day course.
The AI gap is smaller in 2026 than it used to be: EndNote has a built-in Research Assistant, Paperpile has Ask AI, and Zotero has much stronger plugin and MCP options. For the broader workflow beyond the reference manager itself, see my guide to using AI for literature review in 2026 or connecting a Zotero library directly to Claude.
