diff --git a/apps/api/src/database/migrations/2026-06-03.ts b/apps/api/src/database/migrations/2026-06-03.ts
index a3ec329..ea69ead 100644
--- a/apps/api/src/database/migrations/2026-06-03.ts
+++ b/apps/api/src/database/migrations/2026-06-03.ts
@@ -20,12 +20,27 @@ export async function up(db: Kysely<any>): Promise<void> {
     // INDEX: ONE_ACTIVE_PRODUCT_SYNC
     await db.schema.createIndex("idx_one_active_product_sync")
         .on("product_syncs")
-        .unique()
         .column("ended_at")
+        .unique()
         .where(sql.ref("started_at"), "is not", null)
         .where("ended_at", "is", null)
         .nullsNotDistinct()
         .execute();
+
+    // TABLE: CALCULATOR_CONFIGS
+    await db.schema.createTable("calculator_configs")
+        .$call(addDefaultColumns)
+        .addColumn("parameters", "jsonb", (cb) => cb.notNull())
+        .addColumn("is_selected", "boolean", (cb) => cb.notNull())
+        .execute();
+
+    // INDEX: ONE_SELECTED_CALCULATOR_CONFIG
+    await db.schema.createIndex("idx_one_selected_calculator_config")
+        .on("calculator_configs")
+        .column("is_selected")
+        .unique()
+        .where("is_selected", "=", true)
+        .execute();
 }
 
 export async function down(db: Kysely<any>): Promise<void> {
@@ -34,4 +49,10 @@ export async function down(db: Kysely<any>): Promise<void> {
 
     // INDEX: ONE_ACTIVE_PRODUCT_SYNC
     await db.schema.dropIndex("idx_one_active_product_sync").ifExists().execute();
+
+    // TABLE: CALCULATOR_CONFIGS
+    await db.schema.dropTable("calculator_configs").ifExists().execute()
+
+    // INDEX: ONE_SELECTED_CALCULATOR_CONFIG
+    await db.schema.dropIndex("idx_one_selected_calculator_config").ifExists().execute();
 }
diff --git a/apps/api/src/server.ts b/apps/api/src/server.ts
index bc1486e..ba3a04a 100644
--- a/apps/api/src/server.ts
+++ b/apps/api/src/server.ts
@@ -96,6 +96,7 @@ export const app = new Elysia()
             status
         }, "request");
     })
+    .guard({ cookie: t.Cookie({ auth: t.Optional(t.String()) }) })
 
     .get("/", () => ({ status: "ok" }))
     .get("/health", () => ({ status: "ok" }))
@@ -115,24 +116,30 @@ export const app = new Elysia()
                 ".bladeandbrawn.com" :
                 undefined
         });
-    }, {
-        body: t.Object({ password: t.String() }),
-        cookie: t.Cookie({ auth: t.Optional(t.String()) })
-    })
+    }, { body: t.Object({ password: t.String() }) })
 
     // CALCULATOR
-    .post("/calculate", async ({ body }) => {
-        return { levels: levelCalculator.calculate(body.player, body.activityPerformances) };
-    }, {
-        body: t.Object({
-            player: PlayerSchema,
-            activityPerformances: t.Array(ActivityPerformanceSchema)
-        }),
-    })
+    .group("/calculator",
+        (app) => app
+            .post("/calculate", async ({ body }) => {
+                return { levels: levelCalculator.calculate(body.player, body.activityPerformances) };
+            }, {
+                body: t.Object({
+                    player: PlayerSchema,
+                    activityPerformances: t.Array(ActivityPerformanceSchema)
+                }),
+            })
+            .resolve(async ({ jwt, cookie: { auth } }) => {
+                const token = auth.value && await jwt.verify(auth.value);
+                if (!token || !token.sessionId) throw status(401, "Unauthorized");
+                return { sessionId: token.sessionId.toString() };
+            })
+            .post("/config", () => { })
+            .get("/config", () => { })
+    )
 
     // COMMERCE
     .group("/products",
-        { cookie: t.Cookie({ auth: t.Optional(t.String()) }) },
         (app) => app
             .resolve(async ({ jwt, cookie: { auth } }) => {
                 const token = auth.value && await jwt.verify(auth.value);
diff --git a/apps/api/src/services/calculator.ts b/apps/api/src/services/calculator.ts
new file mode 100644
index 0000000..398290e
--- /dev/null
+++ b/apps/api/src/services/calculator.ts
@@ -0,0 +1,3 @@
+export class CalculatorService {
+
+}