diff --git a/.jules/bolt.md b/.jules/bolt.md
index 9345ee7a..cf2dd851 100644
--- a/.jules/bolt.md
+++ b/.jules/bolt.md
@@ -2,3 +2,8 @@
 
 **Learning:** In Next.js/React applications, when grouping items (like schedules or talks) into a `Map` where the values are arrays, using the array spread operator `[...existing, item]` inside a loop (like `forEach` or `map`) causes amortized O(N^2) memory allocations and unnecessary Garbage Collection overhead.
 **Action:** Always use `.push()` on the existing array reference if the data structure permits local mutation. For strict ESLint configurations enforcing `no-restricted-syntax`, extract the existing array, push to it, and handle the fallback elegantly (`if (!existing) { map.set(key, [item]); } else { existing.push(item); }`).
+
+## 2024-05-31 - Optimize Next.js static generation builds with parallel data fetching
+
+**Learning:** Sequential `for...of` loops used for fetching dynamic page dependencies inside Next.js build-time functions like `generateStaticParams` (or `sitemap.ts`) block the thread and significantly increase total site build duration.
+**Action:** When gathering parameters for static routes across large array sets (such as mapping years or categories), replace sequential `for...of` iteration with parallel execution using `Promise.all(array.map(...))`. Then, correctly aggregate nested outputs utilizing `.flat()` or `.flatMap()`, and preserve per-item `try/catch` fallbacks to prevent a single item failure from crashing the entire batch build.
diff --git a/app/[year]/job-offers/[companyName]/page.tsx b/app/[year]/job-offers/[companyName]/page.tsx
index a45ee546..23143704 100644
--- a/app/[year]/job-offers/[companyName]/page.tsx
+++ b/app/[year]/job-offers/[companyName]/page.tsx
@@ -20,19 +20,22 @@ export const revalidate = 3600;
 
 export async function generateStaticParams() {
   const years = getAvailableEditions();
-  const params = [];
-
-  for (const year of years) {
-    const companies = await getJobOffersForEdition(year);
-    for (const company of companies) {
-      params.push({
-        year,
-        companyName: company.id,
-      });
-    }
-  }
 
-  return params;
+  const nestedParams = await Promise.all(
+    years.map(async (year) => {
+      const params: { year: string; companyName: string }[] = [];
+      const companies = await getJobOffersForEdition(year);
+      for (const company of companies) {
+        params.push({
+          year,
+          companyName: company.id,
+        });
+      }
+      return params;
+    })
+  );
+
+  return nestedParams.flat();
 }
 
 export async function generateMetadata({ params }: CompanyJobOffersPageProps): Promise<Metadata> {
diff --git a/app/[year]/speakers/[speakerId]/page.tsx b/app/[year]/speakers/[speakerId]/page.tsx
index 62b234bd..1467d5b8 100644
--- a/app/[year]/speakers/[speakerId]/page.tsx
+++ b/app/[year]/speakers/[speakerId]/page.tsx
@@ -20,20 +20,23 @@ interface SpeakerDetailProps {
 
 export async function generateStaticParams() {
   const years = getArchivedEditions();
-  const params = [];
 
-  for (const year of years) {
-    try {
-      const speakers = await getSpeakers(year);
-      for (const speaker of speakers) {
-        params.push({ year, speakerId: speaker.id });
+  const nestedParams = await Promise.all(
+    years.map(async (year) => {
+      const params: { year: string; speakerId: string }[] = [];
+      try {
+        const speakers = await getSpeakers(year);
+        for (const speaker of speakers) {
+          params.push({ year, speakerId: speaker.id });
+        }
+      } catch (error) {
+        console.warn(`Failed to fetch speakers for year ${year}:`, error);
       }
-    } catch (error) {
-      console.warn(`Failed to fetch speakers for year ${year}:`, error);
-    }
-  }
+      return params;
+    })
+  );
 
-  return params;
+  return nestedParams.flat();
 }
 
 export async function generateMetadata({ params }: SpeakerDetailProps): Promise<Metadata> {
diff --git a/app/[year]/tags/[tag]/page.tsx b/app/[year]/tags/[tag]/page.tsx
index 35c74f61..e051dd7e 100644
--- a/app/[year]/tags/[tag]/page.tsx
+++ b/app/[year]/tags/[tag]/page.tsx
@@ -18,27 +18,30 @@ export const dynamicParams = false;
 
 export async function generateStaticParams() {
   const years = getArchivedEditions();
-  const params = [];
 
-  for (const year of years) {
-    try {
-      const sessionGroups = await getTalks(year);
-      const allTalks = sessionGroups.flatMap((group) => group.sessions);
-      const allTags = new Set<string>();
-
-      for (const talk of allTalks) {
-        getTagsFromTalk(talk).forEach((tag) => allTags.add(tag));
-      }
-
-      for (const tag of allTags) {
-        params.push({ year, tag: tag.replaceAll(" ", "-").toLowerCase() });
+  const nestedParams = await Promise.all(
+    years.map(async (year) => {
+      const params: { year: string; tag: string }[] = [];
+      try {
+        const sessionGroups = await getTalks(year);
+        const allTalks = sessionGroups.flatMap((group) => group.sessions);
+        const allTags = new Set<string>();
+
+        for (const talk of allTalks) {
+          getTagsFromTalk(talk).forEach((tag) => allTags.add(tag));
+        }
+
+        for (const tag of allTags) {
+          params.push({ year, tag: tag.replaceAll(" ", "-").toLowerCase() });
+        }
+      } catch (error) {
+        console.warn(`Failed to fetch talks for year ${year}:`, error);
       }
-    } catch (error) {
-      console.warn(`Failed to fetch talks for year ${year}:`, error);
-    }
-  }
+      return params;
+    })
+  );
 
-  return params;
+  return nestedParams.flat();
 }
 
 export async function generateMetadata({ params }: Readonly<TagPageProps>): Promise<Metadata> {
diff --git a/app/[year]/talks/[talkId]/page.tsx b/app/[year]/talks/[talkId]/page.tsx
index 88f08655..e07ca1fb 100644
--- a/app/[year]/talks/[talkId]/page.tsx
+++ b/app/[year]/talks/[talkId]/page.tsx
@@ -29,21 +29,24 @@ interface TalkDetailProps {
 
 export async function generateStaticParams() {
   const years = getArchivedEditions();
-  const params = [];
-
-  for (const year of years) {
-    try {
-      const sessionGroups = await getTalks(year);
-      const allTalks = sessionGroups.flatMap((group) => group.sessions);
-      for (const talk of allTalks) {
-        params.push({ year, talkId: talk.id });
+
+  const nestedParams = await Promise.all(
+    years.map(async (year) => {
+      const params: { year: string; talkId: string }[] = [];
+      try {
+        const sessionGroups = await getTalks(year);
+        const allTalks = sessionGroups.flatMap((group) => group.sessions);
+        for (const talk of allTalks) {
+          params.push({ year, talkId: talk.id });
+        }
+      } catch (error) {
+        console.warn(`Failed to fetch talks for year ${year}:`, error);
       }
-    } catch (error) {
-      console.warn(`Failed to fetch talks for year ${year}:`, error);
-    }
-  }
+      return params;
+    })
+  );
 
-  return params;
+  return nestedParams.flat();
 }
 
 export async function generateMetadata({ params }: TalkDetailProps): Promise<Metadata> {