A README file is a text document that explains what a software project does and how to use it

When you read code from a website like GitHub or receive a folder of files from a developer, a README is usually the first file you should read. It sits in the main folder and answers the questions someone new to the project will ask: What is this? What does it do? How do I make it work? A README is not code itself — it is plain English (or another language) written for humans to understand the project without having to read through hundreds of lines of technical instructions.

The name comes from the literal instruction: read me first. Most README files are named exactly that — "README" or "README.txt" or "README.md" — so they appear at the top of a folder when sorted alphabetically. Some developers write them in plain text, others use a formatting language called Markdown that adds straightforward styling like bold text and bullet points. Either way, the purpose is the same: to be the entry point for anyone encountering the project for the first time.

Key Takeaways

  • A README file is a text document in the main project folder that explains what the software does and how to set it up.
  • README files are written in plain language, not code, and are meant to be read before you try to use or modify the project.
  • A good README tells you what the project needs to run (like a specific version of Python or Java), how to install it, and how to start using it.
  • The file name is usually "README" or "README.md" so it appears first when you open a project folder.
  • Many README files include examples of how to run the software and where to find help if something breaks.

What information you will typically find in a README

A README usually starts with a one-sentence description of what the project is. Then it explains what problem the project solves or what it lets you do. For example, a README might say "This is a tool that converts photos to black and white" or "This is a library that helps you send emails from Python code."

Next, most README files list the requirements — the things your computer needs to have installed before the project will work. This might be a specific version of Python, Node.js, or Java. It might list libraries or frameworks that need to be present. Without these requirements met, the project will not run, so this section is important to read before you start.

The README then walks through installation — the actual steps to get the project working on your machine. This might mean downloading files, running a command in the terminal, or copying code into a specific folder. A good README gives you the exact commands to type, not just a vague description.

Many README files also include a usage section with examples. If the project is a tool you run from the command line, the README shows you what command to type and what output you should see. If it is code you use inside another program, the README shows you sample code that demonstrates how to use it.

Why developers write README files

A README saves time for everyone. When a developer publishes code, they know that other people — or their future self, months later — will need to understand it quickly. Without a README, someone has to dig through the code itself, read comments scattered throughout, or email the developer with questions. A clear README answers those questions upfront.

README files also signal professionalism. A project with a thorough README looks more trustworthy and more finished than one without. If you are deciding whether to use someone's code in your own project, a good README tells you that the developer cared enough to document their work properly.

For open-source projects — code that anyone can read and modify — a README is essential. It tells contributors what the project is trying to do, how to set up a development environment, and what kind of changes the maintainers are looking for. Without it, potential helpers do not know where to start.

The difference between README and other documentation files

A README is not the only document in a project folder. You might also see a file called "INSTALL" that goes into detail about installation on different operating systems. You might see "CONTRIBUTING" that explains how to submit changes, or "LICENSE" that describes the legal terms for using the code. A "CHANGELOG" lists what has been fixed or added in each new version.

The README is the overview — the place where someone lands first. The other files are deeper dives into specific topics. Think of the README as the table of contents and the introduction combined. It tells you what exists and points you toward the detailed documentation you need.

How to read a README when you encounter one

Start with the description at the top. Does this project do what you need? If not, you can stop there. If it does, read the requirements section and check whether your computer meets them. This takes one minute and saves you from starting a process that will fail halfway through.

Then follow the installation steps exactly as written. Do not skip steps or assume you know a faster way — the README was written by someone who has already done this many times. Copy commands word for word, including capitalization and punctuation. If something fails, read the error message carefully and check whether you missed a requirement.

Once installation is done, move to the usage section and try the examples. Run the exact command or code the README shows you. This confirms that the project is working before you try to do something custom with it. Only after the example works should you try to adapt it to your own needs.

README files in different contexts

A README in a software project on GitHub looks different from a README in a folder of data files or research code. A data README might focus on what each file contains and how the files relate to each other, rather than installation steps. A README for a research project might explain the experiment, the data collected, and how to reproduce the results.

Some README files are very short — just a few sentences and a link to full documentation elsewhere. Others are long and detailed, with sections on troubleshooting, advanced configuration, and how to contribute. The length depends on how complex the project is and how much a new user needs to know to get your free guide.

What stays constant is the purpose: to answer the first questions someone has when they encounter the project. Whether the README is five lines or five pages, it should always be the first place you look.

Frequently Asked Questions

Do I have to read the README before using a project?

You do not have to, but you should. Skipping it usually means you will run into problems that the README would have warned you about, or miss important setup steps. Reading it takes a few minutes and saves you hours of troubleshooting later.

What if a project does not have a README?

If there is no README, the project is harder to use and may not be well-maintained. Look for other documentation files, check if there is a website with instructions, or consider using a different project that is better documented. A missing README is a red flag.

Can I write my own README for a project I am working on?

Yes, and you should. Even if you are the only person using the code now, a README helps you remember how it works when you come back to it months later. Start with a one-sentence description, list the requirements, and write out the installation and usage steps as if you were explaining them to someone else.

Is a README the same as a manual?

No. A README is a quick-start guide that gets you up and running. A manual is longer and more detailed, covering every feature and option. Many projects have both — the README gets you started, and the manual is where you go when you need to know more.

What format should a README be in?

Plain text works fine, but many developers use Markdown because it lets you add formatting like headings, bold text, and links without making the file hard to read. GitHub and other code hosting sites automatically display Markdown README files with nice formatting. Either way, the content matters more than the format.