Key takeaways
- An API is a contract: send a request in the agreed form and get a predictable response back.
- Most modern web APIs follow the REST style; SOAP is older, stricter and common in enterprise systems.
- API integration can be native, built on an integration platform or custom-coded.
- MCP often sits on top of APIs, giving AI assistants a standard way to use a tool's actions.
How does an API work
An API works through requests and responses. One application sends a request to an address called an endpoint, saying what it wants, such as "give me this contact" or "create this deal". The other application checks who is asking, does the work and sends back a response with the data or a message saying what went wrong.
Access is controlled. The calling app usually proves who it is with an API key or a sign-in flow such as OAuth, and the provider limits what each key can see and how many requests it can make in a given time.
What is a REST API
A REST API is a web API that treats each kind of record as a resource with its own address and uses standard web methods to act on it. A RESTful API is one that follows this style: GET reads a contact, POST creates one, PATCH or PUT updates it and DELETE removes it.
REST APIs usually exchange data as JSON, which is readable by people and easy for code to handle. Each request carries everything needed to answer it, so servers do not need to remember earlier calls. That simplicity is why most sales and marketing tools publish REST APIs.
What is a SOAP API
A SOAP API is an older style of web API that wraps every message in a strictly defined XML envelope and describes its operations in a formal contract file. It is more rigid and more verbose than REST, but that rigidity suits systems where every field and error must be precisely defined.
You are most likely to meet SOAP when connecting to established enterprise software, such as some finance, ERP or banking systems. New tools rarely choose it.
What does API integration mean for a GTM team
API integration means connecting two tools through their APIs so data or actions flow between them. For a go-to-market team there are three common routes, each with its own trade-off between speed and control.
- A native integration the vendor built and maintains: quick to switch on, limited to what the vendor chose.
- An integration platform that connects many tools with visual workflows: flexible, but another system to own.
- A custom API integration written by a developer: exactly what you need, but someone must maintain it when either API changes.
How is an API different from MCP
An API is how a tool exposes its data and actions, while MCP, the Model Context Protocol, is a standard way for an AI assistant to discover and use those actions. An MCP server for a tool often calls that tool's API underneath, describing each action so an assistant can choose the right one from a plain-language request.
The practical difference is who does the wiring. A custom API integration is built once for one pair of tools; an assistant that speaks MCP can work with any tool that offers an MCP server, within the permissions you grant.
Where Pebbles Ai fits
Common questions
Do I need a developer to use an API?
Not always. Native integrations and integration platforms let non-developers use APIs through settings and visual workflows; a custom API integration usually needs a developer.
What is an API key?
An API key is a secret code that identifies the app making a request, so the provider knows who is calling and what they may access. Treat it like a password and never paste it into shared documents.
Is RESTful the same as REST?
In everyday use, yes. REST is the architectural style, and a RESTful API is one built to follow it.
About this page. Written by the Pebbles Ai team for people who run sales, marketing and growth. Last updated .
