diff --git a/src/lib/__tests__/helpers.test.ts b/src/lib/__tests__/helpers.test.ts
index 55792bc..bac48cf 100644
--- a/src/lib/__tests__/helpers.test.ts
+++ b/src/lib/__tests__/helpers.test.ts
@@ -1,6 +1,13 @@
-import { describe, it, expect } from 'vitest';
+import { describe, it, expect, afterEach } from 'vitest';
 import { formatBytes, gatewayLink, gatewayUrl, truncateCid } from '../helpers';
 
+const ORIGINAL_GATEWAY = process.env.NEXT_PUBLIC_GATEWAY_URL;
+
+afterEach(() => {
+  if (ORIGINAL_GATEWAY === undefined) delete process.env.NEXT_PUBLIC_GATEWAY_URL;
+  else process.env.NEXT_PUBLIC_GATEWAY_URL = ORIGINAL_GATEWAY;
+});
+
 describe('formatBytes', () => {
   it('formats 0 as "0 B"', () => {
     expect(formatBytes(0)).toBe('0 B');
@@ -68,18 +75,43 @@ describe('formatBytes', () => {
 });
 
 describe('gatewayLink', () => {
-  it('returns correct gateway URL for valid CID', () => {
+  it('zet het CID achter het /ipfs/-segment van de gateway', () => {
     const cid = 'QmTest123';
-    expect(gatewayLink(cid)).toBe('https://ipfs.maos.dedyn.io/QmTest123');
+    expect(gatewayLink(cid)).toBe('https://ipfs.maos.dedyn.io/ipfs/QmTest123');
   });
 
   it('handles bafy CIDs', () => {
-    const cid = 'bafybeigdyrzt5xxyjaz6k3w3h3y7a7q7q7q7q7q7q7q7q7q7q7q7q7q';
-    expect(gatewayLink(cid)).toBe('https://ipfs.maos.dedyn.io/bafybeigdyrzt5xxyjaz6k3w3h3y7a7q7q7q7q7q7q7q7q7q7q7q7q7q');
+    const cid = 'bafybeigdyrzt5xxyjaz6k3w3h3y7a7q7q7q7q7q7q7q7q7q7q7q7q';
+    expect(gatewayLink(cid)).toBe('https://ipfs.maos.dedyn.io/ipfs/bafybeigdyrzt5xxyjaz6k3w3h3y7a7q7q7q7q7q7q7q7q7q7q7q7q');
   });
 
   it('handles empty string', () => {
-    expect(gatewayLink('')).toBe('https://ipfs.maos.dedyn.io/');
+    expect(gatewayLink('')).toBe('https://ipfs.maos.dedyn.io/ipfs/');
+  });
+
+  it('volgt de geconfigureerde gateway uit config.ts', () => {
+    process.env.NEXT_PUBLIC_GATEWAY_URL = 'https://gateway.example.org';
+    expect(gatewayLink('QmTest123')).toBe('https://gateway.example.org/ipfs/QmTest123');
+  });
+
+  it('verwijdert een trailing slash van de geconfigureerde gateway', () => {
+    process.env.NEXT_PUBLIC_GATEWAY_URL = 'https://gateway.example.org/';
+    expect(gatewayLink('QmTest123')).toBe('https://gateway.example.org/ipfs/QmTest123');
+  });
+
+  it('laat de gateway nooit dubbel sluiten als de CID leeg is', () => {
+    process.env.NEXT_PUBLIC_GATEWAY_URL = 'https://gateway.example.org/';
+    expect(gatewayLink('')).toBe('https://gateway.example.org/ipfs/');
+  });
+
+  it('voegt een ?filename= suffix toe voor de gateway-route', () => {
+    expect(gatewayLink('QmTest123', 'rap portaal.txt')).toBe(
+      'https://ipfs.maos.dedyn.io/ipfs/QmTest123?filename=rap%20portaal.txt',
+    );
+  });
+
+  it('laat de query-string weg als er geen filename is', () => {
+    expect(gatewayLink('QmTest123')).not.toContain('?');
   });
 });
 
diff --git a/src/lib/download.ts b/src/lib/download.ts
index 9004ce9..8328c78 100644
--- a/src/lib/download.ts
+++ b/src/lib/download.ts
@@ -2,6 +2,8 @@
  * Utility om IPFS content te downloaden als bestand.
  */
 
+import { gatewayLink } from './helpers';
+
 /**
  * Download een bestand van IPFS via de explorer/cat proxy.
  * Maakt een Blob van de response en simuleert een klik op <a download>.
@@ -34,9 +36,8 @@ export async function downloadFile(cid: string, filename?: string): Promise<void
  * Download via gateway (alternatief als proxy traag is).
  */
 export function downloadViaGateway(cid: string, filename?: string) {
-  const gateway = process.env.NEXT_PUBLIC_GATEWAY_URL || 'https://maos.dedyn.io';
   const a = document.createElement('a');
-  a.href = `${gateway}/ipfs/${cid}`;
+  a.href = gatewayLink(cid);
   a.download = filename || cid;
   a.target = '_blank';
   a.rel = 'noopener noreferrer';
diff --git a/src/lib/helpers.ts b/src/lib/helpers.ts
index d0b92b3..6091154 100644
--- a/src/lib/helpers.ts
+++ b/src/lib/helpers.ts
@@ -1,3 +1,5 @@
+import { gatewayUrl as configuredGatewayUrl } from './config';
+
 /* ── Format bytes to human-readable size ── */
 export function formatBytes(bytes: number | bigint): string {
   const b = typeof bytes === 'bigint' ? Number(bytes) : bytes;
@@ -8,9 +10,28 @@ export function formatBytes(bytes: number | bigint): string {
   return val < 10 ? val.toFixed(1) + ' ' + units[i] : Math.round(val) + ' ' + units[i];
 }
 
-/* ── Gateway link for CID ── */
-export function gatewayLink(cid: string): string {
-  return `https://ipfs.maos.dedyn.io/${cid}`;
+/* ── Gateway link voor CID ── */
+
+/**
+ * Basis-URL van de gateway, zonder trailing slash.
+ * Eén bron van waarheid: `gatewayUrl()` in `src/lib/config.ts`
+ * (env `NEXT_PUBLIC_GATEWAY_URL`, fallback `https://ipfs.maos.dedyn.io`).
+ */
+export function gatewayBaseUrl(): string {
+  return configuredGatewayUrl().replace(/\/+$/, '');
+}
+
+/**
+ * Deelbare gateway-link voor een CID.
+ *
+ * Het pad moet het `/ipfs/`-segment bevatten: de portal served content op
+ * `GET /ipfs/<cid>` (`src/app/ipfs/[cid]/route.ts`), niet op `/<cid>`.
+ * Een optionele `filename` komt als `?filename=` terecht, wat diezelfde route
+ * in `Content-Disposition` verwerkt.
+ */
+export function gatewayLink(cid: string, filename?: string): string {
+  const suffix = filename ? `?filename=${encodeURIComponent(filename)}` : '';
+  return `${gatewayBaseUrl()}/ipfs/${cid}${suffix}`;
 }
 
 /** Alias for gatewayLink — used in FilePreview */