How does an SDK work?

A platform SDK, such as the Android SDK or the Java Development Kit, bundles compilers, debuggers, libraries and documentation for building apps on that platform. A service SDK is smaller: you install a package, create a client with your key and call methods such as client.customers.create() instead of writing HTTP requests by hand.

A good SDK handles the repetitive parts of an API, such as authentication headers, retries, pagination, typed requests and responses, and error handling. Many SDKs are generated from an OpenAPI description, so they match the API’s published contract.

The trade-off is another dependency to keep up to date. When an SDK lags behind its API, or doesn’t exist for your language, you can still call the API directly over HTTP.

Sources

Why does an SDK matter for a website voice agent?

There are two common ways to put a voice agent on a website. You can build the interface and call handling yourself with a vendor’s SDK, which gives you full control and more code to own. Or you can embed a finished widget and manage it through an API, which is quicker to add but fixed in what it shows.

Choose by how much of the experience you need to change, and by who will maintain the code once it’s live.

How Kawl Now works without an SDK

Kawl Now has no SDK, npm package or JavaScript widget API. You add the widget with one script tag, and its button label and colour come from each agent’s saved settings.

To manage the agent from code, call the REST API with any HTTP client and a workspace token, using the OpenAPI 3.1 file at https://app.kawlnow.com/api/openapi as the contract. Tools that read OpenAPI 3.1 can generate a client from that file, though Kawl Now hasn’t published or tested one.

Coding agents can use the remote MCP server instead. It describes its own tools when a client connects, so there’s nothing to install beyond your MCP client’s settings. There are no webhooks either, so poll the API for new conversations.

Common questions

How does an SDK differ from an API?

An API is the interface a service exposes, such as its REST endpoints. An SDK is a kit for using it, usually a client library for one programming language plus documentation and examples. You can always call an API without its SDK.

Do you need an SDK to add a voice agent to a website?

Not always. Some voice agents are built on a vendor’s SDK, while others, including Kawl Now, install with a script tag and need no SDK.