diff --git a/app/components/app-menu/settings/nostr.gjs b/app/components/app-menu/settings/nostr.gjs
index 29c7dc0..7612f9e 100644
--- a/app/components/app-menu/settings/nostr.gjs
+++ b/app/components/app-menu/settings/nostr.gjs
@@ -5,7 +5,11 @@ import { tracked } from '@glimmer/tracking';
 import { service } from '@ember/service';
 import { fn } from '@ember/helper';
 import Icon from '#components/icon';
-import { normalizeRelayUrl } from '../../../utils/nostr';
+import {
+  excludeRequiredRelays,
+  mergeRequiredRelays,
+  normalizeRelayUrl,
+} from '../../../utils/nostr';
 
 const stripProtocol = (url) => (url ? url.replace(/^wss?:\/\//, '') : '');
 
@@ -17,6 +21,74 @@ export default class AppMenuSettingsNostr extends Component {
   @tracked newReadRelay = '';
   @tracked newWriteRelay = '';
 
+  get customReadRelays() {
+    return excludeRequiredRelays(
+      this.settings.nostrReadRelays || [],
+      this.nostrData.requiredReadRelays
+    );
+  }
+
+  get customWriteRelays() {
+    return excludeRequiredRelays(
+      this.settings.nostrWriteRelays || [],
+      this.nostrData.requiredWriteRelays
+    );
+  }
+
+  get readRelayExclusions() {
+    return this.settings.nostrReadRelayExclusions || [];
+  }
+
+  get writeRelayExclusions() {
+    return this.settings.nostrWriteRelayExclusions || [];
+  }
+
+  get requiredReadRelaySet() {
+    return new Set(this.nostrData.requiredReadRelays.filter(Boolean));
+  }
+
+  get requiredWriteRelaySet() {
+    return new Set(this.nostrData.requiredWriteRelays.filter(Boolean));
+  }
+
+  get mailboxReadRelaySet() {
+    return new Set(this.nostrData.mailboxReadRelays);
+  }
+
+  get mailboxWriteRelaySet() {
+    return new Set(this.nostrData.mailboxWriteRelays);
+  }
+
+  get hasReadOverrides() {
+    return (
+      this.customReadRelays.length > 0 || this.readRelayExclusions.length > 0
+    );
+  }
+
+  get hasWriteOverrides() {
+    return (
+      this.customWriteRelays.length > 0 || this.writeRelayExclusions.length > 0
+    );
+  }
+
+  get readRelaysForDisplay() {
+    return this.nostrData.activeReadRelays.map((url) => {
+      return {
+        url,
+        isRequired: this.requiredReadRelaySet.has(url),
+      };
+    });
+  }
+
+  get writeRelaysForDisplay() {
+    return this.nostrData.activeWriteRelays.map((url) => {
+      return {
+        url,
+        isRequired: this.requiredWriteRelaySet.has(url),
+      };
+    });
+  }
+
   @action
   updateNewReadRelay(event) {
     this.newReadRelay = event.target.value;
@@ -32,19 +104,51 @@ export default class AppMenuSettingsNostr extends Component {
     const url = normalizeRelayUrl(this.newReadRelay);
     if (!url) return;
 
-    const current =
-      this.settings.nostrReadRelays || this.nostrData.defaultReadRelays;
-    const set = new Set([...current, url]);
-    this.settings.update('nostrReadRelays', Array.from(set));
+    const merged = mergeRequiredRelays(this.nostrData.requiredReadRelays, [
+      ...this.customReadRelays,
+      url,
+    ]);
+    const custom = excludeRequiredRelays(
+      merged,
+      this.nostrData.requiredReadRelays
+    );
+
+    const readExclusions = this.readRelayExclusions.filter((relay) => {
+      return normalizeRelayUrl(relay) !== url;
+    });
+
+    this.settings.update('nostrReadRelays', custom.length > 0 ? custom : null);
+    this.settings.update(
+      'nostrReadRelayExclusions',
+      readExclusions.length > 0 ? readExclusions : null
+    );
     this.newReadRelay = '';
   }
 
   @action
   removeReadRelay(url) {
-    const current =
-      this.settings.nostrReadRelays || this.nostrData.defaultReadRelays;
-    const filtered = current.filter((r) => r !== url);
-    this.settings.update('nostrReadRelays', filtered);
+    if (this.requiredReadRelaySet.has(url)) {
+      return;
+    }
+
+    const normalizedUrl = normalizeRelayUrl(url);
+
+    const remainingCustom = this.customReadRelays.filter((relay) => {
+      return normalizeRelayUrl(relay) !== normalizedUrl;
+    });
+
+    const nextExclusions = this.mailboxReadRelaySet.has(normalizedUrl)
+      ? Array.from(new Set([...this.readRelayExclusions, normalizedUrl]))
+      : this.readRelayExclusions;
+
+    this.settings.update(
+      'nostrReadRelays',
+      remainingCustom.length > 0 ? remainingCustom : null
+    );
+    this.settings.update(
+      'nostrReadRelayExclusions',
+      nextExclusions.length > 0 ? nextExclusions : null
+    );
   }
 
   @action
@@ -64,6 +168,7 @@ export default class AppMenuSettingsNostr extends Component {
   @action
   resetReadRelays() {
     this.settings.update('nostrReadRelays', null);
+    this.settings.update('nostrReadRelayExclusions', null);
   }
 
   @action
@@ -71,24 +176,57 @@ export default class AppMenuSettingsNostr extends Component {
     const url = normalizeRelayUrl(this.newWriteRelay);
     if (!url) return;
 
-    const current =
-      this.settings.nostrWriteRelays || this.nostrData.defaultWriteRelays;
-    const set = new Set([...current, url]);
-    this.settings.update('nostrWriteRelays', Array.from(set));
+    const merged = mergeRequiredRelays(this.nostrData.requiredWriteRelays, [
+      ...this.customWriteRelays,
+      url,
+    ]);
+    const custom = excludeRequiredRelays(
+      merged,
+      this.nostrData.requiredWriteRelays
+    );
+
+    const writeExclusions = this.writeRelayExclusions.filter((relay) => {
+      return normalizeRelayUrl(relay) !== url;
+    });
+
+    this.settings.update('nostrWriteRelays', custom.length > 0 ? custom : null);
+    this.settings.update(
+      'nostrWriteRelayExclusions',
+      writeExclusions.length > 0 ? writeExclusions : null
+    );
     this.newWriteRelay = '';
   }
 
   @action
   removeWriteRelay(url) {
-    const current =
-      this.settings.nostrWriteRelays || this.nostrData.defaultWriteRelays;
-    const filtered = current.filter((r) => r !== url);
-    this.settings.update('nostrWriteRelays', filtered);
+    if (this.requiredWriteRelaySet.has(url)) {
+      return;
+    }
+
+    const normalizedUrl = normalizeRelayUrl(url);
+
+    const remainingCustom = this.customWriteRelays.filter((relay) => {
+      return normalizeRelayUrl(relay) !== normalizedUrl;
+    });
+
+    const nextExclusions = this.mailboxWriteRelaySet.has(normalizedUrl)
+      ? Array.from(new Set([...this.writeRelayExclusions, normalizedUrl]))
+      : this.writeRelayExclusions;
+
+    this.settings.update(
+      'nostrWriteRelays',
+      remainingCustom.length > 0 ? remainingCustom : null
+    );
+    this.settings.update(
+      'nostrWriteRelayExclusions',
+      nextExclusions.length > 0 ? nextExclusions : null
+    );
   }
 
   @action
   resetWriteRelays() {
     this.settings.update('nostrWriteRelays', null);
+    this.settings.update('nostrWriteRelayExclusions', null);
   }
 
   @action
@@ -112,18 +250,20 @@ export default class AppMenuSettingsNostr extends Component {
         <div class="form-group">
           <label for="new-read-relay">Read Relays</label>
           <ul class="relay-list">
-            {{#each this.nostrData.activeReadRelays as |relay|}}
+            {{#each this.readRelaysForDisplay as |relay|}}
               <li>
-                <span>{{stripProtocol relay}}</span>
-                <button
-                  type="button"
-                  class="btn-remove-relay"
-                  title="Remove relay"
-                  aria-label="Remove"
-                  {{on "click" (fn this.removeReadRelay relay)}}
-                >
-                  <Icon @name="x" @size={{14}} @color="currentColor" />
-                </button>
+                <span>{{stripProtocol relay.url}}</span>
+                {{#unless relay.isRequired}}
+                  <button
+                    type="button"
+                    class="btn-remove-relay"
+                    title="Remove relay"
+                    aria-label="Remove"
+                    {{on "click" (fn this.removeReadRelay relay.url)}}
+                  >
+                    <Icon @name="x" @size={{14}} @color="currentColor" />
+                  </button>
+                {{/unless}}
               </li>
             {{/each}}
           </ul>
@@ -143,7 +283,7 @@ export default class AppMenuSettingsNostr extends Component {
               {{on "click" this.addReadRelay}}
             >Add</button>
           </div>
-          {{#if this.settings.nostrReadRelays}}
+          {{#if this.hasReadOverrides}}
             <button
               type="button"
               class="btn-link reset-relays"
@@ -157,18 +297,20 @@ export default class AppMenuSettingsNostr extends Component {
         <div class="form-group">
           <label for="new-write-relay">Write Relays</label>
           <ul class="relay-list">
-            {{#each this.nostrData.activeWriteRelays as |relay|}}
+            {{#each this.writeRelaysForDisplay as |relay|}}
               <li>
-                <span>{{stripProtocol relay}}</span>
-                <button
-                  type="button"
-                  class="btn-remove-relay"
-                  title="Remove relay"
-                  aria-label="Remove"
-                  {{on "click" (fn this.removeWriteRelay relay)}}
-                >
-                  <Icon @name="x" @size={{14}} @color="currentColor" />
-                </button>
+                <span>{{stripProtocol relay.url}}</span>
+                {{#unless relay.isRequired}}
+                  <button
+                    type="button"
+                    class="btn-remove-relay"
+                    title="Remove relay"
+                    aria-label="Remove"
+                    {{on "click" (fn this.removeWriteRelay relay.url)}}
+                  >
+                    <Icon @name="x" @size={{14}} @color="currentColor" />
+                  </button>
+                {{/unless}}
               </li>
             {{/each}}
           </ul>
@@ -188,7 +330,7 @@ export default class AppMenuSettingsNostr extends Component {
               {{on "click" this.addWriteRelay}}
             >Add</button>
           </div>
-          {{#if this.settings.nostrWriteRelays}}
+          {{#if this.hasWriteOverrides}}
             <button
               type="button"
               class="btn-link reset-relays"
diff --git a/app/services/nostr-data.js b/app/services/nostr-data.js
index c1fe03d..ea8ab9c 100644
--- a/app/services/nostr-data.js
+++ b/app/services/nostr-data.js
@@ -6,7 +6,12 @@ import { MailboxesModel } from 'applesauce-core/models/mailboxes';
 import { npubEncode } from 'applesauce-core/helpers/pointers';
 import { persistEventsToCache } from 'applesauce-core/helpers/event-cache';
 import { NostrIDB, openDB } from 'nostr-idb';
-import { normalizeRelayUrl } from '../utils/nostr';
+import {
+  excludeRequiredRelays,
+  mergeRequiredRelays,
+  normalizeRelayUrl,
+  uniqNormalizedRelays,
+} from '../utils/nostr';
 import { getGeohashPrefixesInBbox } from '../utils/geohash-coverage';
 
 const DIRECTORY_RELAYS = [
@@ -83,43 +88,62 @@ export default class NostrDataService extends Service {
     });
   }
 
-  get defaultReadRelays() {
-    const mailboxes = (this.mailboxes?.inboxes || [])
-      .map(normalizeRelayUrl)
-      .filter(Boolean);
-    const defaults = DEFAULT_READ_RELAYS.map(normalizeRelayUrl).filter(Boolean);
-    return Array.from(new Set([...defaults, ...mailboxes]));
+  get requiredReadRelays() {
+    return DEFAULT_READ_RELAYS;
   }
 
-  get defaultWriteRelays() {
-    const mailboxes = (this.mailboxes?.outboxes || [])
+  get requiredWriteRelays() {
+    return DEFAULT_WRITE_RELAYS;
+  }
+
+  get mailboxReadRelays() {
+    return (this.mailboxes?.inboxes || [])
       .map(normalizeRelayUrl)
       .filter(Boolean);
-    const defaults =
-      DEFAULT_WRITE_RELAYS.map(normalizeRelayUrl).filter(Boolean);
-    return Array.from(new Set([...defaults, ...mailboxes]));
+  }
+
+  get mailboxWriteRelays() {
+    return (this.mailboxes?.outboxes || [])
+      .map(normalizeRelayUrl)
+      .filter(Boolean);
+  }
+
+  get configuredReadRelays() {
+    const configured = uniqNormalizedRelays([
+      ...this.mailboxReadRelays,
+      ...(this.settings.nostrReadRelays || []),
+    ]);
+
+    return excludeRequiredRelays(
+      configured,
+      this.settings.nostrReadRelayExclusions || []
+    );
+  }
+
+  get configuredWriteRelays() {
+    const configured = uniqNormalizedRelays([
+      ...this.mailboxWriteRelays,
+      ...(this.settings.nostrWriteRelays || []),
+    ]);
+
+    return excludeRequiredRelays(
+      configured,
+      this.settings.nostrWriteRelayExclusions || []
+    );
   }
 
   get activeReadRelays() {
-    if (this.settings.nostrReadRelays) {
-      return Array.from(
-        new Set(
-          this.settings.nostrReadRelays.map(normalizeRelayUrl).filter(Boolean)
-        )
-      );
-    }
-    return this.defaultReadRelays;
+    return mergeRequiredRelays(
+      this.requiredReadRelays,
+      this.configuredReadRelays
+    );
   }
 
   get activeWriteRelays() {
-    if (this.settings.nostrWriteRelays) {
-      return Array.from(
-        new Set(
-          this.settings.nostrWriteRelays.map(normalizeRelayUrl).filter(Boolean)
-        )
-      );
-    }
-    return this.defaultWriteRelays;
+    return mergeRequiredRelays(
+      this.requiredWriteRelays,
+      this.configuredWriteRelays
+    );
   }
 
   async loadPlacesInBounds(bbox) {
diff --git a/app/services/settings.js b/app/services/settings.js
index a198166..4139245 100644
--- a/app/services/settings.js
+++ b/app/services/settings.js
@@ -9,6 +9,8 @@ const DEFAULT_SETTINGS = {
   nostrPhotoFallbackUploads: false,
   nostrReadRelays: null,
   nostrWriteRelays: null,
+  nostrReadRelayExclusions: null,
+  nostrWriteRelayExclusions: null,
   experimentalEnablePhotoDeletion: false,
 };
 
@@ -21,6 +23,9 @@ export default class SettingsService extends Service {
     DEFAULT_SETTINGS.nostrPhotoFallbackUploads;
   @tracked nostrReadRelays = DEFAULT_SETTINGS.nostrReadRelays;
   @tracked nostrWriteRelays = DEFAULT_SETTINGS.nostrWriteRelays;
+  @tracked nostrReadRelayExclusions = DEFAULT_SETTINGS.nostrReadRelayExclusions;
+  @tracked nostrWriteRelayExclusions =
+    DEFAULT_SETTINGS.nostrWriteRelayExclusions;
   @tracked experimentalEnablePhotoDeletion =
     DEFAULT_SETTINGS.experimentalEnablePhotoDeletion;
 
@@ -111,6 +116,8 @@ export default class SettingsService extends Service {
     this.nostrPhotoFallbackUploads = finalSettings.nostrPhotoFallbackUploads;
     this.nostrReadRelays = finalSettings.nostrReadRelays;
     this.nostrWriteRelays = finalSettings.nostrWriteRelays;
+    this.nostrReadRelayExclusions = finalSettings.nostrReadRelayExclusions;
+    this.nostrWriteRelayExclusions = finalSettings.nostrWriteRelayExclusions;
     this.experimentalEnablePhotoDeletion =
       finalSettings.experimentalEnablePhotoDeletion;
 
@@ -127,6 +134,8 @@ export default class SettingsService extends Service {
       nostrPhotoFallbackUploads: this.nostrPhotoFallbackUploads,
       nostrReadRelays: this.nostrReadRelays,
       nostrWriteRelays: this.nostrWriteRelays,
+      nostrReadRelayExclusions: this.nostrReadRelayExclusions,
+      nostrWriteRelayExclusions: this.nostrWriteRelayExclusions,
       experimentalEnablePhotoDeletion: this.experimentalEnablePhotoDeletion,
     };
     localStorage.setItem('marco:settings', JSON.stringify(settings));
diff --git a/app/utils/nostr.js b/app/utils/nostr.js
index bf09957..989cf79 100644
--- a/app/utils/nostr.js
+++ b/app/utils/nostr.js
@@ -14,6 +14,30 @@ export function normalizeRelayUrl(url) {
   return normalized;
 }
 
+export function uniqNormalizedRelays(relays = []) {
+  return Array.from(new Set(relays.map(normalizeRelayUrl).filter(Boolean)));
+}
+
+export function mergeRequiredRelays(requiredRelays = [], customRelays = []) {
+  const requiredSet = new Set(requiredRelays.filter(Boolean));
+  const merged = [...requiredRelays.filter(Boolean)];
+
+  for (const relay of uniqNormalizedRelays(customRelays)) {
+    if (!requiredSet.has(relay)) {
+      merged.push(relay);
+    }
+  }
+
+  return merged;
+}
+
+export function excludeRequiredRelays(customRelays = [], requiredRelays = []) {
+  const requiredSet = new Set(requiredRelays.filter(Boolean));
+  return uniqNormalizedRelays(customRelays).filter((relay) => {
+    return !requiredSet.has(relay);
+  });
+}
+
 /**
  * Extracts and normalizes photo data from NIP-360 (Place Photos) events.
  * Sorts chronologically and guarantees the first landscape photo (or first portrait) is at index 0.
diff --git a/tests/helpers/mock-nostr.js b/tests/helpers/mock-nostr.js
index 00d9a5a..40ed0f0 100644
--- a/tests/helpers/mock-nostr.js
+++ b/tests/helpers/mock-nostr.js
@@ -49,11 +49,19 @@ export class MockNostrDataService extends Service {
     return [];
   }
 
-  get defaultReadRelays() {
+  get requiredReadRelays() {
     return [];
   }
 
-  get defaultWriteRelays() {
+  get requiredWriteRelays() {
+    return [];
+  }
+
+  get mailboxReadRelays() {
+    return [];
+  }
+
+  get mailboxWriteRelays() {
     return [];
   }
 
diff --git a/tests/integration/components/app-menu/settings/nostr-test.gjs b/tests/integration/components/app-menu/settings/nostr-test.gjs
new file mode 100644
index 0000000..5fcac34
--- /dev/null
+++ b/tests/integration/components/app-menu/settings/nostr-test.gjs
@@ -0,0 +1,188 @@
+import { module, test } from 'qunit';
+import { setupRenderingTest } from 'marco/tests/helpers';
+import { click, fillIn, render } from '@ember/test-helpers';
+import Service, { service } from '@ember/service';
+import AppMenuSettingsNostr from 'marco/components/app-menu/settings/nostr';
+import {
+  excludeRequiredRelays,
+  mergeRequiredRelays,
+  uniqNormalizedRelays,
+} from 'marco/utils/nostr';
+
+class MockNostrDataService extends Service {
+  @service settings;
+
+  requiredReadRelays = ['wss://nostr.kosmos.org'];
+  requiredWriteRelays = [];
+
+  mailboxReadRelays = ['wss://mailbox.example.com'];
+  mailboxWriteRelays = ['wss://mailbox-write.example.com'];
+
+  get configuredReadRelays() {
+    const configured = uniqNormalizedRelays([
+      ...this.mailboxReadRelays,
+      ...(this.settings.nostrReadRelays || []),
+    ]);
+
+    return excludeRequiredRelays(
+      configured,
+      this.settings.nostrReadRelayExclusions || []
+    );
+  }
+
+  get configuredWriteRelays() {
+    const configured = uniqNormalizedRelays([
+      ...this.mailboxWriteRelays,
+      ...(this.settings.nostrWriteRelays || []),
+    ]);
+
+    return excludeRequiredRelays(
+      configured,
+      this.settings.nostrWriteRelayExclusions || []
+    );
+  }
+
+  get activeReadRelays() {
+    return mergeRequiredRelays(
+      this.requiredReadRelays,
+      this.configuredReadRelays
+    );
+  }
+
+  get activeWriteRelays() {
+    return mergeRequiredRelays(
+      this.requiredWriteRelays,
+      this.configuredWriteRelays
+    );
+  }
+
+  async clearCache() {}
+}
+
+function readRows(element) {
+  const list = element.querySelectorAll('.relay-list')[0];
+  return [...list.querySelectorAll('li')];
+}
+
+function writeRows(element) {
+  const list = element.querySelectorAll('.relay-list')[1];
+  return [...list.querySelectorAll('li')];
+}
+
+function rowByText(rows, text) {
+  return rows.find((row) => row.textContent.includes(text));
+}
+
+module('Integration | Component | app-menu/settings/nostr', function (hooks) {
+  setupRenderingTest(hooks);
+
+  hooks.beforeEach(function () {
+    localStorage.removeItem('marco:settings');
+
+    this.owner.register('service:nostrData', MockNostrDataService);
+    this.settings = this.owner.lookup('service:settings');
+    this.onChange = () => {};
+  });
+
+  hooks.afterEach(function () {
+    localStorage.removeItem('marco:settings');
+  });
+
+  async function renderAndOpenDetails(context) {
+    await render(
+      <template><AppMenuSettingsNostr @onChange={{this.onChange}} /></template>
+    );
+    await click('summary');
+    return context.element;
+  }
+
+  test('required read relay is first and non-removable', async function (assert) {
+    const element = await renderAndOpenDetails(this);
+    const rows = readRows(element);
+
+    assert.dom(rows[0]).includesText('nostr.kosmos.org');
+
+    const requiredRow = rowByText(rows, 'nostr.kosmos.org');
+    const mailboxRow = rowByText(rows, 'mailbox.example.com');
+
+    assert.dom(requiredRow.querySelector('.btn-remove-relay')).doesNotExist();
+    assert.dom(mailboxRow.querySelector('.btn-remove-relay')).exists();
+  });
+
+  test('removing mailbox read relay stores exclusion override', async function (assert) {
+    const element = await renderAndOpenDetails(this);
+    const mailboxRow = rowByText(readRows(element), 'mailbox.example.com');
+
+    await click(mailboxRow.querySelector('.btn-remove-relay'));
+
+    assert.deepEqual(this.settings.nostrReadRelayExclusions, [
+      'wss://mailbox.example.com',
+    ]);
+    assert.strictEqual(this.settings.nostrReadRelays, null);
+  });
+
+  test('removing custom read relay updates custom list without exclusions', async function (assert) {
+    this.settings.update('nostrReadRelays', ['wss://custom.example.com']);
+
+    const element = await renderAndOpenDetails(this);
+    const customRow = rowByText(readRows(element), 'custom.example.com');
+
+    await click(customRow.querySelector('.btn-remove-relay'));
+
+    assert.strictEqual(this.settings.nostrReadRelays, null);
+    assert.strictEqual(this.settings.nostrReadRelayExclusions, null);
+  });
+
+  test('adding read relay clears existing exclusion for same relay', async function (assert) {
+    this.settings.update('nostrReadRelayExclusions', [
+      'wss://mailbox.example.com',
+    ]);
+
+    const element = await renderAndOpenDetails(this);
+
+    await fillIn('#new-read-relay', 'Mailbox.EXAMPLE.com/');
+    await click(element.querySelector('#new-read-relay').nextElementSibling);
+
+    assert.deepEqual(this.settings.nostrReadRelays, [
+      'wss://mailbox.example.com',
+    ]);
+    assert.strictEqual(this.settings.nostrReadRelayExclusions, null);
+  });
+
+  test('reset read relays clears additions and exclusions', async function (assert) {
+    this.settings.update('nostrReadRelays', ['wss://custom.example.com']);
+    this.settings.update('nostrReadRelayExclusions', [
+      'wss://mailbox.example.com',
+    ]);
+
+    const element = await renderAndOpenDetails(this);
+    await click(element.querySelectorAll('.reset-relays')[0]);
+
+    assert.strictEqual(this.settings.nostrReadRelays, null);
+    assert.strictEqual(this.settings.nostrReadRelayExclusions, null);
+
+    const requiredRow = rowByText(readRows(element), 'nostr.kosmos.org');
+    assert.dom(requiredRow).exists();
+  });
+
+  test('write relays are removable and mailbox delete stores exclusion', async function (assert) {
+    this.settings.update('nostrWriteRelays', [
+      'wss://custom-write.example.com',
+    ]);
+
+    const element = await renderAndOpenDetails(this);
+    const rows = writeRows(element);
+
+    assert.true(
+      rows.every((row) => row.querySelector('.btn-remove-relay')),
+      'all write relays can be removed'
+    );
+
+    const mailboxRow = rowByText(rows, 'mailbox-write.example.com');
+    await click(mailboxRow.querySelector('.btn-remove-relay'));
+
+    assert.deepEqual(this.settings.nostrWriteRelayExclusions, [
+      'wss://mailbox-write.example.com',
+    ]);
+  });
+});
diff --git a/tests/unit/utils/nostr-test.js b/tests/unit/utils/nostr-test.js
index 19e51b7..e14349a 100644
--- a/tests/unit/utils/nostr-test.js
+++ b/tests/unit/utils/nostr-test.js
@@ -1,5 +1,11 @@
 import { module, test } from 'qunit';
-import { normalizeRelayUrl, parsePlacePhotos } from 'marco/utils/nostr';
+import {
+  excludeRequiredRelays,
+  mergeRequiredRelays,
+  normalizeRelayUrl,
+  parsePlacePhotos,
+  uniqNormalizedRelays,
+} from 'marco/utils/nostr';
 
 module('Unit | Utility | nostr', function () {
   test('normalizeRelayUrl normalizes protocol, case, and slashes', function (assert) {
@@ -141,4 +147,59 @@ module('Unit | Utility | nostr', function () {
     assert.strictEqual(photos[0].placeIdentifier, 'osm:node:123');
     assert.strictEqual(photos[1].placeIdentifier, 'osm:node:456');
   });
+
+  test('uniqNormalizedRelays returns normalized unique relays', function (assert) {
+    const relays = uniqNormalizedRelays([
+      'Relay.example.com',
+      'wss://relay.example.com/',
+      'wss://other.example.com',
+    ]);
+
+    assert.deepEqual(relays, [
+      'wss://relay.example.com',
+      'wss://other.example.com',
+    ]);
+  });
+
+  test('mergeRequiredRelays keeps required relays as-is and merges normalized custom relays', function (assert) {
+    const relays = mergeRequiredRelays(
+      ['wss://required.example.com', 'required-2.example.com'],
+      ['required-2.example.com/', 'wss://custom.example.com']
+    );
+
+    assert.deepEqual(relays, [
+      'wss://required.example.com',
+      'required-2.example.com',
+      'wss://required-2.example.com',
+      'wss://custom.example.com',
+    ]);
+  });
+
+  test('excludeRequiredRelays removes required relays from normalized custom list', function (assert) {
+    const relays = excludeRequiredRelays(
+      [
+        'wss://required.example.com',
+        'custom.example.com',
+        'ws://custom2.example.com',
+      ],
+      ['wss://required.example.com']
+    );
+
+    assert.deepEqual(relays, [
+      'wss://custom.example.com',
+      'ws://custom2.example.com',
+    ]);
+  });
+
+  test('excludeRequiredRelays trusts required list without normalizing it', function (assert) {
+    const relays = excludeRequiredRelays(
+      ['Required.example.com', 'custom.example.com'],
+      ['required.example.com']
+    );
+
+    assert.deepEqual(relays, [
+      'wss://required.example.com',
+      'wss://custom.example.com',
+    ]);
+  });
 });