23 lines
1.2 KiB
Markdown
23 lines
1.2 KiB
Markdown
---
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id: runtime-cache-reusable-data
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title: Runtime Cache for reusable server data
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status: active
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candidateKinds: ["slow_route", "external_api_slow"]
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frameworks: ["*"]
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priority: 84
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citations: ["https://vercel.com/docs/caching/runtime-cache", "https://vercel.com/docs/functions/functions-api-reference/vercel-functions-package"]
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maxBriefChars: 850
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---
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## Investigation Brief
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Runtime Cache is only useful when the same server-side result is reused across requests. Treat it as a measured alternative when CDN response caching is unsafe or incomplete.
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## Evidence To Check
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Use p75/p95 latency, call count, caller routes, and transfer bytes. In source, identify database queries, external API calls, or expensive computations that return the same result for many viewers.
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## Do Not Recommend When
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Skip per-user data, mutations, secrets, one-off requests, or unknown freshness. Skip Runtime Cache when CDN caching solves the route. For Next with Cache Components, check `use cache: remote` first; use Runtime Cache only as a justified fallback.
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## Verification
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Name the reusable data, observed route or hostname pressure, required freshness window, and the exact call site to wrap.
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