Claude web search

by AnthropicWeb search

Claude web search is Anthropic's server tool that gives Claude real-time web content while it answers. Claude decides when to search, cites its sources on every answer, and can be capped at a number of searches, held to or kept off given domains, or localized to a city and country. On Opper, opper:web_search on auto uses it when you call Anthropic models on the Messages endpoint, and Opper's own engine everywhere else. Pin "engine": "native" to require it, or pin Jina or SearchBase to keep searches in the EU instead. It runs on 12 routes in the catalogue today.

UseClaude web searchwithin

Add Claude web search on Opper

Set up with agents

Paste this into your coding agent (Claude Code, Cursor, Codex, and more) and it will set up and build with Opper for you.

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Key info

Endpoint

Messages

Region

Provider

Pin it with

"engine": "native"

Index

Brave

Native routes

In your code

1curl https://api.opper.ai/v3/compat/v1/messages \
2  -H "Authorization: Bearer $OPPER_API_KEY" \
3  -H "Content-Type: application/json" \
4  -d '{"model": "anthropic/claude-sonnet-5-5", "max_tokens": 1024,
5       "messages": [{"role": "user", "content": "What changed in the news today?"}],
6       "tools": [{"type": "opper:web_search", "engine": "native"}]}'

Use Claude web search with these models

Step-by-step setup for Claude web search on each of these models through Opper.

Claude Sonnet 5.5 Claude Opus 5.5 Claude Opus 5 Claude Sonnet 5 Claude Fable 5 Claude Opus 4.8 Claude Opus 4.7 Claude Sonnet 4.6 See all 700+ models

More tools on Opper

Jina search

Opper's default search engine for models without their own. Search processing stays in the EU.

Search"engine": "jina"

SearchBase

The Swedish open-source search API, on Europe's own Staan index and hosted in the EU.

Search"engine": "searchbase"

Exa search

Exa's search engine built for AI, on any tool-calling model through one tool entry. US-based.

Search"engine": "exa"