diff --git a/src/app/api/v1/stock-purchases/[id]/attachments/[filename]/route.test.ts b/src/app/api/v1/stock-purchases/[id]/attachments/[filename]/route.test.ts
new file mode 100644
index 0000000..640180d
--- /dev/null
+++ b/src/app/api/v1/stock-purchases/[id]/attachments/[filename]/route.test.ts
@@ -0,0 +1,63 @@
+// @vitest-environment node
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+
+vi.mock("@/lib/server/stock-purchases-service", () => ({
+  removeStockPurchaseAttachment: vi.fn(),
+}));
+
+import { DELETE } from "./route";
+import { removeStockPurchaseAttachment } from "@/lib/server/stock-purchases-service";
+
+const rmMock = removeStockPurchaseAttachment as unknown as ReturnType<
+  typeof vi.fn
+>;
+
+describe("DELETE /api/v1/stock-purchases/[id]/attachments/[filename]", () => {
+  beforeEach(() => {
+    rmMock.mockReset();
+  });
+  afterEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it("returns 200 + remaining attachments on success", async () => {
+    rmMock.mockResolvedValueOnce({ attachments: ["keep.pdf"] });
+    const res = await DELETE(
+      new Request("http://localhost/api/v1/stock-purchases/sp-1/attachments/drop.pdf", {
+        method: "DELETE",
+      }),
+      { params: Promise.resolve({ id: "sp-1", filename: "drop.pdf" }) },
+    );
+    expect(res.status).toBe(200);
+    const body = await res.json();
+    expect(body).toEqual({ ok: true, attachments: ["keep.pdf"] });
+    expect(rmMock).toHaveBeenCalledWith({
+      purchaseId: "sp-1",
+      token: "drop.pdf",
+    });
+  });
+
+  it("returns 404 when the token is not in the array", async () => {
+    rmMock.mockRejectedValueOnce(new Error("Attachment not found: nope.pdf"));
+    const res = await DELETE(
+      new Request("http://localhost/api/v1/stock-purchases/sp-1/attachments/nope.pdf", {
+        method: "DELETE",
+      }),
+      { params: Promise.resolve({ id: "sp-1", filename: "nope.pdf" }) },
+    );
+    expect(res.status).toBe(404);
+    const body = await res.json();
+    expect(body.error).toMatch(/not found/i);
+  });
+
+  it("returns 500 on other service errors", async () => {
+    rmMock.mockRejectedValueOnce(new Error("PB unreachable"));
+    const res = await DELETE(
+      new Request("http://localhost/api/v1/stock-purchases/sp-1/attachments/drop.pdf", {
+        method: "DELETE",
+      }),
+      { params: Promise.resolve({ id: "sp-1", filename: "drop.pdf" }) },
+    );
+    expect(res.status).toBe(500);
+  });
+});
diff --git a/src/app/api/v1/stock-purchases/[id]/attachments/[filename]/route.ts b/src/app/api/v1/stock-purchases/[id]/attachments/[filename]/route.ts
new file mode 100644
index 0000000..102a743
--- /dev/null
+++ b/src/app/api/v1/stock-purchases/[id]/attachments/[filename]/route.ts
@@ -0,0 +1,41 @@
+import { NextRequest, NextResponse } from "next/server";
+import { removeStockPurchaseAttachment } from "@/lib/server/stock-purchases-service";
+
+/**
+ * DELETE /api/v1/stock-purchases/[id]/attachments/[filename]
+ *
+ * Remove a single additional attachment token from a stock purchase.
+ * Mirrors `/api/v1/purchase-orders/[id]/attachments/[filename]`. The
+ * `filename` segment is the PB-stored token (the same string that
+ * appears in `additional_attachments[]`), not the operator's original
+ * filename. PB doesn't expose a per-file delete on a multi-file field
+ * via the SDK, so the underlying helper filters the array client-side
+ * and writes the rest back; the on-disk file is left in place (same
+ * limitation as the PO route).
+ *
+ * Response:
+ *   200 — { ok: true, attachments: [remaining tokens] }
+ *   404 — { error: "Attachment not found: <token>" }
+ *   500 — { error } on PB or service failure
+ */
+
+export const runtime = "nodejs";
+export const dynamic = "force-dynamic";
+
+export async function DELETE(
+  _req: NextRequest,
+  { params }: { params: Promise<{ id: string; filename: string }> },
+) {
+  const { id: purchaseId, filename: token } = await params;
+  try {
+    const { attachments } = await removeStockPurchaseAttachment({
+      purchaseId,
+      token,
+    });
+    return NextResponse.json({ ok: true, attachments }, { status: 200 });
+  } catch (err) {
+    const msg = err instanceof Error ? err.message : "Delete failed";
+    const status = /not found/i.test(msg) ? 404 : 500;
+    return NextResponse.json({ error: msg }, { status });
+  }
+}