Keyword search

Last updated Oct 16, 2026 Enable keyword search to match chunks that contain your query terms exactly. For an overview of search modes, refer to Search modes.

Enable keyword search

Set index_method.keyword to true when creating or updating an instance. You can use keyword search on its own or alongside vector search for hybrid search.

At least one of vector or keyword must be true. Changing index_method triggers a full reindex of your content.

The keyword field defaults to true.

const instance = await env.AI_SEARCH.create({
    id: "my-instance",
    index_method: {
        vector: false,
        keyword: true,
    },
});

Keyword tokenizer

The keyword_tokenizer field (inside indexing_options) controls how text is split into tokens. Changing this triggers a full reindex.

Japanese, Chinese, and Korean content

The porter tokenizer splits text on spaces and punctuation, so it does not work well for Japanese, Chinese, or Korean. Japanese and Chinese do not separate words with spaces, and Korean attaches particles to words. Keyword search with porter may return no results for queries in these languages.

If your content is in Japanese, Chinese, or Korean, use the trigram tokenizer. With trigram, keyword search matches these queries, including full natural-language questions, against overlapping three-character sequences in your content. Words shorter than three characters cannot be matched on their own.

Keyword match mode

The keyword_match_mode field (inside retrieval_options) controls how multiple query terms are combined.

You can override keyword_match_mode per request:

const instance = env.AI_SEARCH.get("my-instance");

const results = await instance.search({
    messages: [{ role: "user", content: "What is Cloudflare?" }],
    ai_search_options: {
        retrieval: {
            keyword_match_mode: "or",
        },
    },
});

Limits

Instances with keyword search enabled support up to 500,000 files per instance on the Workers Paid tier, compared to 1,000,000 for vector-only instances. Refer to Limits and pricing for the full list of limits.

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description: Define built-in and custom metadata attributes on indexed documents. title: Metadata attributes image: https://developers.cloudflare.com/ai-search/configuration/indexing/metadata/og.png?v=008494fda3bce36d

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