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| index: 1 |
| layout: guide |
| nav: Intro |
| title: Introduction to PouchDB |
| sidebar: guides_nav.html |
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| Welcome to the PouchDB guide! Consider this your starting point for anything and everything related to the world of PouchDB and CouchDB. |
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| For a quicker TodoMVC-based tutorial, you can also check out the ["Getting Started" guide](/getting-started.html). |
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| Feel free to skip ahead using the sidebar at any time. |
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| What is PouchDB? |
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| **PouchDB** is a JavaScript implementation of [CouchDB](http://couchdb.com). Its goal is to emulate the CouchDB API with near-perfect fidelity, while running in the browser or in Node.js. |
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| What is CouchDB? |
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| **CouchDB** is a NoSQL database created in 2005 by Damien Katz, and now maintained by the Apache Software Foundation. If you are a JavaScript developer, you probably use CouchDB every day, because it's the core technology that powers [npm](https://www.npmjs.org/). |
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| Couchbase, CouchDB, Couch-wha? |
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| Today there are two major database companies that |
| can trace their lineage back to CouchDB: [**Couchbase**](http://couchbase.com) and [**Cloudant**](http://cloudant.com). Both of them are separate products compared to CouchDB. |
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| However, all three of these databases share the same **CouchDB sync protocol**. This means that PouchDB can sync with either one of them, and you can always swap out one database for another. You're never locked in. |
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| In a sense, these databases are like competing phone companies, and the CouchDB sync protocol is the underlying telephony infrastructure. |
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| CouchDB's one-two punch: HTTP and sync |
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| With so many SQL and NoSQL databases out there – MongoDB, PostgreSQL, MySQL, etc. – you may wonder why we chose to implement CouchDB instead of the others. |
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| We have two very good answers to that question: **HTTP** and **sync**. |
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| HTTP: the little protocol that could |
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| When working with databases, we're often accustomed to writing some kind of conversion layer between the database and our client-side applications. This means, however, that we are just translating database queries into RESTful HTTP calls, over and over. For every app we write. |
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| CouchDB throws this out the window by daring us to talk to the database directly, from our client-side apps. And it does so by using HTTP as its primary means of communication. No special protocol, no special drivers: just REST and HTTP. You can communicate with CouchDB entirely through your browser, `curl`, or a REST client like [Postman](https://chrome.google.com/webstore/detail/postman-rest-client/fdmmgilgnpjigdojojpjoooidkmcomcm). |
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| In this way, CouchDB truly is a "database for the web." |
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| Sync: CouchDB's killer feature |
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| Another unique feature of CouchDB is that it was designed from the bottom-up to enable easy synchronization between different databases. |
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| For example, if you are worried about latency in your client-side applications, you can simply set up one CouchDB in Europe, another in North America, and another in Asia. After enabling continuous two-way replication between these databases, your clients can simply talk to whichever one is closer. |
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| PouchDB takes this one step further by putting the database inside your browser. |
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| Next |
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| Now that you understand the basics of the PouchDB/CouchDB universe, let's set up CouchDB! |
