Anak Krakatau — Live Status Dashboard

A public status page for the ongoing Anak Krakatau (Krakatoa) eruption: current alert level, ash advisories, recent activity, and preparedness guidance for people near the volcano.

This app is unofficial. It is not produced by, endorsed by, or affiliated with PVMBG, MAGMA Indonesia, BMKG, or BNPB. It republishes public data those agencies already publish, reformatted for readability, and links back to the originals on every card. For evacuation orders and authoritative guidance, always follow MAGMA Indonesia, BMKG, and BNPB directly — this dashboard says so on every page.

Data sources

All data is scraped server-side from MAGMA Indonesia (PVMBG), the Indonesian government's official volcano-monitoring platform. Nothing is fetched client-side, and nothing is stored beyond the request lifetime.

Source	URL	Used for
MAGMA activity level list	https://magma.esdm.go.id/v1/gunung-api/tingkat-aktivitas	Finds the current signed report for Anak Krakatau
MAGMA signed activity report	linked from the row above, under /v1/gunung-api/laporan/...	Alert level (I–IV), hazard radius, summit coordinates, observation time
MAGMA VONA notices	https://magma.esdm.go.id/v1/vona?code=KRA	Aviation colour code, ash cloud height, ash movement direction
MAGMA eruption timeline	https://magma.esdm.go.id/v1/gunung-api/informasi-letusan/KRA	Recent eruption events shown in the activity timeline

Two adapters were built and deliberately removed during development:

• Darwin VAAC (the ash-advisory source in the original design spec) — probing it showed the advisory endpoints require authentication or return "does not currently exist" for a live target. MAGMA VONA replaced it; see the plan for the investigation.
• GVP weekly reports and BMKG — cut as unused once MAGMA alone covered every card. tests/fixtures/gvp-weekly.xml stays committed on purpose, as a record of that decision, even though nothing reads it anymore.

Why fixtures are committed

tests/fixtures/*.html are real, saved copies of MAGMA's pages. Tests parse these fixtures instead of the network, so the suite is fast and doesn't hit government servers on every run — servers that, during this eruption, have been intermittently returning 502.

Run bun run fixtures:refresh occasionally to re-download them. A git diff afterwards is the early-warning signal that a source changed its HTML structure: if the parsers still pass against updated fixtures, nothing is wrong; if a fixture's shape moved and a test now fails, that's the adapter that needs attention before it silently breaks in production.

Getting started

bun install
bun run dev

Then open http://localhost:3000 (English) or http://localhost:3000/id (Indonesian).

Commands

Command	Purpose
bun install	Install dependencies
bun run dev	Start the dev server (Turbopack)
bun run build	Production build
bun run start	Run the production build
bun test	Run the test suite (parses committed fixtures, no network)
bun run check	Format + lint, writing fixes
bun run ci:lint	Lint in CI mode (no writes)
bun run typecheck	Generate route types, then tsc --noEmit
bun run fixtures:refresh	Re-download the HTML fixtures tests parse against

If typecheck fails citing files that no longer exist, delete the stale build cache first: rm -rf .next.

Stack

Next.js (App Router) on Bun, TypeScript in strict mode with noUncheckedIndexedAccess, next-intl for English/Indonesian localisation, Tailwind CSS, and MapLibre GL for the ash-direction map. The display timezone is locked to Asia/Jakarta regardless of visitor location, since a hazard report timed to the wrong zone is worse than no time at all.

Design documents

• Design spec
• Implementation plan

Deploying

The app needs no environment variables and no API keys: every source is a public MAGMA page, and the tile provider requires no token.

Vercel Functions are pinned to sin1 (Singapore) in vercel.json. This is not a preference. The server fetches MAGMA in Indonesia, and MAGMA is slow under eruption load — measured at 4.5–8.8s per request from inside Indonesia during the September 2026 eruption, against a 20s timeout. Vercel's default region is iad1 (Washington DC), which would add a trans-Pacific round trip to every one of those requests and push the slow tail past the timeout, so the alert level and ash direction cards would go dark while MAGMA was merely slow. Singapore is the closest region to the Sunda Strait.

Hobby plans may select any single region, so this works without a paid plan.

Two things the Vercel build logs revealed

Direct dependencies are pinned exactly, on purpose. Vercel's build image runs Bun 1.3.14, which cannot read the lockfileVersion: 2 that Bun 1.4 writes. It logs Unknown lockfile version, warns Ignoring lockfile, and resolves every dependency fresh. packageManager: "[email protected]" does not change this. With the lockfile ignored, a caret range would let an untested minor release reach production on its own — so every direct dependency is pinned to an exact version. Transitive packages can still drift; this only removes the largest and most likely source. Once Vercel's image ships Bun 1.4 the lockfile will be honoured again and the pins simply stop mattering.

Builds run in iad1, not sin1. The regions setting places Vercel Functions, not the build. So the build-time prerender fetches MAGMA from Washington DC, where the trans-Pacific round trip on top of MAGMA's own latency often exceeds the 20s timeout — a freshly deployed page can ship showing "Source unavailable". This is not a failure state to fix: the first ISR revalidation runs in sin1 and the page heals itself within a minute. Observed on the first production deploy and confirmed to recover.

Ash areas come from SIGMETs, not from VONA

The map draws the ash-affected area from volcanic-ash SIGMETs (aviationweather.gov/api/data/isigmet, a public NOAA/NWS feed, no key). Each carries the area as coordinates issued by the responsible meteorological watch office — for the Sunda Strait that is BMKG's Jakarta office, so this is an Indonesian authority rather than a foreign estimate.

This replaced a wedge the map used to infer from VONA's prose movement phrase. Two things made the change worth making. A SIGMET states the area rather than implying it, so the shape earns a hard edge. And VONA notices go quiet for days while SIGMETs keep being issued: relying on VONA alone let the page state that no ash cloud was observed while an active BMKG SIGMET said the opposite, which is the worst thing this dashboard can do.

Two properties the UI must keep. A SIGMET describes airspace, not ashfall on the ground, and says so on the card. And SIGMETs expire after a few hours; expired ones are dropped rather than dimmed, because a polygon with no issuing authority behind it is the same lie as a stale timestamp.