# Back end

Concept · [Technical basics](https://ecosystem.samcarlton.com/technical)

Also called: backend, back-end, server side, business logic

The part of an app that runs out of sight on a [server](https://ecosystem.samcarlton.com/server). It saves information, [checks](https://ecosystem.samcarlton.com/automated-check) who is allowed to do what and does the work the [front end](https://ecosystem.samcarlton.com/front-end) asks for. Any app that has accounts or saves information needs one, including apps made with [no-code](https://ecosystem.samcarlton.com/no-code) or AI tools.

**For example:** You tap 'Place order'. The [front end](https://ecosystem.samcarlton.com/front-end) shows the button. The back end [checks](https://ecosystem.samcarlton.com/automated-check) the payment, saves the order to the [database](https://ecosystem.samcarlton.com/database) and sends the receipt.

## Connects to (28)

- [Front end](https://ecosystem.samcarlton.com/front-end): The part of an app or website that people see and tap, running in their browser or on their phone.
- [Database](https://ecosystem.samcarlton.com/database): Organized storage for your app's information, such as users, orders and messages, so it can be saved and looked up later.
- [API](https://ecosystem.samcarlton.com/terms/api): Application programming interface.
- [API key](https://ecosystem.samcarlton.com/api-key): A secret code that identifies your app to another service so that service will answer its API requests.
- [Authentication](https://ecosystem.samcarlton.com/authentication): Checking that a person is who they say they are, usually with a login.
- [Tech stack](https://ecosystem.samcarlton.com/tech-stack): The set of programming languages and tools a product is built with.
- [Server](https://ecosystem.samcarlton.com/server): A computer that stays on and connected to the internet so it can run your app and answer requests from people's phones and browsers.
- [Static site](https://ecosystem.samcarlton.com/static-site): A website made of fixed pages that look the same for every visitor.
- [No-code](https://ecosystem.samcarlton.com/no-code): Tools that let you build an app or site by arranging visual blocks or describing what you want, instead of writing code.
- [Supabase](https://ecosystem.samcarlton.com/supabase): An open source back end platform built on the Postgres database.
- [OKC Web Devs](https://ecosystem.samcarlton.com/okc-web-devs): An Oklahoma City programming user group in the Techlahoma network.
- [REST API](https://ecosystem.samcarlton.com/rest-api): A common style of API where each kind of data lives at its own web address and software reads or changes it with standard web requests…
- [ORM](https://ecosystem.samcarlton.com/orm): Object-relational mapping.
- [API contract](https://ecosystem.samcarlton.com/api-contract): An agreement on exactly what requests an API accepts and what responses it returns.
- [Server-side rendering](https://ecosystem.samcarlton.com/server-side-rendering): Building a web page's HTML on the server before sending it, instead of in the visitor's browser.
- [Headless commerce](https://ecosystem.samcarlton.com/headless-commerce): Running a store's products, cart and checkout on one system while building the shopping screens separately.
- [Vertical slice](https://ecosystem.samcarlton.com/vertical-slice): A small piece of a product built all the way through, from screen to database to deployment, so it actually works for a user, rather than…
- [Python](https://ecosystem.samcarlton.com/python): A programming language known for being easy to read.
- [PHP](https://ecosystem.samcarlton.com/php): A programming language for building websites on the server.
- [Rust](https://ecosystem.samcarlton.com/rust): A programming language for fast, reliable software that prevents many memory bugs before the program runs.
- [C#](https://ecosystem.samcarlton.com/csharp): A programming language made by Microsoft and used with .NET for business software, Windows apps, web services and games made with Unity.
- [Next.js](https://ecosystem.samcarlton.com/next-js): A framework built on React for making full websites and web apps, including pages rendered on the server.
- [Drools](https://ecosystem.samcarlton.com/drools): An open-source business rules engine written in Java, now part of the Apache KIE project.
- [Elasticsearch](https://ecosystem.samcarlton.com/elasticsearch): Software for fast searching across large amounts of text and data, from Elastic.
- [Firebase](https://ecosystem.samcarlton.com/firebase): Google's platform for building app back ends, with a database, login, file storage and hosting as managed services.
- [Convex](https://ecosystem.samcarlton.com/convex): A hosted back end for web apps that combines a database with server functions written in TypeScript, and pushes changes to the app as they…
- [Directus](https://ecosystem.samcarlton.com/directus): An open-source tool that puts an admin app and an API on top of a SQL database, so non-developers can manage the content.
- [Oklahoma City Java User Group](https://ecosystem.samcarlton.com/okc-java-user-group): A free user group that promotes Java and related topics in the Oklahoma City area, with talks on programming topics.

Map view: https://ecosystem.samcarlton.com/back-end