# Web data API

A web data API is an application programming interface (API) that acts as a standardized bridge between software systems across the web. You send a request, and you get structured data back without needing to know how the other system stores or builds that data.

A web data API is an interface that lets software applications request and exchange data with other systems over the internet, usually through HTTP requests and responses in formats like JSON or XML.

## What is a web data API?

A web data API is an application programming interface (API) that acts as a standardized bridge between software systems across the web. You send a request, and you get structured data back without needing to know how the other system stores or builds that data.

APIs now carry most of the traffic online, so nearly every modern app leans on them to move data. Cloudflare reports that APIs make up [over half of internet traffic](https://www.cloudflare.com/2024-api-security-management-report/), at 57%.

At Parallel, we build web data APIs purpose-built for AI agents. Our [web search API](https://parallel.ai/articles/what-is-a-web-search-api) returns token-efficient markdown of dense page excerpts that large language models (LLMs) can read directly.

## Key characteristics

- **Requests over HTTP:** A client sends a Hypertext Transfer Protocol (HTTP) request to an endpoint, and the server returns data or an error.
- **Standard data formats:** Responses come back in machine-readable formats, most often JavaScript Object Notation (JSON) or Extensible Markup Language (XML).
- **Architectural styles:** Most web data APIs follow Representational State Transfer (REST), which dominates at 93% per Postman's [2025 State of the API report](https://www.postman.com/state-of-api/2025/). Others use GraphQL or WebSocket.
- **Access control with keys:** An API key authenticates each request and lets the provider secure and track usage.
- **Abstraction:** The API exposes only the data and actions the provider chooses, and it hides the underlying database.

We measure quality in the open. Parallel reaches 91% accuracy on the SimpleQA benchmark and leads fast web search providers on BrowseComp.

![Parallel web search API accuracy benchmarks](https://cdn.sanity.io/images/5hzduz3y/production/50aa4294bd61a539e76907fcb537c7db5266ebd7-1920x1080.png)

_Parallel's __[published accuracy benchmarks](https://parallel.ai/benchmarks)__ compare web search APIs on accuracy and latency._

## Example

A travel booking company uses airline web data APIs to request live fares from several carriers, and its site shows the results in one view. Each carrier keeps its own pricing system, yet the company reads every fare through the same request pattern.

An AI agent calls Parallel's [Search API](https://parallel.ai/products/search) to find relevant pages for a research question. It then uses the [Extract API](https://parallel.ai/products/extract) to turn any public URL into clean markdown in a single call.

## Related terms

- [web scraping](https://parallel.ai/articles/what-is-web-scraping): Pulling data straight from a page's HTML rather than through a structured API.
- [semantic search](https://parallel.ai/articles/what-is-semantic-search): Retrieving results by meaning and intent instead of exact keyword matches.
- [deep research APIs](https://parallel.ai/articles/what-is-deep-research): Running multi-step research across many sources to return cited, structured findings.

## FAQ

**What is the difference between a web API and a data API?**

A web API is any interface that works over the internet using web protocols. A data API is a web API focused on accessing and exchanging data between systems.

**What format does a web data API return?**

Most return data in JSON or XML, machine-readable formats that any programming language can parse.

**Do web data APIs have real business value?**

Yes, they do. In Postman's 2025 State of the API report, 65% of organizations now generate revenue from their APIs.