diff --git a/packages/api/src/__tests__/org-unit-support.test.ts b/packages/api/src/__tests__/org-unit-support.test.ts
new file mode 100644
index 0000000..8a0c1d0
--- /dev/null
+++ b/packages/api/src/__tests__/org-unit-support.test.ts
@@ -0,0 +1,121 @@
+import { TRPCError } from "@trpc/server";
+import { describe, expect, it, vi } from "vitest";
+import {
+  assertOrgUnitParentLevel,
+  buildOrgUnitCreateData,
+  buildOrgUnitListWhere,
+  buildOrgUnitTree,
+  buildOrgUnitUpdateData,
+  findOrgUnitByIdentifier,
+} from "../router/org-unit-support.js";
+
+describe("org-unit support", () => {
+  it("builds list filters", () => {
+    expect(buildOrgUnitListWhere({
+      level: 5,
+      parentId: "root",
+      isActive: true,
+    })).toEqual({
+      level: 5,
+      parentId: "root",
+      isActive: true,
+    });
+  });
+
+  it("builds a sorted org-unit tree", () => {
+    expect(buildOrgUnitTree([
+      {
+        id: "child_b",
+        name: "Beta",
+        shortName: "BET",
+        level: 6,
+        parentId: "root",
+        sortOrder: 20,
+        isActive: true,
+        createdAt: new Date("2026-03-01T00:00:00.000Z"),
+        updatedAt: new Date("2026-03-01T00:00:00.000Z"),
+      },
+      {
+        id: "root",
+        name: "Delivery",
+        shortName: "DEL",
+        level: 5,
+        parentId: null,
+        sortOrder: 10,
+        isActive: true,
+        createdAt: new Date("2026-03-01T00:00:00.000Z"),
+        updatedAt: new Date("2026-03-01T00:00:00.000Z"),
+      },
+      {
+        id: "child_a",
+        name: "Alpha",
+        shortName: "ALP",
+        level: 6,
+        parentId: "root",
+        sortOrder: 20,
+        isActive: true,
+        createdAt: new Date("2026-03-01T00:00:00.000Z"),
+        updatedAt: new Date("2026-03-01T00:00:00.000Z"),
+      },
+    ])).toEqual([
+      expect.objectContaining({
+        id: "root",
+        children: [
+          expect.objectContaining({ id: "child_a", children: [] }),
+          expect.objectContaining({ id: "child_b", children: [] }),
+        ],
+      }),
+    ]);
+  });
+
+  it("resolves org units by short name fallback", async () => {
+    const db = {
+      orgUnit: {
+        findUnique: vi.fn().mockResolvedValue(null),
+        findFirst: vi.fn()
+          .mockResolvedValueOnce(null)
+          .mockResolvedValueOnce({ id: "ou_1", shortName: "DEL" }),
+      },
+    } as never;
+
+    const result = await findOrgUnitByIdentifier<{ id: string; shortName: string }>(
+      db,
+      " del ",
+      { select: { id: true, shortName: true } },
+    );
+
+    expect(result).toEqual({ id: "ou_1", shortName: "DEL" });
+    expect(db.orgUnit.findFirst).toHaveBeenNthCalledWith(2, {
+      where: { shortName: { equals: "del", mode: "insensitive" } },
+      select: { id: true, shortName: true },
+    });
+  });
+
+  it("rejects invalid parent/child level combinations", () => {
+    expect(() => assertOrgUnitParentLevel({ level: 6 }, 6)).toThrow(TRPCError);
+  });
+
+  it("builds create and sparse update payloads", () => {
+    expect(buildOrgUnitCreateData({
+      name: "Delivery",
+      shortName: "DEL",
+      level: 5,
+      parentId: "root",
+      sortOrder: 10,
+    })).toEqual({
+      name: "Delivery",
+      shortName: "DEL",
+      level: 5,
+      parentId: "root",
+      sortOrder: 10,
+    });
+
+    expect(buildOrgUnitUpdateData({
+      shortName: null,
+      isActive: false,
+    })).toEqual({
+      shortName: null,
+      isActive: false,
+    });
+  });
+});
diff --git a/packages/api/src/router/org-unit-support.ts b/packages/api/src/router/org-unit-support.ts
new file mode 100644
index 0000000..820bcbe
--- /dev/null
+++ b/packages/api/src/router/org-unit-support.ts
@@ -0,0 +1,138 @@
+import type { Prisma, PrismaClient } from "@capakraken/db";
+import { CreateOrgUnitSchema, UpdateOrgUnitSchema, type OrgUnitTree } from "@capakraken/shared";
+import { TRPCError } from "@trpc/server";
+import { z } from "zod";
+
+type OrgUnitDb = Pick<PrismaClient, "orgUnit">;
+
+type OrgUnitListInput = {
+  level?: number | undefined;
+  parentId?: string | undefined;
+  isActive?: boolean | undefined;
+};
+
+type OrgUnitTreeNode = {
+  id: string;
+  name: string;
+  shortName: string | null;
+  level: number;
+  parentId: string | null;
+  sortOrder: number;
+  isActive: boolean;
+  createdAt: Date;
+  updatedAt: Date;
+};
+
+type ParentOrgUnitRecord = {
+  level: number;
+};
+
+type CreateOrgUnitInput = z.infer<typeof CreateOrgUnitSchema>;
+type UpdateOrgUnitInput = z.infer<typeof UpdateOrgUnitSchema>;
+
+export function buildOrgUnitListWhere(
+  input: OrgUnitListInput,
+): Prisma.OrgUnitWhereInput {
+  return {
+    ...(input.level !== undefined ? { level: input.level } : {}),
+    ...(input.parentId !== undefined ? { parentId: input.parentId } : {}),
+    ...(input.isActive !== undefined ? { isActive: input.isActive } : {}),
+  };
+}
+
+export function buildOrgUnitTree(
+  flatItems: OrgUnitTreeNode[],
+  parentId: string | null = null,
+): OrgUnitTree[] {
+  return flatItems
+    .filter((item) => item.parentId === parentId)
+    .sort((a, b) => a.sortOrder - b.sortOrder || a.name.localeCompare(b.name))
+    .map((item) => ({
+      ...item,
+      children: buildOrgUnitTree(flatItems, item.id),
+    }));
+}
+
+export async function findOrgUnitByIdentifier<TOrgUnit>(
+  db: OrgUnitDb,
+  identifier: string,
+  extraArgs: Record<string, unknown>,
+): Promise<TOrgUnit> {
+  const normalizedIdentifier = identifier.trim();
+
+  let unit = await db.orgUnit.findUnique({
+    where: { id: normalizedIdentifier },
+    ...extraArgs,
+  }) as TOrgUnit | null;
+
+  if (!unit) {
+    unit = await db.orgUnit.findFirst({
+      where: { name: { equals: normalizedIdentifier, mode: "insensitive" } },
+      ...extraArgs,
+    }) as TOrgUnit | null;
+  }
+
+  if (!unit) {
+    unit = await db.orgUnit.findFirst({
+      where: { shortName: { equals: normalizedIdentifier, mode: "insensitive" } },
+      ...extraArgs,
+    }) as TOrgUnit | null;
+  }
+
+  if (!unit) {
+    unit = await db.orgUnit.findFirst({
+      where: {
+        OR: [
+          { name: { contains: normalizedIdentifier, mode: "insensitive" } },
+          { shortName: { contains: normalizedIdentifier, mode: "insensitive" } },
+        ],
+      },
+      ...extraArgs,
+    }) as TOrgUnit | null;
+  }
+
+  if (!unit) {
+    throw new TRPCError({
+      code: "NOT_FOUND",
+      message: `Org unit not found: ${normalizedIdentifier}`,
+    });
+  }
+
+  return unit;
+}
+
+export function assertOrgUnitParentLevel(
+  parent: ParentOrgUnitRecord,
+  childLevel: number,
+): void {
+  if (parent.level >= childLevel) {
+    throw new TRPCError({
+      code: "BAD_REQUEST",
+      message: `Child level (${childLevel}) must be greater than parent level (${parent.level})`,
+    });
+  }
+}
+
+export function buildOrgUnitCreateData(
+  input: CreateOrgUnitInput,
+): Prisma.OrgUnitUncheckedCreateInput {
+  return {
+    name: input.name,
+    ...(input.shortName !== undefined ? { shortName: input.shortName } : {}),
+    level: input.level,
+    ...(input.parentId ? { parentId: input.parentId } : {}),
+    sortOrder: input.sortOrder,
+  };
+}
+
+export function buildOrgUnitUpdateData(
+  input: UpdateOrgUnitInput,
+): Prisma.OrgUnitUncheckedUpdateInput {
+  return {
+    ...(input.name !== undefined ? { name: input.name } : {}),
+    ...(input.shortName !== undefined ? { shortName: input.shortName } : {}),
+    ...(input.sortOrder !== undefined ? { sortOrder: input.sortOrder } : {}),
+    ...(input.isActive !== undefined ? { isActive: input.isActive } : {}),
+    ...(input.parentId !== undefined ? { parentId: input.parentId } : {}),
+  };
+}
diff --git a/packages/api/src/router/org-unit.ts b/packages/api/src/router/org-unit.ts
index 341f8c7..8584bed 100644
--- a/packages/api/src/router/org-unit.ts
+++ b/packages/api/src/router/org-unit.ts
@@ -1,5 +1,4 @@
 import { CreateOrgUnitSchema, UpdateOrgUnitSchema } from "@capakraken/shared";
-import { TRPCError } from "@trpc/server";
 import { z } from "zod";
 import { findUniqueOrThrow } from "../db/helpers.js";
 import { createAuditEntry } from "../lib/audit.js";
@@ -9,30 +8,30 @@ import {
   protectedProcedure,
   resourceOverviewProcedure,
 } from "../trpc.js";
+import {
+  assertOrgUnitParentLevel,
+  buildOrgUnitCreateData,
+  buildOrgUnitListWhere,
+  buildOrgUnitTree,
+  buildOrgUnitUpdateData,
+  findOrgUnitByIdentifier,
+} from "./org-unit-support.js";
 
-import type { OrgUnitTree } from "@capakraken/shared";
-
-interface FlatOrgUnit {
+type OrgUnitIdentifierReadModel = {
   id: string;
   name: string;
   shortName: string | null;
   level: number;
+  isActive: boolean;
+};
+
+type OrgUnitDetailReadModel = OrgUnitIdentifierReadModel & {
   parentId: string | null;
   sortOrder: number;
-  isActive: boolean;
   createdAt: Date;
   updatedAt: Date;
-}
-
-function buildTree(flatItems: FlatOrgUnit[], parentId: string | null = null): OrgUnitTree[] {
-  return flatItems
-    .filter((item) => item.parentId === parentId)
-    .sort((a, b) => a.sortOrder - b.sortOrder || a.name.localeCompare(b.name))
-    .map((item) => ({
-      ...item,
-      children: buildTree(flatItems, item.id),
-    }));
-}
+  _count: { resources: number };
+};
 
 export const orgUnitRouter = createTRPCRouter({
   list: resourceOverviewProcedure
@@ -45,11 +44,7 @@ export const orgUnitRouter = createTRPCRouter({
     )
     .query(async ({ ctx, input }) => {
       return ctx.db.orgUnit.findMany({
-        where: {
-          ...(input?.level !== undefined ? { level: input.level } : {}),
-          ...(input?.parentId !== undefined ? { parentId: input.parentId } : {}),
-          ...(input?.isActive !== undefined ? { isActive: input.isActive } : {}),
-        },
+        where: buildOrgUnitListWhere(input ?? {}),
         orderBy: [{ level: "asc" }, { sortOrder: "asc" }, { name: "asc" }],
       });
     }),
@@ -58,12 +53,10 @@ export const orgUnitRouter = createTRPCRouter({
     .input(z.object({ isActive: z.boolean().optional() }).optional())
     .query(async ({ ctx, input }) => {
       const all = await ctx.db.orgUnit.findMany({
-        where: {
-          ...(input?.isActive !== undefined ? { isActive: input.isActive } : {}),
-        },
+        where: buildOrgUnitListWhere({ isActive: input?.isActive }),
         orderBy: [{ sortOrder: "asc" }, { name: "asc" }],
       });
-      return buildTree(all);
+      return buildOrgUnitTree(all);
     }),
 
   getById: resourceOverviewProcedure
@@ -86,93 +79,23 @@ export const orgUnitRouter = createTRPCRouter({
   resolveByIdentifier: protectedProcedure
     .input(z.object({ identifier: z.string().trim().min(1) }))
     .query(async ({ ctx, input }) => {
-      const identifier = input.identifier.trim();
-      const select = {
-        id: true,
-        name: true,
-        shortName: true,
-        level: true,
-        isActive: true,
-      } as const;
-
-      let unit = await ctx.db.orgUnit.findUnique({
-        where: { id: identifier },
-        select,
+      return findOrgUnitByIdentifier<OrgUnitIdentifierReadModel>(ctx.db, input.identifier, {
+        select: {
+          id: true,
+          name: true,
+          shortName: true,
+          level: true,
+          isActive: true,
+        },
       });
-
-      if (!unit) {
-        unit = await ctx.db.orgUnit.findFirst({
-          where: { name: { equals: identifier, mode: "insensitive" } },
-          select,
-        });
-      }
-
-      if (!unit) {
-        unit = await ctx.db.orgUnit.findFirst({
-          where: { shortName: { equals: identifier, mode: "insensitive" } },
-          select,
-        });
-      }
-
-      if (!unit) {
-        unit = await ctx.db.orgUnit.findFirst({
-          where: {
-            OR: [
-              { name: { contains: identifier, mode: "insensitive" } },
-              { shortName: { contains: identifier, mode: "insensitive" } },
-            ],
-          },
-          select,
-        });
-      }
-
-      if (!unit) {
-        throw new TRPCError({ code: "NOT_FOUND", message: `Org unit not found: ${identifier}` });
-      }
-
-      return unit;
     }),
 
   getByIdentifier: resourceOverviewProcedure
     .input(z.object({ identifier: z.string().trim().min(1) }))
     .query(async ({ ctx, input }) => {
-      const identifier = input.identifier.trim();
-      let unit = await ctx.db.orgUnit.findUnique({
-        where: { id: identifier },
+      return findOrgUnitByIdentifier<OrgUnitDetailReadModel>(ctx.db, input.identifier, {
         include: { _count: { select: { resources: true } } },
       });
-
-      if (!unit) {
-        unit = await ctx.db.orgUnit.findFirst({
-          where: { name: { equals: identifier, mode: "insensitive" } },
-          include: { _count: { select: { resources: true } } },
-        });
-      }
-
-      if (!unit) {
-        unit = await ctx.db.orgUnit.findFirst({
-          where: { shortName: { equals: identifier, mode: "insensitive" } },
-          include: { _count: { select: { resources: true } } },
-        });
-      }
-
-      if (!unit) {
-        unit = await ctx.db.orgUnit.findFirst({
-          where: {
-            OR: [
-              { name: { contains: identifier, mode: "insensitive" } },
-              { shortName: { contains: identifier, mode: "insensitive" } },
-            ],
-          },
-          include: { _count: { select: { resources: true } } },
-        });
-      }
-
-      if (!unit) {
-        throw new TRPCError({ code: "NOT_FOUND", message: `Org unit not found: ${identifier}` });
-      }
-
-      return unit;
     }),
 
   create: adminProcedure
@@ -183,22 +106,11 @@ export const orgUnitRouter = createTRPCRouter({
           ctx.db.orgUnit.findUnique({ where: { id: input.parentId } }),
           "Parent org unit",
         );
-        if (parent.level >= input.level) {
-          throw new TRPCError({
-            code: "BAD_REQUEST",
-            message: `Child level (${input.level}) must be greater than parent level (${parent.level})`,
-          });
-        }
+        assertOrgUnitParentLevel(parent, input.level);
       }
 
       const created = await ctx.db.orgUnit.create({
-        data: {
-          name: input.name,
-          ...(input.shortName !== undefined ? { shortName: input.shortName } : {}),
-          level: input.level,
-          ...(input.parentId ? { parentId: input.parentId } : {}),
-          sortOrder: input.sortOrder,
-        },
+        data: buildOrgUnitCreateData(input),
       });
 
       void createAuditEntry({
@@ -227,13 +139,7 @@ export const orgUnitRouter = createTRPCRouter({
 
       const updated = await ctx.db.orgUnit.update({
         where: { id: input.id },
-        data: {
-          ...(input.data.name !== undefined ? { name: input.data.name } : {}),
-          ...(input.data.shortName !== undefined ? { shortName: input.data.shortName } : {}),
-          ...(input.data.sortOrder !== undefined ? { sortOrder: input.data.sortOrder } : {}),
-          ...(input.data.isActive !== undefined ? { isActive: input.data.isActive } : {}),
-          ...(input.data.parentId !== undefined ? { parentId: input.data.parentId } : {}),
-        },
+        data: buildOrgUnitUpdateData(input.data),
       });
 
       void createAuditEntry({