What Is Claude? Anthropic's AI Model, Explained

Claude is a family of AI language models built by Anthropic, an AI safety company founded in 2021 by former OpenAI researchers. Claude takes text (and in some interfaces, images, files, or PDFs) as input and generates text as output — it can answer questions, write and debug code, summarize documents, draft content, and act as a reasoning engine inside larger applications.

If you're searching "what is the claude," you're probably trying to understand whether it's a chatbot, a company, a product name, or something else entirely. The short answer: Claude is the name of Anthropic's AI model line, and also the name of the chat product (web, desktop, and mobile apps) built on top of those models. Under the hood, developers interact with the same models through an API, which is what powers most third-party tools, coding assistants, and business integrations that mention Claude.

Claude the Model vs. Claude the App

It helps to separate two things that share a name:

• Claude (the model): a large language model trained by Anthropic. There are multiple versions and sizes, released over time, each with different capabilities, context window sizes, and pricing.
• Claude (the app): the consumer-facing chat interface at claude.ai, plus desktop and mobile apps, where you type messages and get responses in a conversational UI.

Most people's first exposure to Claude is the chat app. But the model itself is also available as an API, which is how it gets embedded into IDEs, customer support tools, internal company dashboards, and SaaS products — including tools that don't advertise "Claude" anywhere in their branding.

What Claude Is Actually Good At

Claude is a general-purpose language model, but a few use cases stand out in practice:

• Coding: writing functions, refactoring, explaining unfamiliar codebases, and reviewing pull requests.
• Long-document work: summarizing contracts, research papers, or transcripts thanks to a large context window.
• Structured output and tool use: recent Claude models can call external functions/tools, which lets developers build agents that fetch data, run calculations, or trigger actions instead of just producing text.
• Writing and editing: drafting emails, marketing copy, documentation, and rewriting text in a specific tone.

Where it tends to fall short of expectations: real-time information (it doesn't browse the web unless the app or integration explicitly adds that capability), perfect factual accuracy on obscure topics, and anything requiring guaranteed determinism — outputs can vary between runs even with the same prompt.

How People Actually Access Claude

There are three common paths, and they solve different problems:

1. Chat app (claude.ai): best for individual, conversational use — asking questions, brainstorming, one-off writing tasks. No coding required.
2. Direct API from Anthropic: best for teams building a product feature or internal tool who want full control over billing, rate limits, and infrastructure, and who are comfortable managing API keys, usage monitoring, and Anthropic's own account setup.
3. A hosted API layer on top of Claude: best for teams that already have Claude access (through a subscription or existing account) and want to expose it as a clean HTTPS API for their own applications, without building separate billing and key-management infrastructure from scratch.

This third option is where a service like SubToAPI fits. It turns your existing Claude access into application-level API keys (sub_live_...) with streaming support, tool use, usage metadata, and team seat management in one dashboard — useful if you want to give multiple developers or services their own scoped keys without sharing a single account's credentials.

A Minimal Example

Once you have an API key, calling Claude through a compatible endpoint looks like a standard HTTPS request. Here's what a basic message call looks like using SubToAPI's endpoint:

curl https://api.subtoapi.app/v1/messages \
  -H "Authorization: Bearer $SUBTOAPI_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "claude-3-7-sonnet",
    "max_tokens": 512,
    "messages": [
      {"role": "user", "content": "Explain what a race condition is in one paragraph."}
    ]
  }'

And the same call in JavaScript:

const res = await fetch("https://api.subtoapi.app/v1/messages", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.SUBTOAPI_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    model: "claude-3-7-sonnet",
    max_tokens: 512,
    messages: [
      { role: "user", content: "Explain what a race condition is in one paragraph." }
    ]
  })
});

const data = await res.json();
console.log(data);

This is the pattern behind most tools that "use Claude" under the hood: a request with a model name, a message list, and a token limit, sent to an HTTPS endpoint. For a full walkthrough of setting this up, see the quickstart guide and the messages reference.

Streaming and Tool Use

Two capabilities matter once you move past simple one-off requests:

• Streaming: instead of waiting for the full response, tokens are sent back as they're generated, which makes chat interfaces feel responsive. Details are in the streaming docs.
• Tool use: Claude can be given a list of functions it's allowed to call (e.g., "search_orders" or "get_weather"), and it decides when to invoke them based on the conversation. This is what powers agent-like behavior. See the tools documentation for the request format.

If you're evaluating whether to build directly against Anthropic's API or through a layer like SubToAPI, the practical difference usually comes down to how much billing, key management, and team access control you want to handle yourself versus get out of the box. Plans start at €9/month for solo use, with Team (€19/seat) and Scale (€49/seat) tiers for larger setups, and a free trial at signup to test it against your own workload. Full pricing is on the pricing page.

Questions

Is Claude the same as ChatGPT? No. Claude is built by Anthropic, ChatGPT by OpenAI. They're separate companies with separate models, though both serve similar use cases — chat, writing, coding assistance.

Do I need to code to use Claude? No. The claude.ai chat app requires no coding. You only need an API setup like SubToAPI's if you're building an application or automation that calls Claude programmatically.

What does "Claude" mean as a name? Anthropic named the model after Claude Shannon, the mathematician often called the father of information theory.