Kick off your book project in 3 hours! Live workshop on Zoom. You’ll leave with a real book project, progress on your first chapter, and a clear plan to keep going. Saturday, May 2, 2026. Learn more…
A Short Guide to Naming
Understand how and why to better name modules, classes, functions, and variables.
if you've read my chapter on naming in a famous software book (first or second edition) you may want to go a little deeper. Same author, same topic, all-new content!
#1 Best Seller in Management Science (Amazon International, France, Germany, Netherlands, Poland, Sweden – Feb 2026) and in other categories. Available worldwide on Amazon (Hardcover, Paperback, Kindle) and across all major digital platforms, including Leanpub, Apple Books, and Google Play. Learn how to drive your organizational performance with people and AI to 10X and beyond — in impact and relevance.
What makes a software engineer truly effective? Beyond writing code, effectiveness comes from ethics, sustainable practices, collaboration, and the courage to adapt. The Effective Software Engineer guides you from clean coding habits to organizational empowerment, bridging the gap between developers and leaders.
AI can generate code faster than ever. But speed is no longer the hardest part of software development.The real challenge is building systems where generated code remains correct, controlled, and aligned with architectural intent. Becoming a Harness-Driven Developer introduces a new development model for the age of AI-assisted engineering - one where developers focus less on writing every line by hand and more on defining the rules, structure, and enforcement mechanisms within which AI code agents operate.Through a practical repository mapped directly to the book’s chapters, this book shows how to move from ad hoc coding to a harness-driven approach based on specification, architecture, invariants, controlled execution, and system evolution. This is a book about staying in control while software development changes.
What was so unusual and special about Cray Research? We accomplished, repeatedly, what nobody else on the planet was able to match. High-Performance Computing is not merely parallelism and large-scale systems. That is the public-facing decoy version.
Logic is the most important branch of math to software engineering. Knowing logic opens up a vast world of development techniques, from everyday tricks of the trade to exotic tools for cracking impossible tasks. This book teaches the basics of logic and nine special logic-powered techniques: property testing, decision tables, constraint solving, and more. Over 50 exercises are provided to help readers master the material. No prior math background required!
A practical handbook packed with real-world advice to help you write better code, adopt effective developer habits, and build great software.
This book opens the door for developers, project managers, product managers, and business analysts who want to understand how trading systems really work — from trade booking and lifecycle processing to data flow and integration. It provides the knowledge and perspective needed to gain a true edge in one of the most technically sophisticated domains in finance.
Residuality Theory is a new way to think about the design of software systems that explains why we experience design the way we do, why certain things seem to work only sporadically, and why certain architects get it right so often regardless of which tools they use. A new, scientific approach is defined that fuses Software Engineering, Complexity Science, and Philosophy to produce an entirely new way to think about how to design software. The result is a theoretical base that allows architecture to finally become its own discipline.
Capable people drift into failure through accumulated lapses in attention. By the time collapse becomes visible, erosion has been active for years. Ishi is the discipline that interrupts drift before collapse forces correction.
Spring Boot 4 changes everything you thought you knew about building Java applications. Virtual threads make blocking code fast again. Native images deliver instant startup. First-class API versioning finally solves the "how do we evolve our APIs?" problem. But here's the catch: upgrading isn't just a dependency bump. Jakarta EE 11, new auto-configuration patterns, GraalVM constraints, and reactive vs. virtual threads— getting it right requires understanding the *why* behind every change. This book is your production-ready guide to Spring Boot 4 and Spring Framework 7. Written for intermediate developers who need more than "hello world" tutorials. Learn how to: • Build cloud-native microservices that scale • Migrate from Boot 3 safely and incrementally • Design APIs with built-in versioning and resilience • Choose between reactive, virtual threads, and native images • Secure distributed systems with JWT and OAuth2 • Implement observability that actually helps you debug production issues 300+ pages. 27 chapters. Real code. Real architecture. Real problems solved.
800 pages. 11 chapters. The full forecasting stack in Python — from ARIMA to foundation models — with production-grade code and proper evaluation. No hype.
You’ll just need the Five Essential Elements of Learning Through five essential elements, you’ll gain the ability to learn anything deeply—no matter how complex the subject. These five pillars of effective learning will become lifelong tools, guiding you every time you set out to truly master new knowledge and retain it permanently. If you're ready to stop passively consuming information and start truly mastering it, this book is for you.
You've got forty vendors, a hundred integrations, and a SOC 2 report that tells you exactly nothing about what happens when one of them gets compromised. Your dependency map lives in someone's head. Your exposure estimate is a shrug. Your decision process is whoever talks loudest in the emergency meeting. And when it's over, every lesson learned evaporates before the next incident hits. Someone Else's Breach is the framework that replaces all of it — a quantitative, repeatable system for knowing what you're exposed to, deciding what to do about it, and getting better every time. From proactive resilience design to AI-augmented detection, this is the practitioner's guide to surviving incidents you didn't cause but can't ignore.
With more than 1200 microcontrollers, STM32 is probably the most complete ARM Cortex-M platform on the market. This book aims to be the most complete guide around introducing the reader to this exciting MCU portfolio from ST Microelectronics and its official CubeHAL and STM32CubeIDE development environment.
The practitioner's guide to Claude Code in production. Thirty chapters covering the agent loop, tools, hooks, MCP, permissions, evals, observability, and cost engineering for AI agents that actually scale.
Чому проєкт-цукерочка через рік перетворюється на непідтримуване пекло? Тому що вас ніколи не вчили базі. Ця книга — єдина система координат, яка нарешті збере ваші розрізнені знання про ООП, GRASP, SOLID та GoF в одну цілісну картину.
Learn SysML v2 with the ultimate guide for all skill levels in MBSE. Authored by insiders, it's your key to unlocking the full potential of system modeling and a passport to mastering your MBSE.
The book covers every topic in the latest CISSP exam syllabus, organized in a format that makes it easy to drill down on specific exam domains and concepts at-a-glance, making it an essential exam resource for anyone who aims to prepare for the exam without wasting time or money.
A complete foundation for Statistics, also serving as a foundation for Data Science. Leanpub revenue supports OpenIntro (US-based nonprofit) so we can provide free desk copies to teachers interested in using OpenIntro Statistics in the classroom and expand the project to support free textbooks in other subjects. More resources: openintro.org.
A clear, illustrated guide to large language models, covering key concepts and practical applications. Ideal for projects, interviews, or personal learning.
The Rails™ 8 Way is the comprehensive, authoritative reference guide for professionals delivering production-quality code using modern Ruby on Rails. It illuminates the entire Rails 8 API, its most powerful idioms, design approaches, and libraries. Building on the previous editions, this edition has been heavily refactored and updated.
Skip the black-box frameworks. Build a production-grade AI coding agent from scratch in pure Python - cloud or local, tested with pytest, all in a single file.
Big Kotlin pack
The following 5 books are included in this bundle...
Piotr Jablonski, Lukasz Bromirski, and Nick Russo have joined forces to deliver the only CCIE Service Provider training resource you'll ever need. This bundle contains a detailed and challenging collection of workbook labs, plus an extensively detailed technical reference guide. All of us have earned the CCIE Service Provider certification...
If you are introverted and ambitious and you want to learn how the best one-person founders create explosive online businesses - with passive income elements - this is the perfect bundle for you.
The Quality Software Bundle is for managers, would-be managers, and any of us who find themselves being managed and confused. This comprehensive bundle covers the entire span of software development approaches, from hacking through waterfall, cascade, prototyping, Iterative enhancement, reusable code, off-the-shelf, to Agile teams. The bundle...
Longitudinal Data Analysis in R + combines a comprehensive, hands-on guide with a concise cheat sheet to give you both depth and clarity. Learn how to prepare, explore, and model longitudinal data using real-world examples in R—while always having a clear map of key concepts, commands, and models at hand.
This bundle includes the books “Residues: Time, Change and Uncertainty in Software Architecture” and “The Architect’s Paradox: Uncertainty and the Philosophy of Software Architecture” by Barry M O’Reilly. The books complement each other, with Residues giving a practical description of how to apply residuality theory and The Architect’s Paradox...
Build, test, and package Rust the professional way, then accelerate with 100+ practical solutions across performance, CI/CD, and service-style patterns. Add network programming and automation skills, including protocols and packet analysis, so our Rust can power real infrastructure.
Interviews with Leanpub authors and special guests
The Leanpub Podcast
Sal Kimmich, Author of Code, Chips and Control: The Security Posture of Digital Isolation
Sal Kimmich - In this episode of the Leanpub Podcast, Sal Kimmich explains how modern computer chip supply-chain threats, insecure defaults, and fragmented trust models shape today’s cybersecurity posture. They discuss digital isolation, open-source governance, and practical strategies for building resilient, verifiable systems.
Hands-on online course to learn all you need to know to get a Spring Boot application into production with AWS. Visit our landing page for a tour of the contents. Make sure to get familiar with all available bundle options before enrolling.
Master language models through mathematics, illustrations, and code―and build your own from scratch! This course includes nearly three hours of exclusive video interviews with the author, covering questions related to each of the six lessons included in the course.
Unlock the power of AI in your applications with this groundbreaking course on AI-driven application architecture. Discover practical patterns and principles for building intelligent, adaptive, and user-centric software systems that harness the potential of large language models. This course includes exclusive video interviews with the author.
This is a fast-paced, practical, and visual guide to the strange new world of Generative AI. It is like an extended version of Henrik's viral video with the same name.
Microservices are a great approach for building software at scale. But although the ideas at the root of microservices may sound simple, this is not a simple approach. There are several big traps along the way, and it's important to avoid them...
To ace your next Android developer job interview, focus on truly understanding the concepts, not just memorizing answers, and practicing how to apply them. With over 250 quiz questions, 370 practical and follow-up questions with full answers, and 60+ pro tips, this course helps you sharpen skills, understand the why, and prepare for real-world technical challenges. ISBN: 979-8285926436
This course gives you an intuitive understanding of the eight most important machine learning algorithms. It helps you get started using them in your own projects NOW -- in a single line of Python code. After finishing this course, you'll be able to select, understand, and implement the top 8 machine learning algorithms in your own projects.
This course is based on the 2025 edition of the best-selling Kubernetes book, that has been fully updated for the latest versions of Kubernetes and the latest industry trends. You won't find a better and more up-to-date book-based course on Kubernetes. Hand-crafted over the past 8 years by best-selling author Nigel Poulton.
Takes you from "how to use Kotlin" into "how Kotlin really works," revealing internal implementations, demystifying bytecode and compiler behavior, and uncovering the internals that shape the language. With hands-on Code Playgrounds for immediate practice and 158 interactive assessments to test and reinforce your understanding, this course doesn't just show you why everything is the way it is, it challenges you to prove you've mastered it. ISBN: 979-8243872744
Become a Leanpub author
Leanpub makes it easy to create, publish, and sell ebooks or online courses while earning industry-leading royalties. With 80% royalties on purchases of $7.99 or more (or 80% minus a small $0.50 fee for purchases under $7.99), your work earns what it deserves. For example, a $10 sale brings you $8, and selling 5,000 copies at $20 could mean $80,000 in your pocket!
Leanpub has already paid out $15,378,745.34 to authors. Whether you write in Markdown or upload PDF/EPUB files, Leanpub’s intuitive publishing tools simplify the process. Use our in-browser editor or sync with GitHub or Dropbox and publish your ebook with a single click. Plus, you decide when to release—during the writing process or upon completion.
Learn MoreAs an academic, I like Leanpub because it lets me write and get my ideas out there quickly. Leanpub is simply the best place for publishing my books.
WPF + MVVM
This track includes the following 2 courses...
About the Track: AI Masterclass Artificial Intelligence is reshaping the way we live, work, and build technology. The AI Masterclass Track brings together three powerful courses from world-class experts to give you a comprehensive, practical, and hands-on education in the age of AI. Whether you want to understand the big picture, apply AI...
Taking this bundle, you'll get a comprehensive set of courses that cover almost the whole surface of the .NET framework.The big topics that are covered:WPFMVVMSpecFlow and SeleniumLINQMultithreading and Parallel ProgrammingC# in Depth: Puzzles and GotchasAlgorithms and Data Structures in C#VS and R#and engineering practices:Unit Testing with...
This is the complete track to learn about essential Kotlin features and get ready for working in Kotlin in daily basis. It starts from essentials, and on the way reaches advanced topics like efficient collection processing or DSL creation.
"Shut up and code." Laughter in the audience. The hacker had just plugged in his notebook and started sharing his screen to present his super-smart Python script. "Shut up and code" The letters written in a white literal coding font on black background was the hackers' home screen background mantra. At the time, I was a first-year computer...
Learn Python the Practical Way - In this course you learn all the basics of the Python programming language. It contains exercises, explanatory videos, an example solution and a quiz. This will enable you to apply your skills to a wide range of real world problems.A collection of more Python exercises - Exercises with solutions to continue...
Python is the fastest-growing major programming language on the planet. This practical course set will teach you Python in a hands-on, highly practical way that guarantees your success. All you need to go from zero to completing your own Python projects in a relaxed, student-centric, and fun environment. Create yourself a new skill that'll bring...
Taking this course bundle, you'll learn:SOLID principles (SRP, OCP, ISP, LSP, DIP) in-depthMeta principles: DRY, KISS, YAGNI, SoC, CQS, Law of Demeter, PoLADependency Injection in Depth: IoC or DI containers, best practices, and anti-patternsFunctional Programming in C#: purity and side effects, functional C# features, immutability,...
This is the perfect Game Studio starter kit for launching your online dream business. This kit contains 6 tutorials books to help you create 9 different online game mechanics. You could have all 9 games ready in a day for each game. Start your Game Studio today.
Learn both WPF and MVVM to build fully functional UI-applications with the modern UI-building framework, Windows Presentation Foundation (WPF).MVVM will help you to build WPF apps in a correct way from the software design perspective.
With about 2000 books which are Free With Membership and credits for the rest, the real question is: How many credits do you want?
A Mini Reader Membership includes access to about 2000 books on Leanpub that are Free With Membership, and includes 1 book credit every 6 months for premium books. Includes hundreds of books about computer programming, data science, software architecture, and more.
$7.99/ month
A Light Reader Membership includes access to all of Leanpub's books which are free with membership, and includes 1 book credit every 2 months for premium books. The book credits are delivered every other monthly payment, starting with the second payment.
$17.99/ month
A Standard Reader Membership includes access to all of Leanpub's books which are free with membership, and includes 1 book credit every month for premium books. The book credits are delivered every monthly payment.
$27.99/ month
Get access to hundreds of books that are free with your Reader Membership, and get credits to use toward purchasing the rest.
Get free access to about 2000 books on Leanpub that are free with membership. This includes hundreds of books about computer programming, data science, software architecture, and more.
This is the FAQ for Leanpub Reader Memberships. If you're looking to learn more about Author Memberships, please see the Author Memberships page.
If you can't find what you're looking for below, chances are the answer is in our amazing Help Center which has hundreds of carefully-written articles and a number of lovingly-created videos answering the questions we've been asked over the years. Or, email our support team and one of us will get back to you.
No! You can always buy Leanpub books or courses with money, without having a Reader Membership.
A Reader Membership is a paid subscription that gives you access to about 2,000 Free With Membership books, plus book credits you can use to purchase Leanpub books. Membership is optional: you can read and buy books on Leanpub without subscribing.
Course credits are available through Learner Memberships. A Learner Membership includes both book credits and course credits. If you want course credits, please see our Learner Memberships page. Reader Memberships focus on books only.
No. Every Leanpub user can read and buy books, but a Reader Membership is always a paid subscription that provides additional reading benefits. If you have not paid for a Reader Membership, you simply do not have one.
All Reader Memberships give you access to about 2000 books that are Free With Membership. Our Mini, Light, and Standard Reader Memberships all come with book credits, with higher levels including more credits per month. All Reader Memberships allow you to purchase additional book credits. Our Legacy Reader Membership (no longer offered for sale) does not include credits, only access to the Free With Membership books.
No. You need a Reader Membership to buy book credits. You can always buy Leanpub books with money without having a Reader Membership. Any Reader Membership — including the currently offered Mini, Light, and Standard plans, as well as the no-longer-offered Legacy Reader Membership — lets you purchase additional book credits.
Every Leanpub user can have multiple memberships: a Reader Membership, a Learner Membership, and an Author Membership. This FAQ explains the Reader Memberships. A Reader Membership affects your features as a Leanpub reader (books), a Learner Membership gives you book and course credits, and an Author Membership affects your features as a Leanpub author.
A Reader Membership gives you access to about 2000 books which are Free With Membership, along with book credits you can use to buy Leanpub books. Your membership also helps support Leanpub authors through our Royalty Pool, and it gives you the convenience of buying books instantly with credits. Different Reader Membership levels include different amounts of book credits.
There are about 2000 books which are Free With Membership. You can search them by going to the Store in the top menu, choosing the Books submenu, and changing the filter from Bestsellers Last Week to Free With Membership.
Yes! You can search them by going to the Store in the top menu, choosing the Books submenu, and changing the filter from Bestsellers Last Week to Free For Everyone. Any reader, including those without a Reader Membership, can read these books for free.
Most of the cost of the paid Reader Memberships goes toward paying for the book credits that you get. Leanpub authors earn excellent royalties from those credit purchases, as you'll see below. We also pay into a Royalty Pool to support the authors of the books you get which are Free With Membership.
A Reader Membership gives you book credits, typically at a discount to their a la carte price. These credits can be used toward buying any book on Leanpub. It's easier to pay with credits than with money: just click a button! You also get free access to about 2000 books which are Free With Membership. Your paid Reader Membership helps support Leanpub authors through the Royalty Pool. Finally, your paid Reader Membership helps us build a better Leanpub for our authors and our readers!
One or more book credits can be used to purchase ANY Leanpub book. Every Leanpub book has a price in credits listed on its store page. When you use credits to purchase a book, you do not pay anything extra. (You pay any taxes on credits when buying the credits themselves.) Most Leanpub books cost just 1 book credit.
You get book credits when your Reader Membership subscription renews, either monthly or annually. You can also buy additional book credits at any time from the Buy Credits page.
We have different levels of paid Reader Memberships that come with different numbers of book credits. However, if you need extra credits, you can buy them easily on the Buy Credits page. This way, you can get the credits you need without changing your membership level, and have the convenience of shopping with credits instead of money.
Yes, as long as you have a Reader Membership! Just add the credits to the shopping cart on the Buy Credits page, and at checkout choose to pay with your Leanpub royalties, credit card or PayPal.
No. Since all Reader Memberships we currently sell include credits, we no longer offer a Lifetime option for any of these Reader Memberships. So, because of this, you cannot use royalties. Making royalty purchases work for subscription payments would be too complex to justify doing.
We used to sell just one type of Reader Membership. We are now calling this the Legacy Reader Membership. The Legacy Reader Membership used to cost $4.99 per month, $19 per year, or $99 lifetime. The Legacy Reader Membership provided free access to about 2000 books which are Free With Membership, and did not come with any credits for premium books. The Legacy Reader Membership is no longer available for sale.
If you currently have a Legacy Reader Membership, nothing changes. Your price does not increase, and the membership benefits do not change. This is true if you have a Monthly, Annual or Lifetime Legacy Reader Membership. Your membership continues to give you free access to about 2000 books which are Free With Membership.
If you upgrade from a Monthly or Annual Legacy Reader Membership, you cannot downgrade back to the Legacy Reader Membership. If you upgrade from a Lifetime Legacy Reader Membership, you will automatically downgrade back to the Lifetime Legacy Reader Membership if your upgraded Reader Membership expires or if you cancel it.
Credit pricing is based on each book's maximum discounted price. Divide by $25 and round up. So, a $19 book costs 1 credit, and a $39 book costs 2 credits. Most books cost just 1 credit. Authors can opt out of credit pricing if they choose.
For credit card, PayPal or royalty purchases, we pay 80% royalties on books priced at $7.99 and up. Below $7.99, we pay 80% minus 50 cents. So, Leanpub authors earn $3.50 from a $5 sale, $8 from a $10 sale, $16 from a $20 sale, and $24 from a $30 sale. Leanpub was founded by authors, and exists to serve our authors.
Book credits are taxed like Leanpub ebooks. For our EU and UK customers, this means that if your country has a discounted rate for ebooks, then the book credits will have this same discounted rate. This is correct because a book credit can only be used to purchase a Leanpub ebook, so it is a single-purpose voucher whose VAT rate can be calculated at the time of purchase. For example, in the UK, ebooks are taxed at 0% VAT.
Yes! When you use book credits to purchase a book, the author still earns great royalties. Typically the author earns the same amount of royalties as a minimum nonzero price purchase with a credit card or PayPal. So, you continue to provide excellent support to Leanpub authors when you use book credits to make a purchase.
The short answer is that the author typically earns the same royalties they would earn on a minimum nonzero price purchase. The longer answer is that the royalty rate is determined by comparing the credit cash price to the minimum nonzero price, as explained in the questions below.
The credit cash price is the cash equivalent of the credit price. To calculate it, the credit price is multiplied by $25 per book credit, regardless of the actual purchase cost. For example, if a book has a 2 book credit price, the credit cash price is $50 (2 x $25). The credit cash price is then compared to the minimum nonzero price to determine author royalties.
The minimum nonzero price is set by the author, and is the minimum non-free price that a reader can pay for a book. Leanpub books can also be available for free, either Free With Membership or Free For Everyone. However, even in these cases, there is also a minimum non-free price which the author sets. The minimum nonzero price affects how author royalties work for purchases using credits.
If the credit cash price is lower than the minimum nonzero price, the author earns 80% royalties on the credit cash price. So, the author earns $20 per book credit used (80% of $25). For example, if a book has a $29 minimum nonzero price and a 1 book credit price, the author earns $20 when a reader purchases with 1 book credit. This is the ideal scenario: the reader gets a slight discount, and the author still earns excellent royalties!
If the credit cash price is greater than or equal to the minimum nonzero price, the purchase is treated as a minimum nonzero price purchase. For example, if a book has a $19 minimum nonzero price and a 1 book credit price, the author earns $15.20 (80% of $19). Or, if a book has a $39 minimum nonzero price and a 2 book credit price, the author earns $31.20 (80% of $39). In all cases, the author earns the same royalties as on a minimum nonzero price purchase.
Click on the Help menu above to go to our amazing Help Center. We put way more thought and effort into it than you would typically expect. Check it out, and if you can't find the answer, email us at hello@leanpub.com!
Save money, support authors and support Leanpub with your Reader Membership!
Sign up nowWe're authors too, and we built Leanpub to be the platform we would love to use. It turns out, we weren't alone...
As an academic, I like Leanpub because it lets me write and get my ideas out there quickly. Leanpub is simply the best place for publishing my books.
Leanpub's book-creation tools allowed me to focus on creating the types of books I wanted to write instead of worrying how to create my own book publishing toolchain. I have never regretted using Leanpub to publish my ebooks.
Leanpub takes the pain out of publishing. They provide the tools, you provide the books and then magic happens.
I love using Leanpub because I can write my book using simple Markdown notation. Leanpub let's me focus on my content and they handle the rest.
Leanpub is a game changer for independent authors, removing the hassles associated with formatting, book production, and electronic sales, freeing up the time to do what we do best: write.
Leanpub helped me achieve my goal of publishing a book. Its simple, easy to use interface got my book up and making money within weeks, I love Leanpub!
Leanpub helped me gauge interest in my book, get payments early on when it was only a few chapters, and has got me a bunch of sales just from people browsing around the site.
Leanpub helps me see my books as I write them. Even better, I can find readers early, to read my books and offer suggestions. I can pivot, if I see the need.
Leanpub made it simple for me to run with my book idea and build my reputation in the Ruby community. I went from first draft to first sale in days, not months or years.
Four years ago, I joined Leanpub to just give it a try. Today, over 28,000 book sales later, I cannot help but say that I'm the biggest Leanpub fan on this planet!
Leanpub makes publishing your own book super easy. The fact that you can release updates continually helps with the mindset of getting a minimum version out ASAP and then iterating to improve.
I earn more royalties from my books on Leanpub than I do with well established publishers or through Amazon (which I publish on thanks to Leanpub's mobi conversion).
Leanpub allows me focus on content, takes care everything else and offers an amazing author royalty. It’s a fantastic platform for writing and publishing books.
I love that Leanpub makes writing and publishing a beautiful book so simple. I no longer spin my wheels with layouts and formats - Leanpub gets out of the way when it's time to write, and then automates everything when it's time to publish.
With Leanpub, the first person who purchased my book for $9.99 almost two years ago (and only received a preface, and two short intro chapters) has had access to almost every bit of knowledge I've gained in those two years, and *that's* the value.
Simple and lean, forces me to focus on writing and marketing, and pays excellent royalties.
Leanpub forces you to focus on writing and gives you immediate feedback. Allowing Leanpub to take care of the curation and delivery helped me focus on shipping my book.
While most eBook exporter apps today can generate PDF files and many support ePub, there's one tool we recommend above all after trying 8 of the most popular: Leanpub.
