diff --git a/src/app/api/me/folders/[folderId]/route.ts b/src/app/api/me/folders/[folderId]/route.ts
new file mode 100644
index 00000000..d00a3bfd
--- /dev/null
+++ b/src/app/api/me/folders/[folderId]/route.ts
@@ -0,0 +1,116 @@
+import { NextRequest, NextResponse } from "next/server";
+import { z } from "zod";
+import { and, eq, inArray } from "drizzle-orm";
+import { getServerSession } from "next-auth";
+import { AuthOptions } from "@/app/api/auth/[...nextauth]/authOptions";
+import { db } from "@/app/db/db";
+import {
+  userPortfolioConfig,
+  userPortfolioFolders,
+} from "@/app/db/schema/user_portfolio_config";
+import { planFolderDeletion } from "@/app/lib/portfolioUserConfig";
+
+const RenameSchema = z.object({
+  name: z.string().trim().min(1).max(120),
+});
+
+const FolderIdSchema = z.string().regex(/^\d+$/);
+
+export async function PATCH(
+  req: NextRequest,
+  props: { params: Promise<{ folderId: string }> },
+) {
+  try {
+    const session = await getServerSession(AuthOptions);
+    if (!session?.user?.dbId) {
+      return NextResponse.json({ error: "Unauthenticated" }, { status: 401 });
+    }
+    const userId = session.user.dbId;
+
+    const { folderId } = await props.params;
+    if (!FolderIdSchema.safeParse(folderId).success) {
+      return NextResponse.json({ error: "Folder not found" }, { status: 404 });
+    }
+
+    const parsed = RenameSchema.safeParse(await req.json());
+    if (!parsed.success) {
+      return NextResponse.json({ error: "Invalid folder name" }, { status: 400 });
+    }
+
+    const renamed = await db
+      .update(userPortfolioFolders)
+      .set({ name: parsed.data.name, updatedAt: new Date() })
+      .where(
+        and(
+          eq(userPortfolioFolders.id, BigInt(folderId)),
+          eq(userPortfolioFolders.userId, userId),
+        ),
+      )
+      .returning({ id: userPortfolioFolders.id });
+
+    if (renamed.length === 0) {
+      return NextResponse.json({ error: "Folder not found" }, { status: 404 });
+    }
+    return NextResponse.json({ ok: true });
+  } catch (err) {
+    console.error("Error renaming folder:", err);
+    return NextResponse.json({ error: "Server error" }, { status: 500 });
+  }
+}
+
+// Folder deletion never deletes portfolios — it unfiles them. The same-owner
+// FK is NO ACTION, so unfile + delete must happen in one transaction,
+// unfile first (see planFolderDeletion).
+export async function DELETE(
+  _req: NextRequest,
+  props: { params: Promise<{ folderId: string }> },
+) {
+  try {
+    const session = await getServerSession(AuthOptions);
+    if (!session?.user?.dbId) {
+      return NextResponse.json({ error: "Unauthenticated" }, { status: 401 });
+    }
+    const userId = session.user.dbId;
+
+    const { folderId } = await props.params;
+    if (!FolderIdSchema.safeParse(folderId).success) {
+      return NextResponse.json({ error: "Folder not found" }, { status: 404 });
+    }
+
+    const configs = await db
+      .select({
+        id: userPortfolioConfig.id,
+        folderId: userPortfolioConfig.folderId,
+      })
+      .from(userPortfolioConfig)
+      .where(eq(userPortfolioConfig.userId, userId));
+
+    const plan = planFolderDeletion({ folderId: BigInt(folderId), configs });
+
+    const deleted = await db.transaction(async (tx) => {
+      if (plan.unfileConfigIds.length > 0) {
+        await tx
+          .update(userPortfolioConfig)
+          .set({ folderId: null, updatedAt: new Date() })
+          .where(inArray(userPortfolioConfig.id, plan.unfileConfigIds));
+      }
+      return tx
+        .delete(userPortfolioFolders)
+        .where(
+          and(
+            eq(userPortfolioFolders.id, plan.deleteFolderId),
+            eq(userPortfolioFolders.userId, userId),
+          ),
+        )
+        .returning({ id: userPortfolioFolders.id });
+    });
+
+    if (deleted.length === 0) {
+      return NextResponse.json({ error: "Folder not found" }, { status: 404 });
+    }
+    return NextResponse.json({ ok: true });
+  } catch (err) {
+    console.error("Error deleting folder:", err);
+    return NextResponse.json({ error: "Server error" }, { status: 500 });
+  }
+}
diff --git a/src/app/api/me/folders/reorder/route.ts b/src/app/api/me/folders/reorder/route.ts
new file mode 100644
index 00000000..3addbd8e
--- /dev/null
+++ b/src/app/api/me/folders/reorder/route.ts
@@ -0,0 +1,62 @@
+import { NextRequest, NextResponse } from "next/server";
+import { z } from "zod";
+import { and, eq } from "drizzle-orm";
+import { getServerSession } from "next-auth";
+import { AuthOptions } from "@/app/api/auth/[...nextauth]/authOptions";
+import { db } from "@/app/db/db";
+import { userPortfolioFolders } from "@/app/db/schema/user_portfolio_config";
+import { planFolderReorder } from "@/app/lib/portfolioUserConfig";
+
+const ReorderSchema = z.object({
+  orderedIds: z.array(z.string().regex(/^\d+$/)),
+});
+
+// Drag-and-drop reorder: the client sends the FULL ordered folder id list in
+// one request; positions are renumbered in a single transaction so the write
+// is idempotent and can't drift.
+export async function PATCH(req: NextRequest) {
+  try {
+    const session = await getServerSession(AuthOptions);
+    if (!session?.user?.dbId) {
+      return NextResponse.json({ error: "Unauthenticated" }, { status: 401 });
+    }
+    const userId = session.user.dbId;
+
+    const parsed = ReorderSchema.safeParse(await req.json());
+    if (!parsed.success) {
+      return NextResponse.json({ error: "Invalid folder order" }, { status: 400 });
+    }
+
+    const current = await db
+      .select({ id: userPortfolioFolders.id })
+      .from(userPortfolioFolders)
+      .where(eq(userPortfolioFolders.userId, userId));
+
+    const plan = planFolderReorder({
+      currentIds: current.map((f) => f.id),
+      orderedIds: parsed.data.orderedIds.map(BigInt),
+    });
+    if ("error" in plan) {
+      return NextResponse.json({ error: plan.error }, { status: 400 });
+    }
+
+    await db.transaction(async (tx) => {
+      for (const { id, position } of plan.updates) {
+        await tx
+          .update(userPortfolioFolders)
+          .set({ position, updatedAt: new Date() })
+          .where(
+            and(
+              eq(userPortfolioFolders.id, id),
+              eq(userPortfolioFolders.userId, userId),
+            ),
+          );
+      }
+    });
+
+    return NextResponse.json({ ok: true });
+  } catch (err) {
+    console.error("Error reordering folders:", err);
+    return NextResponse.json({ error: "Server error" }, { status: 500 });
+  }
+}
diff --git a/src/app/api/me/folders/route.ts b/src/app/api/me/folders/route.ts
new file mode 100644
index 00000000..1479f90b
--- /dev/null
+++ b/src/app/api/me/folders/route.ts
@@ -0,0 +1,53 @@
+import { NextRequest, NextResponse } from "next/server";
+import { z } from "zod";
+import { eq, sql } from "drizzle-orm";
+import { getServerSession } from "next-auth";
+import { AuthOptions } from "@/app/api/auth/[...nextauth]/authOptions";
+import { db } from "@/app/db/db";
+import { userPortfolioFolders } from "@/app/db/schema/user_portfolio_config";
+
+const CreateFolderSchema = z.object({
+  name: z.string().trim().min(1).max(120),
+});
+
+export async function POST(req: NextRequest) {
+  try {
+    const session = await getServerSession(AuthOptions);
+    if (!session?.user?.dbId) {
+      return NextResponse.json({ error: "Unauthenticated" }, { status: 401 });
+    }
+    const userId = session.user.dbId;
+
+    const parsed = CreateFolderSchema.safeParse(await req.json());
+    if (!parsed.success) {
+      return NextResponse.json({ error: "Invalid folder name" }, { status: 400 });
+    }
+
+    // New folders go last: position = current folder count.
+    const [created] = await db
+      .insert(userPortfolioFolders)
+      .values({
+        userId,
+        name: parsed.data.name,
+        position: sql`(select count(*) from ${userPortfolioFolders} where ${eq(
+          userPortfolioFolders.userId,
+          userId,
+        )})`,
+      })
+      .returning();
+
+    return NextResponse.json(
+      {
+        folder: {
+          id: created.id.toString(),
+          name: created.name,
+          position: created.position,
+        },
+      },
+      { status: 201 },
+    );
+  } catch (err) {
+    console.error("Error creating folder:", err);
+    return NextResponse.json({ error: "Server error" }, { status: 500 });
+  }
+}
diff --git a/src/app/api/me/portfolio-home/route.ts b/src/app/api/me/portfolio-home/route.ts
new file mode 100644
index 00000000..4fb62a7c
--- /dev/null
+++ b/src/app/api/me/portfolio-home/route.ts
@@ -0,0 +1,65 @@
+import { NextResponse } from "next/server";
+import { eq } from "drizzle-orm";
+import { getServerSession } from "next-auth";
+import { AuthOptions } from "@/app/api/auth/[...nextauth]/authOptions";
+import { db } from "@/app/db/db";
+import { getPortfolios } from "@/app/home/utils";
+import {
+  userPortfolioConfig,
+  userPortfolioFolders,
+} from "@/app/db/schema/user_portfolio_config";
+import { groupPortfoliosForHome } from "@/app/lib/portfolioUserConfig";
+
+// Everything the home page renders: the caller's portfolios grouped by their
+// personal folders, with starred float and a most-recently-starred list.
+export async function GET() {
+  try {
+    const session = await getServerSession(AuthOptions);
+    if (!session?.user?.dbId) {
+      return NextResponse.json({ error: "Unauthenticated" }, { status: 401 });
+    }
+    const userId = session.user.dbId;
+
+    const [portfolios, configs, folders] = await Promise.all([
+      getPortfolios(userId),
+      db
+        .select({
+          portfolioId: userPortfolioConfig.portfolioId,
+          folderId: userPortfolioConfig.folderId,
+          starredAt: userPortfolioConfig.starredAt,
+        })
+        .from(userPortfolioConfig)
+        .where(eq(userPortfolioConfig.userId, userId)),
+      db
+        .select({
+          id: userPortfolioFolders.id,
+          name: userPortfolioFolders.name,
+          position: userPortfolioFolders.position,
+        })
+        .from(userPortfolioFolders)
+        .where(eq(userPortfolioFolders.userId, userId)),
+    ]);
+
+    const starredIds = new Set(
+      configs.filter((c) => c.starredAt !== null).map((c) => c.portfolioId),
+    );
+    const grouped = groupPortfoliosForHome({ portfolios, configs, folders });
+    const body = {
+      folders: grouped.folders,
+      unfiled: grouped.unfiled,
+      starred: grouped.starred,
+      starredIds: [...starredIds],
+    };
+
+    // bigint isn't JSON-serialisable; ids cross the wire as strings.
+    return new NextResponse(
+      JSON.stringify(body, (_key, value) =>
+        typeof value === "bigint" ? value.toString() : value,
+      ),
+      { status: 200, headers: { "content-type": "application/json" } },
+    );
+  } catch (err) {
+    console.error("Error loading portfolio home:", err);
+    return NextResponse.json({ error: "Server error" }, { status: 500 });
+  }
+}
diff --git a/src/app/api/me/portfolios/[portfolioId]/config/route.ts b/src/app/api/me/portfolios/[portfolioId]/config/route.ts
new file mode 100644
index 00000000..7ec6adde
--- /dev/null
+++ b/src/app/api/me/portfolios/[portfolioId]/config/route.ts
@@ -0,0 +1,89 @@
+import { NextRequest, NextResponse } from "next/server";
+import { z } from "zod";
+import { and, eq } from "drizzle-orm";
+import { getServerSession } from "next-auth";
+import { AuthOptions } from "@/app/api/auth/[...nextauth]/authOptions";
+import { db } from "@/app/db/db";
+import { portfolioUsers } from "@/app/db/schema/portfolio";
+import { userPortfolioConfig } from "@/app/db/schema/user_portfolio_config";
+import { buildStarChange } from "@/app/lib/portfolioUserConfig";
+
+const ConfigSchema = z
+  .object({
+    starred: z.boolean().optional(),
+    folderId: z.string().regex(/^\d+$/).nullable().optional(),
+  })
+  .refine((v) => v.starred !== undefined || v.folderId !== undefined, {
+    message: "Nothing to update",
+  });
+
+// Upserts the caller's personal config for one portfolio (star / move to
+// folder). Rows are created lazily: no row means all defaults.
+export async function PATCH(
+  req: NextRequest,
+  props: { params: Promise<{ portfolioId: string }> },
+) {
+  try {
+    const session = await getServerSession(AuthOptions);
+    if (!session?.user?.dbId) {
+      return NextResponse.json({ error: "Unauthenticated" }, { status: 401 });
+    }
+    const userId = session.user.dbId;
+
+    const { portfolioId } = await props.params;
+    if (!/^\d+$/.test(portfolioId)) {
+      return NextResponse.json({ error: "Portfolio not found" }, { status: 404 });
+    }
+
+    const parsed = ConfigSchema.safeParse(await req.json());
+    if (!parsed.success) {
+      return NextResponse.json({ error: "Invalid config" }, { status: 400 });
+    }
+
+    // Config only exists for portfolios the user can actually see.
+    const membership = await db
+      .select({ id: portfolioUsers.id })
+      .from(portfolioUsers)
+      .where(
+        and(
+          eq(portfolioUsers.userId, userId),
+          eq(portfolioUsers.portfolioId, BigInt(portfolioId)),
+        ),
+      );
+    if (membership.length === 0) {
+      return NextResponse.json({ error: "Portfolio not found" }, { status: 404 });
+    }
+
+    const change: Partial<{
+      starredAt: Date | null;
+      folderId: bigint | null;
+    }> = {};
+    if (parsed.data.starred !== undefined) {
+      change.starredAt = buildStarChange({
+        starred: parsed.data.starred,
+        now: new Date(),
+      }).starredAt;
+    }
+    if (parsed.data.folderId !== undefined) {
+      change.folderId =
+        parsed.data.folderId === null ? null : BigInt(parsed.data.folderId);
+    }
+
+    await db
+      .insert(userPortfolioConfig)
+      .values({
+        userId,
+        portfolioId: BigInt(portfolioId),
+        ...change,
+      })
+      .onConflictDoUpdate({
+        target: [userPortfolioConfig.userId, userPortfolioConfig.portfolioId],
+        set: { ...change, updatedAt: new Date() },
+      });
+
+    return NextResponse.json({ ok: true });
+  } catch (err) {
+    console.error("Error updating portfolio config:", err);
+    return NextResponse.json({ error: "Server error" }, { status: 500 });
+  }
+}
diff --git a/src/app/lib/portfolioUserConfig.test.ts b/src/app/lib/portfolioUserConfig.test.ts
new file mode 100644
index 00000000..9ed087b5
--- /dev/null
+++ b/src/app/lib/portfolioUserConfig.test.ts
@@ -0,0 +1,114 @@
+import { describe, expect, it } from "vitest";
+import {
+  buildStarChange,
+  groupPortfoliosForHome,
+  planFolderDeletion,
+  planFolderReorder,
+} from "./portfolioUserConfig";
+
+describe("planFolderReorder", () => {
+  it("renumbers every folder to its index in the requested order", () => {
+    const plan = planFolderReorder({
+      currentIds: [1n, 2n, 3n],
+      orderedIds: [3n, 1n, 2n],
+    });
+
+    expect(plan).toEqual({
+      updates: [
+        { id: 3n, position: 0 },
+        { id: 1n, position: 1 },
+        { id: 2n, position: 2 },
+      ],
+    });
+  });
+
+  it("rejects an order naming a folder the user does not have", () => {
+    const plan = planFolderReorder({
+      currentIds: [1n, 2n],
+      orderedIds: [2n, 99n],
+    });
+
+    expect(plan).toEqual({
+      error: "Folder order does not match your folders",
+    });
+  });
+
+  it("rejects an order that lists the same folder twice", () => {
+    const plan = planFolderReorder({
+      currentIds: [1n, 2n],
+      orderedIds: [1n, 1n, 2n],
+    });
+
+    expect(plan).toEqual({
+      error: "Folder order does not match your folders",
+    });
+  });
+});
+
+describe("groupPortfoliosForHome", () => {
+  it("groups portfolios into folders ordered by position, with the rest unfiled", () => {
+    const grouped = groupPortfoliosForHome({
+      portfolios: [{ id: 1n }, { id: 2n }, { id: 3n }],
+      configs: [
+        { portfolioId: 1n, folderId: 10n, starredAt: null },
+        { portfolioId: 2n, folderId: 11n, starredAt: null },
+      ],
+      folders: [
+        { id: 10n, name: "SHDF Wave 3", position: 1 },
+        { id: 11n, name: "Demos", position: 0 },
+      ],
+    });
+
+    expect(grouped.folders).toEqual([
+      { id: 11n, name: "Demos", portfolios: [{ id: 2n }] },
+      { id: 10n, name: "SHDF Wave 3", portfolios: [{ id: 1n }] },
+    ]);
+    expect(grouped.unfiled).toEqual([{ id: 3n }]);
+  });
+
+  it("floats starred portfolios to the top of their group and lists them most-recently-starred first", () => {
+    const grouped = groupPortfoliosForHome({
+      portfolios: [{ id: 1n }, { id: 2n }, { id: 3n }, { id: 4n }],
+      configs: [
+        { portfolioId: 1n, folderId: 10n, starredAt: null },
+        { portfolioId: 2n, folderId: 10n, starredAt: new Date("2026-07-01") },
+        { portfolioId: 4n, folderId: null, starredAt: new Date("2026-07-05") },
+      ],
+      folders: [{ id: 10n, name: "SHDF Wave 3", position: 0 }],
+    });
+
+    expect(grouped.folders[0].portfolios).toEqual([{ id: 2n }, { id: 1n }]);
+    expect(grouped.unfiled).toEqual([{ id: 4n }, { id: 3n }]);
+    expect(grouped.starred).toEqual([{ id: 4n }, { id: 2n }]);
+  });
+});
+
+describe("planFolderDeletion", () => {
+  it("unfiles exactly the configs in the folder, then deletes the folder", () => {
+    const plan = planFolderDeletion({
+      folderId: 10n,
+      configs: [
+        { id: 1n, folderId: 10n },
+        { id: 2n, folderId: 11n },
+        { id: 3n, folderId: 10n },
+        { id: 4n, folderId: null },
+      ],
+    });
+
+    expect(plan).toEqual({
+      unfileConfigIds: [1n, 3n],
+      deleteFolderId: 10n,
+    });
+  });
+});
+
+describe("buildStarChange", () => {
+  it("starring stamps the moment, unstarring clears it", () => {
+    const now = new Date("2026-07-07T12:00:00Z");
+
+    expect(buildStarChange({ starred: true, now })).toEqual({ starredAt: now });
+    expect(buildStarChange({ starred: false, now })).toEqual({
+      starredAt: null,
+    });
+  });
+});
diff --git a/src/app/lib/portfolioUserConfig.ts b/src/app/lib/portfolioUserConfig.ts
new file mode 100644
index 00000000..37203e64
--- /dev/null
+++ b/src/app/lib/portfolioUserConfig.ts
@@ -0,0 +1,109 @@
+// Planning functions for the per-user portfolio workspace (starred portfolios
+// and personal folders — user_portfolio_config / user_portfolio_folders).
+// Pure data-in/plan-out: route handlers and server components apply the plans
+// with drizzle. See docs/design/home-redesign/ for the interaction design.
+
+export type FolderReorderPlan =
+  | { updates: Array<{ id: bigint; position: number }> }
+  | { error: string };
+
+// The drag-drop reorder PATCH sends the full ordered id list; the plan
+// renumbers every folder to its index so positions stay dense (0..n-1).
+export function planFolderReorder({
+  currentIds,
+  orderedIds,
+}: {
+  currentIds: bigint[];
+  orderedIds: bigint[];
+}): FolderReorderPlan {
+  const current = new Set(currentIds);
+  const requested = new Set(orderedIds);
+  const sameSet =
+    orderedIds.length === currentIds.length &&
+    current.size === requested.size &&
+    [...requested].every((id) => current.has(id));
+  if (!sameSet) {
+    return { error: "Folder order does not match your folders" };
+  }
+  return {
+    updates: orderedIds.map((id, index) => ({ id, position: index })),
+  };
+}
+
+// starred_at doubles as the flag (non-null = starred) and the "recently
+// starred" sort key; this is the one place that convention is written down.
+export function buildStarChange({
+  starred,
+  now,
+}: {
+  starred: boolean;
+  now: Date;
+}): { starredAt: Date | null } {
+  return { starredAt: starred ? now : null };
+}
+
+// The same-owner FK on user_portfolio_config is NO ACTION, so a folder can
+// only be deleted after its configs are unfiled — both steps must run in one
+// transaction, unfile first. This plan makes that ordering explicit.
+export function planFolderDeletion({
+  folderId,
+  configs,
+}: {
+  folderId: bigint;
+  configs: Array<{ id: bigint; folderId: bigint | null }>;
+}): { unfileConfigIds: bigint[]; deleteFolderId: bigint } {
+  return {
+    unfileConfigIds: configs
+      .filter((c) => c.folderId === folderId)
+      .map((c) => c.id),
+    deleteFolderId: folderId,
+  };
+}
+
+type ConfigRow = {
+  portfolioId: bigint;
+  folderId: bigint | null;
+  starredAt: Date | null;
+};
+
+type FolderRow = { id: bigint; name: string; position: number };
+
+// Assembles the home page's render model from the three per-user reads.
+// Generic over the portfolio payload so it doesn't care which columns the
+// page selects.
+export function groupPortfoliosForHome<P extends { id: bigint }>({
+  portfolios,
+  configs,
+  folders,
+}: {
+  portfolios: P[];
+  configs: ConfigRow[];
+  folders: FolderRow[];
+}): {
+  folders: Array<{ id: bigint; name: string; portfolios: P[] }>;
+  unfiled: P[];
+  starred: P[];
+} {
+  const configByPortfolio = new Map(configs.map((c) => [c.portfolioId, c]));
+  const folderOf = (p: P) => configByPortfolio.get(p.id)?.folderId ?? null;
+  const starredAt = (p: P) => configByPortfolio.get(p.id)?.starredAt ?? null;
+
+  // Starred float above unstarred; original relative order is otherwise kept.
+  const floatStarred = (group: P[]) =>
+    [...group].sort(
+      (a, b) => Number(starredAt(b) !== null) - Number(starredAt(a) !== null),
+    );
+
+  const orderedFolders = [...folders].sort((a, b) => a.position - b.position);
+  return {
+    folders: orderedFolders.map((f) => ({
+      id: f.id,
+      name: f.name,
+      portfolios: floatStarred(portfolios.filter((p) => folderOf(p) === f.id)),
+    })),
+    unfiled: floatStarred(portfolios.filter((p) => folderOf(p) === null)),
+    starred: portfolios
+      .filter((p) => starredAt(p) !== null)
+      .sort((a, b) => starredAt(b)!.getTime() - starredAt(a)!.getTime()),
+  };
+}