# What Types of Resources Are Explicitly Rejected from the Free Programming Books List? > Discover what resources are rejected from the free programming books list Avoid non-free content email registration links and more Learn what qualifies for inclusion - Repository: [Free Ebook Foundation/free-programming-books](https://github.com/EbookFoundation/free-programming-books) - Tags: best-practices - Published: 2026-02-23 --- **The Free Programming Books repository rejects non-free content, file-hosting service links, URL shorteners, resources requiring mandatory email registration, and any contributions violating the Code of Conduct.** The EbookFoundation/free-programming-books project maintains strict curation standards to ensure every listed resource is genuinely accessible. Understanding what types of resources are explicitly rejected from the list helps contributors avoid common pitfalls and speeds up the review process. These exclusions are formally defined in the project's contribution guidelines and enforced through automated linting. ## Categories of Rejected Resources ### Non-Free Content and Paywalled Material The repository strictly prohibits links to content that is not freely available. According to [`docs/CONTRIBUTING.md`](https://github.com/EbookFoundation/free-programming-books/blob/main/docs/CONTRIBUTING.md), the project only accepts resources that provide a free copy of the book or course without payment barriers. Specifically, the guidelines state: *"We do not accept links to pages that require working email addresses to obtain books"* without proper annotation. ### File-Hosting Services and Upload Platforms Links pointing to generic file-upload platforms are explicitly banned. The guidelines in [`docs/CONTRIBUTING.md`](https://github.com/EbookFoundation/free-programming-books/blob/main/docs/CONTRIBUTING.md) list specific prohibited services: **Google Drive, Dropbox, Mega, Scribd, and Issuu**. The documentation clarifies: *"We don't accept files hosted on Google Drive, Dropbox, Mega, Scribd, Issuu and other similar file upload platforms."* This rule prevents link rot and ensures resources remain accessible through official channels. ### URL Shorteners and Obfuscated Links The repository rejects any links that use URL shortening services. The [`docs/CONTRIBUTING.md`](https://github.com/EbookFoundation/free-programming-books/blob/main/docs/CONTRIBUTING.md) file explicitly states: *"no URL shortener links."* This policy ensures transparency about the final destination and prevents potential security risks associated with obfuscated URLs. ### Gated Resources Requiring Mandatory Registration Resources that force users to register or provide an email address before downloading are rejected unless properly annotated. The guidelines specify that if an *"email address or account setup is requested before download is enabled,"* contributors must add a note in parentheses such as `*(email address requested, not required)*`. Plain links that enforce mandatory registration without this disclaimer are rejected during review. ### Code of Conduct Violations Beyond content type, the repository rejects any contribution violating community standards. According to [`docs/CODE_OF_CONDUCT.md`](https://github.com/EbookFoundation/free-programming-books/blob/main/docs/CODE_OF_CONDUCT.md), project maintainers have the right to *"reject comments, commits, code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct."* This includes harassing content, hate speech, or other unacceptable behavior. ## Where These Rules Are Documented The exclusion criteria are formally defined in two key files: - **[`docs/CONTRIBUTING.md`](https://github.com/EbookFoundation/free-programming-books/blob/main/docs/CONTRIBUTING.md)** – Contains detailed guidelines on allowed links, including the ban on file-hosting services, URL shorteners, and non-free resources. - **[`docs/CODE_OF_CONDUCT.md`](https://github.com/EbookFoundation/free-programming-books/blob/main/docs/CODE_OF_CONDUCT.md)** – Defines behavioral standards and explicitly grants maintainers authority to reject violations. ## Automated Enforcement These rules are not merely suggestions; they are enforced automatically. The repository uses GitHub Actions workflows (defined in [`.github/workflows/lint.yml`](https://github.com/EbookFoundation/free-programming-books/blob/main/.github/workflows/lint.yml)) to run linters that check submissions against these criteria. Contributions violating the file-hosting, URL shortener, or formatting rules are automatically flagged and rejected during the pull request review process. ## Correct vs. Incorrect Submission Examples The following examples demonstrate the difference between rejected and accepted resource submissions. **Rejected: File-hosting service link** ```markdown * [Secret PDF](https://drive.google.com/file/d/ABC123/view) - John Doe (PDF) ``` *Reason:* Uses Google Drive, which is explicitly prohibited. **Accepted: Direct author link** ```markdown * [Open-Source Book (2022)](https://example.com/book.pdf) - Jane Doe (PDF) (CC BY) ``` *Reason:* Direct link to free PDF on author's site, includes year and license, no prohibited platforms. **Rejected: Mandatory email gate** ```markdown * [Restricted Book](https://example.com/download) - John Doe (PDF) ``` *Reason:* Download requires mandatory email registration without annotation. **Accepted: Email gate with disclaimer** ```markdown * [Restricted Book](https://example.com/download) - John Doe (PDF) *(email address requested, not required)* ``` *Reason:* Note clarifies the access requirement, complying with annotation guidelines. ## Summary - **Non-free content** requiring payment or mandatory email registration (without note) is rejected. - **File-hosting services** including Google Drive, Dropbox, Mega, Scribd, and Issuu are prohibited. - **URL shorteners** are banned to ensure link transparency. - **Code of Conduct violations** result in immediate rejection of contributions. - Rules are documented in [`docs/CONTRIBUTING.md`](https://github.com/EbookFoundation/free-programming-books/blob/main/docs/CONTRIBUTING.md) and [`docs/CODE_OF_CONDUCT.md`](https://github.com/EbookFoundation/free-programming-books/blob/main/docs/CODE_OF_CONDUCT.md) and enforced via GitHub Actions. ## Frequently Asked Questions ### Why does the repository reject Google Drive and Dropbox links? The project bans these platforms to prevent link rot and ensure long-term accessibility. File-hosting links often become unavailable when accounts are deleted or storage limits are reached, whereas direct links to author or publisher sites remain stable. ### Can I submit a resource that requires an email address if it's still free? Yes, but only if you include a specific annotation. According to [`docs/CONTRIBUTING.md`](https://github.com/EbookFoundation/free-programming-books/blob/main/docs/CONTRIBUTING.md), you must add a note such as `*(email address requested, not required)*` to inform users about the registration requirement. Submissions without this disclaimer are rejected. ### What happens if my contribution violates the Code of Conduct? Project maintainers have the explicit authority to reject any comment, commit, code, wiki edit, issue, or other contribution that violates the standards defined in [`docs/CODE_OF_CONDUCT.md`](https://github.com/EbookFoundation/free-programming-books/blob/main/docs/CODE_OF_CONDUCT.md). Violations may result in immediate rejection of the pull request and potential banning from further participation. ### Are PDF files from personal websites allowed? Yes, provided the PDF is freely accessible and the website is the author's official or primary distribution channel. The link must not require payment, mandatory registration (without note), or be hosted on prohibited file-sharing platforms. Direct PDF links from personal domains are preferred over third-party hosting services.