AI cache

The ai-cache block keeps model responses so a repeated request is answered from Postgres instead of the provider. The key is a SHA-256 of whatever the application decides makes two requests equal, usually the model, the prompt and the settings. The AI SDK cache middleware builds the key and replays a cached stream; this page covers the block itself.

better-supabase sql add ai-cache

Entries hold prompts and answers, so only the service role reads or writes them: no member sees another member's cached answer through the Data API. Create the block with a service transport.

ServerCopy Anchor Link

import "server-only";

import {
  cacheKey,
  createAiCache,
  rpcTransport,
} from "better-supabase/blocks/ai-cache";

export const aiCache = createAiCache({
  transport: rpcTransport(bs.admin().$client, { schema: "api" }),
  schema: "api",
});

const key = await cacheKey({
  model: "openai/gpt-5-mini",
  prompt,
  temperature: 0,
});
const cached = await aiCache.get<string>(key).orThrow();
if (cached === undefined) {
  const answer = await summarize(prompt);
  await aiCache
    .set(key, answer, {
      ttl: 3600,
      organizationId,
      kind: "generate",
      model: "openai/gpt-5-mini",
    })
    .orThrow();
}

cacheKey(parts) sorts object keys before hashing, so { a, b } and { b, a } give the same key. get counts a hit and returns undefined for a missing or expired entry. clear({ organizationId }) or clear({ model }) deletes a tenant's or a model's entries, and the tenant lifecycle deletes a tenant's entries with its other rows.

Purge jobCopy Anchor Link

Expired entries are never returned, but they stay in the table until the purge job deletes them. Schedule it hourly through the jobs block:

handlers: {
  ai_cache_purge: aiCache.purgeJob({ batch: 5000 });
}

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