diff --git a/bun.lock b/bun.lock
index f4906c9..fb66c54 100644
--- a/bun.lock
+++ b/bun.lock
@@ -11,6 +11,7 @@
         "@sveltejs/adapter-auto": "^7.0.1",
         "@sveltejs/kit": "^2.57.0",
         "@sveltejs/vite-plugin-svelte": "^7.0.0",
+        "@types/node": "^25.6.2",
         "svelte": "^5.55.2",
         "svelte-check": "^4.4.6",
         "typescript": "^6.0.2",
@@ -89,6 +90,8 @@
 
     "@types/estree": ["@types/estree@1.0.9", "", {}, "sha512-GhdPgy1el4/ImP05X05Uw4cw2/M93BCUmnEvWZNStlCzEKME4Fkk+YpoA5OiHNQmoS7Cafb8Xa3Pya8m1Qrzeg=="],
 
+    "@types/node": ["@types/node@25.6.2", "", { "dependencies": { "undici-types": "~7.19.0" } }, "sha512-sokuT28dxf9JT5Kady1fsXOvI4HVpjZa95NKT5y9PNTIrs2AsobR4GFAA90ZG8M+nxVRLysCXsVj6eGC7Vbrlw=="],
+
     "@types/trusted-types": ["@types/trusted-types@2.0.7", "", {}, "sha512-ScaPdn1dQczgbl0QFTeTOmVHFULt394XJgOQNoyVhZ6r2vLnMLJfBPd53SB52T/3G36VI1/g2MZaX0cwDuXsfw=="],
 
     "acorn": ["acorn@8.16.0", "", { "bin": { "acorn": "bin/acorn" } }, "sha512-UVJyE9MttOsBQIDKw1skb9nAwQuR5wuGD3+82K6JgJlm/Y+KI92oNsMNGZCYdDsVtRHSak0pcV5Dno5+4jh9sw=="],
@@ -211,6 +214,8 @@
 
     "typescript": ["typescript@6.0.3", "", { "bin": { "tsc": "bin/tsc", "tsserver": "bin/tsserver" } }, "sha512-y2TvuxSZPDyQakkFRPZHKFm+KKVqIisdg9/CZwm9ftvKXLP8NRWj38/ODjNbr43SsoXqNuAisEf1GdCxqWcdBw=="],
 
+    "undici-types": ["undici-types@7.19.2", "", {}, "sha512-qYVnV5OEm2AW8cJMCpdV20CDyaN3g0AjDlOGf1OW4iaDEx8MwdtChUp4zu4H0VP3nDRF/8RKWH+IPp9uW0YGZg=="],
+
     "util-deprecate": ["util-deprecate@1.0.2", "", {}, "sha512-EPD5q1uXyFxJpCrLnCc1nHnq3gOa6DZBocAIiI2TaSCA7VCJ1UJDMagCzIkXNsUYfD1daK//LTEQ8xiIbrHtcw=="],
 
     "vite": ["vite@8.0.11", "", { "dependencies": { "lightningcss": "^1.32.0", "picomatch": "^4.0.4", "postcss": "^8.5.14", "rolldown": "1.0.0-rc.18", "tinyglobby": "^0.2.16" }, "optionalDependencies": { "fsevents": "~2.3.3" }, "peerDependencies": { "@types/node": "^20.19.0 || >=22.12.0", "@vitejs/devtools": "^0.1.18", "esbuild": "^0.27.0 || ^0.28.0", "jiti": ">=1.21.0", "less": "^4.0.0", "sass": "^1.70.0", "sass-embedded": "^1.70.0", "stylus": ">=0.54.8", "sugarss": "^5.0.0", "terser": "^5.16.0", "tsx": "^4.8.1", "yaml": "^2.4.2" }, "optionalPeers": ["@types/node", "@vitejs/devtools", "esbuild", "jiti", "less", "sass", "sass-embedded", "stylus", "sugarss", "terser", "tsx", "yaml"], "bin": { "vite": "bin/vite.js" } }, "sha512-Jz1mxtUBR5xTT65VOdJZUUeoyLtqljmFkiUXhPTLZka3RDc9vpi/xXkyrnsdRcm2lIi3l3GPMnAidTsEGIj3Ow=="],
diff --git a/package.json b/package.json
index 9b607d8..80e5453 100644
--- a/package.json
+++ b/package.json
@@ -15,6 +15,7 @@
 		"@sveltejs/adapter-auto": "^7.0.1",
 		"@sveltejs/kit": "^2.57.0",
 		"@sveltejs/vite-plugin-svelte": "^7.0.0",
+		"@types/node": "^25.6.2",
 		"svelte": "^5.55.2",
 		"svelte-check": "^4.4.6",
 		"typescript": "^6.0.2",
diff --git a/src/lib/api.js b/src/lib/api.js
deleted file mode 100644
index d4e3ede..0000000
--- a/src/lib/api.js
+++ /dev/null
@@ -1,27 +0,0 @@
-export async function fetchStations(fetch = globalThis.fetch) {
-  const res = await fetch('http://37100lab.it:8101/api/campagne_map_data');
-  if (!res.ok) throw new Error(`Errore HTTP ${res.status}`);
-  const geojson = await res.json();
-  return geojson.features
-    .map(f => ({ ...f.properties, pk: parseInt(f.properties.pk, 10) }))
-    .sort((a, b) => b.pk - a.pk);
-}
-
-export async function fetchDay(id, day, signal) {
-  // Converte YYYY-M-D (da formatDayParam) in YYYY-MM-DD per la chiamata API
-  const [y, m, d] = day.split('-');
-  const date = `${y}-${m.padStart(2, '0')}-${d.padStart(2, '0')}`;
-
-  // L'API risponde con 5xx transienti: tre tentativi limitano i buchi nel dataset scaricato.
-  for (let attempt = 0; attempt < 3; attempt++) {
-    try {
-      const res = await fetch(`/api/get_station_data?id=${id}&date=${date}`, { signal });
-      if (!res.ok) throw new Error(`HTTP ${res.status}`);
-      return await res.json();
-    } catch (e) {
-      // La cancellazione non è un errore: uscire subito senza consumare altri retry.
-      if (e.name === 'AbortError') return [];
-      if (attempt === 2) return [];
-    }
-  }
-}
diff --git a/src/lib/api.ts b/src/lib/api.ts
new file mode 100644
index 0000000..9785122
--- /dev/null
+++ b/src/lib/api.ts
@@ -0,0 +1,32 @@
+import type { Station, Measurement } from './types.js';
+
+export async function fetchStations(fetch = globalThis.fetch): Promise<Station[]> {
+  const res = await fetch('http://37100lab.it:8101/api/campagne_map_data');
+  if (!res.ok) throw new Error(`Errore HTTP ${res.status}`);
+  const geojson = await res.json();
+  return (geojson.features as Array<{ properties: Record<string, unknown> }>)
+    .map(f => ({
+      pk: parseInt(f.properties.pk as string, 10),
+      title: f.properties.title as string,
+      created_at: f.properties.created_at as string,
+      ended_at: f.properties.ended_at as string | null,
+    }))
+    .sort((a, b) => b.pk - a.pk);
+}
+
+export async function fetchDay(id: number, day: string, signal: AbortSignal): Promise<Measurement[]> {
+  const [y, m, d] = day.split('-');
+  const date = `${y}-${m.padStart(2, '0')}-${d.padStart(2, '0')}`;
+
+  for (let attempt = 0; attempt < 3; attempt++) {
+    try {
+      const res = await fetch(`/api/get_station_data?id=${id}&date=${date}`, { signal });
+      if (!res.ok) throw new Error(`HTTP ${res.status}`);
+      return await res.json() as Measurement[];
+    } catch (e) {
+      if (e instanceof Error && e.name === 'AbortError') return [];
+      if (attempt === 2) return [];
+    }
+  }
+  return [];
+}
diff --git a/src/lib/components/StationList.svelte b/src/lib/components/StationList.svelte
index d100b79..d5f3e4b 100644
--- a/src/lib/components/StationList.svelte
+++ b/src/lib/components/StationList.svelte
@@ -1,18 +1,19 @@
-<script>
+<script lang="ts">
   import StationRow from './StationRow.svelte';
   import groups from '$lib/groups.json';
+  import type { Station } from '$lib/types.js';
 
-  let { stations = [] } = $props();
+  let { stations = [] }: { stations: Station[] } = $props();
 
   // Set per lookup O(1): con molte centraline, includes() su array per ogni riga sarebbe O(n²).
   const groupedIds = new Set(groups.flatMap(g => g.ids));
 
   // Le attive appaiono prima delle terminate per dare prominenza alle stazioni in funzione.
-  function sortStations(items) {
+  function sortStations(items: Station[]): Station[] {
     return [...items].sort((a, b) => {
       if (a.ended_at === null && b.ended_at !== null) return -1;
       if (a.ended_at !== null && b.ended_at === null) return 1;
-      return new Date(b.created_at) - new Date(a.created_at);
+      return new Date(b.created_at).getTime() - new Date(a.created_at).getTime();
     });
   }
 
diff --git a/src/lib/components/StationRow.svelte b/src/lib/components/StationRow.svelte
index 64cbbb3..1b5b966 100644
--- a/src/lib/components/StationRow.svelte
+++ b/src/lib/components/StationRow.svelte
@@ -1,13 +1,14 @@
-<script>
+<script lang="ts">
   import { onDestroy } from 'svelte';
   import { getDayRange, formatDayParam } from '$lib/timezone.js';
   import { fetchDay } from '$lib/api.js';
   import { buildCsv, downloadBlob, buildDayFilename, buildZipFilename } from '$lib/csv.js';
   import { enqueue } from '$lib/download-pool.js';
+  import type { Station, Measurement } from '$lib/types.js';
 
-  let { station } = $props();
+  let { station }: { station: Station } = $props();
 
-  const formatDate = d => new Intl.DateTimeFormat('it-IT', {
+  const formatDate = (d: string) => new Intl.DateTimeFormat('it-IT', {
     timeZone: 'Europe/Rome',
     day: '2-digit',
     month: '2-digit',
@@ -16,12 +17,12 @@
 
   const isActive = $derived(station.ended_at === null);
   const createdDate = $derived(formatDate(station.created_at));
-  const endDate = $derived(isActive ? null : formatDate(station.ended_at));
+  const endDate = $derived(isActive ? null : formatDate(station.ended_at!));
 
   let downloading = $state(false);
   let cancelling = $state(false);
   let completed = $state(false);
-  let controller = null;
+  let controller: AbortController | null = null;
   let currentDay = $state(0);
   let totalDays = $state(0);
 
@@ -37,7 +38,7 @@
     totalDays = days.length;
     currentDay = 0;
 
-    const resultsByDay = new Array(days.length);
+    const resultsByDay: Measurement[][] = new Array(days.length);
 
     await Promise.all(days.map((day, idx) =>
       enqueue(async () => {
@@ -53,7 +54,7 @@
 
       if (!signal.aborted) {
         const zip = new JSZip();
-        let allMeasurements = [];
+        let allMeasurements: Measurement[] = [];
 
         for (let i = 0; i < days.length; i++) {
           const measurements = resultsByDay[i];
diff --git a/src/lib/csv.js b/src/lib/csv.ts
similarity index 75%
rename from src/lib/csv.js
rename to src/lib/csv.ts
index 2ebdeb1..f7fd0a2 100644
--- a/src/lib/csv.js
+++ b/src/lib/csv.ts
@@ -1,6 +1,7 @@
+import type { Measurement } from './types.js';
 import { formatTimestampRome, ROME } from './timezone.js';
 
-export function buildCsv(measurements, includeDate = true) {
+export function buildCsv(measurements: Measurement[], includeDate = true): string {
   const header = includeDate
     ? '"Data","Ora","Temperatura","Umidità","PM10"'
     : '"Ora","Temperatura","Umidità","PM10"';
@@ -14,7 +15,7 @@ export function buildCsv(measurements, includeDate = true) {
   return '' + [header, ...rows].join('\n');
 }
 
-export function downloadBlob(blob, filename) {
+export function downloadBlob(blob: Blob, filename: string): void {
   const url = URL.createObjectURL(blob);
   const a = document.createElement('a');
   a.href = url;
@@ -23,11 +24,11 @@ export function downloadBlob(blob, filename) {
   URL.revokeObjectURL(url);
 }
 
-export function buildDayFilename(date) {
+export function buildDayFilename(date: Date): string {
   return new Intl.DateTimeFormat('en-CA', { timeZone: ROME }).format(date) + '.csv';
 }
 
-export function buildZipFilename(title, id) {
+export function buildZipFilename(title: string, id: number): string {
   const sanitized = title.replace(/ /g, '_').replace(/[^a-zA-Z0-9_]/g, '');
   return `${sanitized}_(${id}).zip`;
 }
diff --git a/src/lib/download-pool.js b/src/lib/download-pool.js
deleted file mode 100644
index 42890ec..0000000
--- a/src/lib/download-pool.js
+++ /dev/null
@@ -1,26 +0,0 @@
-// Limita le richieste HTTP simultanee per non sovraccaricare l'API del server.
-export const DOWNLOAD_WORKERS = 3;
-
-let active = 0;
-const queue = [];
-
-function next() {
-  while (active < DOWNLOAD_WORKERS && queue.length) {
-    active++;
-    const { fn, resolve } = queue.shift();
-    // Promise.resolve() garantisce che fn() sia trattato come asincrono anche se
-    // restituisse un valore sincrono, rendendo il finally sempre raggiungibile.
-    Promise.resolve(fn()).then(resolve).finally(() => {
-      active--;
-      // Rientrata ricorsiva: ogni job completato sveglia il prossimo in coda.
-      next();
-    });
-  }
-}
-
-export function enqueue(fn) {
-  return new Promise(resolve => {
-    queue.push({ fn, resolve });
-    next();
-  });
-}
diff --git a/src/lib/download-pool.ts b/src/lib/download-pool.ts
new file mode 100644
index 0000000..b480052
--- /dev/null
+++ b/src/lib/download-pool.ts
@@ -0,0 +1,24 @@
+export const DOWNLOAD_WORKERS = 3;
+
+type Job = { fn: () => Promise<void>; resolve: () => void };
+
+let active = 0;
+const queue: Job[] = [];
+
+function next(): void {
+  while (active < DOWNLOAD_WORKERS && queue.length) {
+    active++;
+    const { fn, resolve } = queue.shift()!;
+    Promise.resolve(fn()).then(resolve).finally(() => {
+      active--;
+      next();
+    });
+  }
+}
+
+export function enqueue(fn: () => Promise<void>): Promise<void> {
+  return new Promise(resolve => {
+    queue.push({ fn, resolve });
+    next();
+  });
+}
diff --git a/src/lib/timezone.js b/src/lib/timezone.ts
similarity index 57%
rename from src/lib/timezone.js
rename to src/lib/timezone.ts
index 8a10496..c952a6f 100644
--- a/src/lib/timezone.js
+++ b/src/lib/timezone.ts
@@ -1,21 +1,18 @@
 export const ROME = 'Europe/Rome';
 
-// Pre-calcolato una volta: viene chiamato per ogni riga del CSV, potenzialmente decine di migliaia di volte.
 const PAD2 = Array.from({ length: 100 }, (_, i) => String(i).padStart(2, '0'));
 
-// L'offset CET/CEST cambia solo due volte l'anno: cachare evita una chiamata Intl per ogni timestamp.
-const offsetCache = new Map();
+const offsetCache = new Map<string, number>();
 
-function getRomeOffsetMs(date) {
+function getRomeOffsetMs(date: Date): number {
   const key = `${date.getUTCFullYear()}-${date.getUTCMonth()}-${date.getUTCDate()}-${date.getUTCHours()}`;
-  if (offsetCache.has(key)) return offsetCache.get(key);
+  if (offsetCache.has(key)) return offsetCache.get(key)!;
 
   const romeHour = parseInt(
     new Intl.DateTimeFormat('en', { timeZone: ROME, hour: 'numeric', hour12: false }).format(date),
     10
   );
   let diff = romeHour - date.getUTCHours();
-  // Se diff supera ±12 le ore attraversano mezzanotte UTC: il salto va corretto.
   if (diff > 12) diff -= 24;
   if (diff < -12) diff += 24;
   const offsetMs = diff * 3_600_000;
@@ -23,11 +20,9 @@ function getRomeOffsetMs(date) {
   return offsetMs;
 }
 
-export function formatTimestampRome(isoString) {
+export function formatTimestampRome(isoString: string): string {
   const d = new Date(isoString);
   const frac = Math.floor(d.getMilliseconds() / 100);
-  // Shift manuale invece di toLocaleString: controllo totale sul formato,
-  // indipendente dall'implementazione Intl specifica del browser.
   const r = new Date(d.getTime() + getRomeOffsetMs(d));
 
   const dd = PAD2[r.getUTCDate()];
@@ -40,9 +35,7 @@ export function formatTimestampRome(isoString) {
   return `${dd}/${mo}/${yyyy} ${hh}:${mm}:${ss}.${frac}`;
 }
 
-export function formatDayParam(date) {
-  // formatToParts garantisce valori senza zero-padding, a differenza di format()
-  // il cui output dipende dalla localizzazione del browser.
+export function formatDayParam(date: Date): string {
   const parts = new Intl.DateTimeFormat('it-IT', {
     timeZone: ROME,
     year: 'numeric',
@@ -50,22 +43,19 @@ export function formatDayParam(date) {
     day: 'numeric',
   }).formatToParts(date);
 
-  const get = type => parts.find(p => p.type === type).value;
+  const get = (type: string) => parts.find(p => p.type === type)!.value;
   return `${get('year')}-${get('month')}-${get('day')}`;
 }
 
-export function getDayRange(startIsoUtc, endIsoUtc) {
-  // en-CA produce YYYY-MM-DD, l'unico formato ISO interpretato uniformemente da tutti i browser.
-  const toRomeDateString = date => new Intl.DateTimeFormat('en-CA', {
+export function getDayRange(startIsoUtc: string, endIsoUtc: string | null): Date[] {
+  const toRomeDateString = (date: Date) => new Intl.DateTimeFormat('en-CA', {
     timeZone: ROME,
   }).format(date);
 
   const startStr = toRomeDateString(new Date(startIsoUtc));
   const endStr = toRomeDateString(endIsoUtc ? new Date(endIsoUtc) : new Date());
 
-  const days = [];
-  // Mezzogiorno UTC (13:00/14:00 a Roma) non attraversa mai un cambio data locale,
-  // neanche durante il passaggio ora legale/solare.
+  const days: Date[] = [];
   let cursor = new Date(`${startStr}T12:00:00Z`);
   const end = new Date(`${endStr}T12:00:00Z`);
 
diff --git a/src/lib/types.ts b/src/lib/types.ts
new file mode 100644
index 0000000..a9140f6
--- /dev/null
+++ b/src/lib/types.ts
@@ -0,0 +1,13 @@
+export interface Station {
+  pk: number;
+  title: string;
+  created_at: string;
+  ended_at: string | null;
+}
+
+export interface Measurement {
+  temp: number;
+  umid: number;
+  pm10: number;
+  time: string;
+}
diff --git a/src/routes/+layout.svelte b/src/routes/+layout.svelte
index 726b46c..9b776b7 100644
--- a/src/routes/+layout.svelte
+++ b/src/routes/+layout.svelte
@@ -1,4 +1,4 @@
-<script>
+<script lang="ts">
 	import '../app.css';
 	let { children } = $props();
 </script>
diff --git a/src/routes/+page.server.js b/src/routes/+page.server.ts
similarity index 67%
rename from src/routes/+page.server.js
rename to src/routes/+page.server.ts
index 7fefc03..679fa3d 100644
--- a/src/routes/+page.server.js
+++ b/src/routes/+page.server.ts
@@ -1,9 +1,10 @@
+import type { PageServerLoad } from './$types.js';
 import { fetchStations } from '$lib/api.js';
 
-export async function load({ fetch }) {
+export const load: PageServerLoad = async ({ fetch }) => {
   try {
     return { stations: await fetchStations(fetch) };
   } catch {
     return { stations: [], loadError: 'Impossibile caricare le centraline. Controlla la connessione e riprova.' };
   }
-}
+};
diff --git a/src/routes/+page.svelte b/src/routes/+page.svelte
index 0b6d464..63ba7c8 100644
--- a/src/routes/+page.svelte
+++ b/src/routes/+page.svelte
@@ -1,4 +1,4 @@
-<script>
+<script lang="ts">
   import StationList from '$lib/components/StationList.svelte';
 
   let { data } = $props();
diff --git a/src/routes/api/get_station_data/+server.js b/src/routes/api/get_station_data/+server.ts
similarity index 68%
rename from src/routes/api/get_station_data/+server.js
rename to src/routes/api/get_station_data/+server.ts
index 9feb675..3ada459 100644
--- a/src/routes/api/get_station_data/+server.js
+++ b/src/routes/api/get_station_data/+server.ts
@@ -1,16 +1,21 @@
 import { dev } from '$app/environment';
+import type { RequestHandler } from './$types.js';
 
-function cacheControl(date) {
+function cacheControl(date: string): string {
   if (dev) return 'no-store';
-  const toIso = d => new Intl.DateTimeFormat('en-CA', { timeZone: 'Europe/Rome' }).format(d);
+  const toIso = (d: Date) => new Intl.DateTimeFormat('en-CA', { timeZone: 'Europe/Rome' }).format(d);
   const yesterday = toIso(new Date(Date.now() - 86_400_000));
   return date < yesterday ? 'public, max-age=604800' : 'public, max-age=60';
 }
 
-export async function GET({ url }) {
+export const GET: RequestHandler = async ({ url }) => {
   const id = url.searchParams.get('id');
   const date = url.searchParams.get('date'); // YYYY-MM-DD
 
+  if (!id || !date) {
+    return new Response('[]', { status: 400, headers: { 'content-type': 'application/json' } });
+  }
+
   // Il backend vuole YYYY-M-D senza zero-padding
   const [y, m, d] = date.split('-');
   const day = `${parseInt(y)}-${parseInt(m)}-${parseInt(d)}`;
@@ -25,7 +30,8 @@ export async function GET({ url }) {
   // Il backend Python emette NaN/Infinity per valori mancanti o fuori range,
   // che non sono JSON valido e farebbero esplodere JSON.parse.
   const sanitized = text.replace(/(?<=[:\s\[,])(?:nan|inf|-inf|infinity|-infinity)(?=[,\]\s}])/gi, 'null');
-  const misure = (JSON.parse(sanitized).misure ?? [])
+  type RawMeasurement = { temp: number; umid: number; pm10: number; time: string };
+  const misure = ((JSON.parse(sanitized).misure ?? []) as RawMeasurement[])
     .filter(m => m != null && Number.isFinite(new Date(m.time).getTime()));
 
   return new Response(JSON.stringify(misure), {
@@ -34,4 +40,4 @@ export async function GET({ url }) {
       'cache-control': cacheControl(date),
     },
   });
-}
+};