5 applications that can be replaced by Claude AI.

People use a lot of apps for many different purposes. Managing multiple apps simultaneously is something everyone has experienced. They might use Grammarly for editing, Adobe Acrobat for PDFs, Perplexity for research, note-taking apps (Obsidian, Notion) that are rarely opened, and Pocket for reading content later. Some apps have paid plans, some are free, but all require time and effort to manage, maintain, and switch between.

However, we now have LLM and AI tools like Claude. After using Claude for a while, you'll realize you can use it for much more than just basic functions. For example, instead of just summarizing a long contract, you can ask Claude to annotate the entire contract. You can ask Claude to conduct some competition research before a meeting, and edit an entire article, looking for repeated words and spelling errors all at once. Eventually, you'll use Claude more and other applications less. Here are 5 types of applications that Claude can replace!

1. Grammarly

When you need more than just correcting spelling errors.

Many people have used Grammarly over the past few years in both Pro and Basic modes, and it's a good product. It can detect passive voice, highlight redundant word usage, and suggest more coherent phrasing. However, its capabilities are limited. It often works at the sentence level and doesn't really understand the context of the paragraph or text.

Claude works differently. When you paste a draft in, you can tell it things like "this section is a bit long-winded," "the introduction obscures the main point," or "I need to adjust for a non-technical audience," and it will help adjust the writing on all three at once. Claude can explain why a sentence is ineffective, not just tell you it's ineffective. In addition, Claude can help improve the writing structure: rearranging arguments, shortening the introduction, cutting out words without losing important content, etc. There really is nothing to compare Claude and Grammarly on this level.

2. Adobe Acrobat

200,000 tokens are equivalent to many websites.

Adobe Acrobat is a powerful program. People primarily use Acrobat to read PDFs: long documents, contracts, research papers, user manuals, etc. There is a paid AI assistant that you can purchase from Adobe as an add-on, and it's good enough to extract a line or two, but not so good when you ask follow-up questions.

Claude handles large documents like this quite well. If you pay Claude, the context window can handle 200,000 tokens, equivalent to about 150,000 words. That's a stack of documents most people can't read all at once. You can upload a contract, ask which terms might be unusual for that type of agreement, ask Claude to flag anything that needs review. Consult with a lawyer, then request additional information page by page. The system will keep everything in memory for the conversation.

3. Note-taking applications such as Notion, Obsidian, Roam

Claude's Projects feature does exactly what you've always wanted in a note-taking app.

Many people have tried Notion and Obsidian, Roam Research, and a few others over the past decade or so. Each time, they were excited, spending hours setting up a system (or figuring out how to import from a previous system), using it for a week, and ultimately returning to Apple Notes or TextEdit/Notepad because it was easier to use.

Claude's Projects feature changed that. A Project keeps all relevant documents and context in a consistent space, and the bot can reference it across multiple conversations. For example, if you have a Project for a musical in progress, Claude keeps all your research, interviews, links, background documents, and notes in that space. Claude can pull from the entire thematic dataset when you ask a question. You don't need to manage a bunch of notes and folders just to get help with your project.

4. Readwise

Store things so you can actually use them.

The beloved "read later" app, Pocket, ceased operations in July 2025, forcing many to figure out what they wanted from another app of this type. They didn't need a better inbox, but rather a way to do something with the things they'd saved.

Some people have tried Readwise Reader as an alternative app. It's really useful, has a smooth reading experience, can sync your marked-up sections, and has a feature that helps replay notes over time. It even has a built-in AI layer called Ghostreader. If you like to highlight a lot and want to connect with an extensive note-taking system, Readwise is worth its price.

However, some people save more than 20 articles a week, read about two or three, bookmark one (maybe), and never revisit the rest. The problem isn't with the app, but rather that the system discourages them from using the saved articles.

It turns out Claude can do both. You can paste an article into Claude's conversation window and have a quick chat: What's the main point, what's being assumed, how does it connect to similar articles you've pasted, etc. Keep a Project in Claude where you can add multiple articles to help the AI ​​keep track of more content in its memory.

5. Tools for synthesizing basic research

In-depth research covering multiple fields.

Before Claude and other LLM products, researching topics involved opening numerous browser tabs, extracting information from each tab, and then attempting to manually synthesize it. While this is entirely feasible, it's time-consuming and requires effort that could be used for other tasks. Several AI-powered research tools, such as Perplexity, promise to automate this process, but with inconsistent results, not to mention the constantly changing goals of Deep Research.

Claude's Research and Advanced Research modes work slightly differently from simple searches. Research mode runs multiple linked searches and refines queries along the way, then compiles a structured response with citations. Advanced Research mode, available on higher-tier plans, can run itself for up to 45 minutes across hundreds of sources. Frankly, at this point, the basic Research mode is useful enough, but upgrading would be beneficial if it becomes a necessity in your daily workflow.