docs(self-hosted): static Astro serving replaces Next.js + cache proxy

[devin-ai-integration]

Summary

The self-hosted docs container no longer runs a Next.js server behind a caching proxy: the docs site is pre-rendered as a static build inside the image and served off disk. That makes the self-hosted docs pages describing cache warmup, cache-proxy tuning, and Node heap sizing wrong, and it means the server-tuning environment variables customers may have in their Dockerfiles and Kubernetes manifests no longer do anything. This PR deletes that stale configuration surface, corrects the base-path and health-check descriptions to the static model, and adds a changelog entry telling customers which variables to remove. Serving is faster and more predictable, and self-hosted configuration is smaller.

Implements docs for: feat(self-hosted): serve self-hosted docs with Astro static output (fern-api/fern-platform#13991)

Changes

fern/products/docs/pages/self-hosted/self-hosted-set-up.mdx

• Removed the Cache warmup and Cache proxy sections and the NODE_MEMORY_LIMIT row. Verified gone from the container in the PR diff and absent from servers/self-hosted/ on main: NODE_MEMORY_LIMIT, WARMUP, WARMUP_TIMEOUT, CACHE_MAX_ENTRIES, CACHE_MAX_ENTRY_SIZE, CACHE_DEFAULT_TTL, CACHE_CDN_TTL, CACHE_DISABLED, CACHE_PROXY_DEBUG.
• Kept CUSTOM_DOMAIN, FERN_LOG_LEVEL, NEXT_PUBLIC_BASE_PATH, CORS_PROXY_ALLOWED_DOMAINS, and ENABLE_JAEGER — all still read by the container (scripts/run.sh, scripts/static-server/config.ts).
• Rewrote the runtime base-path tab: the base path is compiled into every URL of the static site, so a runtime value that differs from the build-time one re-renders the site at startup, which requires the builder to still be in the image (FERN_KEEP_BUILD_TOOLS=1 or runtime generation) and remains incompatible with readOnlyRootFilesystem: true (scripts/run.sh static-site block).

fern/products/docs/pages/self-hosted/health-check-endpoints.mdx

• "Next.js docs server (via root endpoint)" → static docs server; readiness now probes the static server's /__health plus the docs landing page (scripts/readiness.sh, scripts/liveness.sh). Ports 3000/8081 and the /liveness, /readiness, /health contracts are unchanged.

fern/products/docs/pages/self-hosted/self-hosted-static-export.mdx

• Preview workflow no longer sets -e WARMUP=true, and the readiness gate uses the documented http://localhost:8081/readiness probe instead of the removed admin-token-gated /__cache/stats endpoint (scripts/export.sh now uses /__admin/export and /tmp/.fern-admin-token; /scripts/export.sh and the export tarball path are unchanged).

fern/products/docs/pages/changelog/2026-08-23.mdx — new entry listing the removed variables.

Note for reviewers

The On-page feedback section on the setup page documents [fern-docs-feedback] stdout logs. That handler lives in the Next.js bundle route (packages/fern-docs/bundle/.../api/fern-docs/feedback-log/route.ts) and I found no equivalent in the self-hosted static server, but PR #13991 doesn't touch it, so I left the section alone rather than guess. Worth confirming it still works in the static container.

Validation

• pre-commit run --files <changed>: passes (remaining Vale warnings are on pre-existing lines).
• cd fern && npx fern-api@5.59.0 check --warnings: 0 errors.

Link to Devin session: https://app.devin.ai/sessions/b7e8e7bf59294e0db199eec091ecf8db

[devin-ai-integration]

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[github-actions]

🌿 Preview your docs: https://fern-preview-devin-1787505289-self-hosted-static-astro.docs.buildwithfern.com/learn

Here are the markdown pages you've updated:

• learn/docs/changelog/2026/8/23
• learn/docs/self-hosted/health-check-endpoints
• learn/docs/self-hosted/set-up
• learn/docs/self-hosted/previews