SDK

in English: software development kit

advancedwidespread

An SDK is a package of pre-built tools, code snippets, and documentation that enables developers to quickly build applications for a specific platform or service.

In plain terms

Imagine buying flat-pack furniture. The box contains pre-cut panels, screws, an Allen key, and assembly instructions. An SDK is a similar package for programmers: a company bundles everything needed for others to build on their system. The difference is that instead of a single, pre-designed piece of furniture, the developer assembles their own program from the provided components.

Without this, the developer would have to write many things themselves: how to connect to the service, how to authenticate, and how to handle errors. The SDK provides ready, tested building blocks for these, so the developer mainly has to focus on their own idea.

In the AI world, you hear about it often because major model developers make their models available via API and provide an SDK so developers can use them with a few lines of code. Special agent SDKs have also emerged: with these, you can build an agent that not only answers but uses tools and works independently in multiple steps.

How it works

The platform or service provider assembles the package: it includes ready-made code libraries, utilities, sample examples, and documentation.
The developer downloads and installs the SDK on their own machine, typically with a single command, in a version suitable for the chosen programming language.
In their own program, they call the SDK's ready-made functions, such as 'send this question to the model'. A few lines of code are enough for this.
The SDK performs the small tasks in the background: it establishes the connection, identifies the program with the developer's key at the service, translates the request into the service's language, and handles errors.
When the service changes, its owner releases a new SDK version, and the developer updates so their program continues to work.

An everyday example

When you pay with a card or your phone in an online store app, the payment window is usually not written by the store's programmers. They integrated the payment provider's SDK, which is why payments look and work the same across many different applications.

Who is affected

developerEveryday tool: it is how a developer plugs AI models, payments or maps into their program, or builds their own agent. → Code

entrepreneur, executiveA good SDK can shorten development by weeks, but it ties the company more strongly to a specific provider.

everyoneMost apps running on your phone are built on other people's SDKs, and some of these collect data about you.

A common misconception

MythThe SDK and the API are the same, just with different names.

In realityThe API itself is the gateway through which two programs communicate. The SDK is the toolbox that facilitates using the gateway and is mostly built on the API.

Limits and risks

The SDK is tied to its provider: if you switch providers, you must partially rewrite the code built on it.
The embedded SDK is foreign code in your own program, so its bugs and security vulnerabilities become yours.
Some SDKs, especially those for advertising and analytics, can collect data without the user's knowledge, posing a data protection risk.
Older versions become obsolete over time, so updating represents regular maintenance work.

Similar, but not the same

API – The API is the service's connection point and rule system, while the SDK is the ready-made toolset provided for it.
code library – A library is a code collection for a specific task; an SDK is broader, including libraries, tools, examples, and documentation.
Keretrendszer – The framework dictates the entire structure of the program, while the SDK only provides tools that you use where you need them.

Related concepts

Broader

Software development, Developer tools

Narrower

Agent SDK

On the edge

API, code library, Keretrendszer, Open source, MCP (Model Context Protocol), coding agent

A brief history

Development kits grew out of the practice of platform manufacturers: operating system and game console manufacturers already helped external programmers in the 1980s and 1990s to write software for their systems. The term became widely known with smartphones when Apple released the iPhone SDK in 2008 and the App Store opened.

Where things stand

The SDK has been a basic tool of software development for decades. As of late 2026, every major AI company offers an SDK for its models, and agent SDKs for building agents are also spreading rapidly.

Status: 2026 November

In the news

Appears in 5 Agent Age stories; the curve shows weekly occurrence in the news magazine.

Docker, Pydantic AI and Google ship tools to run AI agents in isolated environmentsOct 21, 2026 · Code
Silicon Labs brings AI to embedded development; Google Cloud releases MCP Toolbox Java SDK 1.0Oct 6, 2026 · Code
Agent platform race: Cursor and OpenAI coordinators, Atlassian, AWS, Cloudflare, Moonshot, AntigravitySep 21, 2026 · Code
OpenAI positions the open Codex agent harness as a platformAug 20, 2026 · Code
Developer platform updates: Copilot web controls, Java SDK, JetBrains memory and ACPAug 10, 2026 · Code

Also known as

SDK · software development kit · software development kit · software development kit · developer kit · development kit · devkit · agent SDK

This entry was machine-edited and has undergone machine expert review; the “In the news” section updates automatically from Agent Age stories.