Reading notes
The standards behind your reading data: ISBN, CSV, OAuth and privacy labels
Four shared formats and rules that decide how your books are identified, moved, connected and described.
Best Book Tracker Apps editors · 10 February 2026 · 4 min read
Four standards sit under every book tracker. The ISBN identifies the edition you are reading, a CSV file carries your library from one app to another, OAuth lets apps connect without sharing your password, and App Store privacy labels describe what an app collects. Knowing what each one does helps you move apps safely and read a listing with a sharper eye.
Contents
Why do standards matter to readers?
Standards are the reason your reading history is not locked inside one app. A barcode scan works because every edition carries a standard number, an import works because apps agree on a file format, and a listing's privacy section is comparable because every developer fills in the same headings. When an app supports the common standard, you can leave it easily. When it does not, you depend on its own tools.
What is an ISBN and why does it matter?
The International Standard Book Number identifies a specific edition of a book, so the hardcover, paperback, ebook and audiobook can each have their own. Since January 1, 2007, new ISBNs have 13 digits, matching the EAN-13 barcode printed on the back cover. When you scan a barcode in The StoryGraph, Goodreads, Literal, Bookly or BookBuddy, the app reads that number and looks the edition up; BookBuddy's lookups are backed by WorldCat, a union catalogue of library collections run by OCLC.
For your stats, the edition matters: page counts differ between editions, so scanning the copy in your hands keeps your page progress honest. See the glossary entry for ISBN.
What is a CSV file and why is it the way out?
A CSV file is a plain-text table with one row per book and commas between the fields. The format is documented in RFC 4180, published in October 2005. It is the closest thing reading apps have to a common exchange format: Goodreads exports your library as CSV, The StoryGraph emails you a CSV export on request, BookBuddy imports and exports CSV, Fable accepts a Goodreads CSV, and Literal accepts a StoryGraph CSV.
Because it is plain text, a CSV file opens in any spreadsheet, which makes it the best backup you can keep. Export once a quarter and store the file somewhere you control.
What do APIs and OAuth add?
An API lets software read or write your data in an app directly, without a file in between. OAuth is the open standard that lets you approve that access without handing over your password; OAuth 2.0 is published as RFC 6749 (October 2012). Hardcover publishes a GraphQL API with OAuth, and Literal publishes API documentation for developers. Goodreads stopped issuing new API keys in December 2020, so its data now leaves mainly through the CSV export.
Most readers never touch an API. It still matters, because it is what lets other tools, from spreadsheets to personal dashboards, connect to your reading history.
What are App Store privacy labels?
Apple asks every developer to describe its data practices in the App Privacy section of the listing, under up to three headings: data used to track you, data linked to you and data not linked to you. On iPhone, Apple's App Tracking Transparency prompt, in place since iOS 14.5, asks your permission before an app tracks you across other companies' apps and websites.
The labels are self-reported, and Apple notes they may not describe all of a developer's practices, but they are the one consistent public record across every app we rank. That is why our privacy criterion, weighted 10 out of 100, is built on them. Hardcover scores highest with BookBuddy at 9; our article on reading app privacy labels covers all nine apps.
What should you do with this?
- Scan barcodes rather than searching by title, so the edition is right.
- Export your library as CSV once a quarter, and before any move.
- Before approving a connection between two apps, check what access it asks for, and remove connections you no longer use.
- Read the App Privacy section of any new reading app before you download it, starting with data used to track you.