diff --git a/web/app/components/document/sidebar/header.ts b/web/app/components/document/sidebar/header.ts
index f80d2c075..9cf17e5d3 100644
--- a/web/app/components/document/sidebar/header.ts
+++ b/web/app/components/document/sidebar/header.ts
@@ -2,6 +2,7 @@ import Component from "@glimmer/component";
 import ConfigService from "hermes/services/config";
 import { inject as service } from "@ember/service";
 import { HermesDocument } from "hermes/types/document";
+import isValidURL from "hermes/utils/is-valid-u-r-l";
 
 interface DocumentSidebarHeaderComponentSignature {
   Args: {
@@ -12,15 +13,6 @@ interface DocumentSidebarHeaderComponentSignature {
   };
 }
 
-export function isValidURL(input: string) {
-  try {
-    new URL(input);
-    return true;
-  } catch {
-    return false;
-  }
-}
-
 export default class DocumentSidebarHeaderComponent extends Component<DocumentSidebarHeaderComponentSignature> {
   @service("config") declare configSvc: ConfigService;
 
diff --git a/web/app/components/document/sidebar/related-resources/add.ts b/web/app/components/document/sidebar/related-resources/add.ts
index d4b48523c..f89da313d 100644
--- a/web/app/components/document/sidebar/related-resources/add.ts
+++ b/web/app/components/document/sidebar/related-resources/add.ts
@@ -13,6 +13,7 @@ import {
   RelatedHermesDocument,
 } from "hermes/components/document/sidebar/related-resources";
 import Ember from "ember";
+import isValidURL from "hermes/utils/is-valid-u-r-l";
 
 interface DocumentSidebarRelatedResourcesAddComponentSignature {
   Element: null;
@@ -48,7 +49,6 @@ export default class DocumentSidebarRelatedResourcesAddComponent extends Compone
 
   @tracked externalLinkTitle = "";
 
-
   get noMatchesFound(): boolean {
     const objectEntriesLengthIsZero =
       Object.entries(this.args.shownDocuments).length === 0;
@@ -127,6 +127,7 @@ export default class DocumentSidebarRelatedResourcesAddComponent extends Compone
       return link.url === externalLink.url;
     });
 
+
     if (isDuplicate) {
       this.showDuplicateMessage();
     } else {
@@ -218,15 +219,9 @@ export default class DocumentSidebarRelatedResourcesAddComponent extends Compone
   });
 
   protected checkURL = restartableTask(async () => {
-    const url = this.query;
-    try {
-      this.queryIsURL = Boolean(new URL(url));
-    } catch (e) {
-      this.queryIsURL = false;
-    } finally {
-      if (this.queryIsURL) {
-        void this.fetchURLInfo.perform();
-      }
+    this.queryIsURL = await isValidURL(this.query);
+    if (this.queryIsURL) {
+      void this.fetchURLInfo.perform();
     }
   });
 }
diff --git a/web/app/components/document/sidebar/related-resources/add/external-resource.hbs b/web/app/components/document/sidebar/related-resources/add/external-resource.hbs
index 76e2d14b7..119bd6d7c 100644
--- a/web/app/components/document/sidebar/related-resources/add/external-resource.hbs
+++ b/web/app/components/document/sidebar/related-resources/add/external-resource.hbs
@@ -12,21 +12,22 @@
       </div>
     {{else}}
       <div class="w-full" data-test-add-external-resource-form>
-        <form {{on "submit" @onSubmit}} class="mb-2.5">
+        <form {{on "submit" @onSubmit}} class="mb-3">
           <Hds::Form::TextInput::Field
             {{on "input" @onInput}}
             @value={{@title}}
-            placeholder="Enter a title"
+            placeholder="Optional"
             required={{true}}
             class="external-resource-title-input"
             as |F|
-          />
+          >
+            <F.Label>Title</F.Label>
+          </Hds::Form::TextInput::Field>
         </form>
         <div class="external-resource-url">
-          <div
-            class="truncate"
-            data-test-add-external-resource-truncated-url
-          >{{@url}}</div>
+          <div class="truncate" data-test-add-external-resource-truncated-url>
+            {{@url}}
+          </div>
           <div class="external-resource-favicon">
             <FlightIcon @name={{get-link-icon @url}} />
           </div>
diff --git a/web/app/components/document/sidebar/related-resources/list-item.hbs b/web/app/components/document/sidebar/related-resources/list-item.hbs
index 93619e376..41b773ee7 100644
--- a/web/app/components/document/sidebar/related-resources/list-item.hbs
+++ b/web/app/components/document/sidebar/related-resources/list-item.hbs
@@ -16,7 +16,6 @@
         />
       </LinkTo>
     {{else}}
-      {{log @resource}}
       <ExternalLink
         data-test-item-type="external-resource"
         href={{this.externalResourceURL}}
@@ -41,6 +40,5 @@
     @resource={{this.externalLink}}
     @hideModal={{this.hideModal}}
     @onSave={{this.saveChanges}}
-    @url={{this.externalResourceURL}}
   />
 {{/if}}
diff --git a/web/app/components/document/sidebar/related-resources/list-item/edit.hbs b/web/app/components/document/sidebar/related-resources/list-item/edit.hbs
index 0a13de5d8..7c74107ee 100644
--- a/web/app/components/document/sidebar/related-resources/list-item/edit.hbs
+++ b/web/app/components/document/sidebar/related-resources/list-item/edit.hbs
@@ -6,10 +6,15 @@
   >
     <M.Header>Edit resource</M.Header>
     <M.Body>
-      <form {{did-insert this.registerForm}} class="px-6 pb-6" {{on "submit" this.onSave}}>
+      <form
+        {{did-insert this.registerForm}}
+        class="px-6 pb-6"
+        {{on "submit" (perform this.onSave)}}
+      >
         <Hds::Form::TextInput::Field
           {{on "input" this.updateFormValues}}
           @value={{this.title}}
+          placeholder="Optional"
           required={{true}}
           name="title"
           class="external-resource-title-input mb-4"
@@ -25,6 +30,11 @@
           as |F|
         >
           <F.Label>URL</F.Label>
+          {{#if this.errorMessageIsShown}}
+            <F.Error class="mt-3">
+              A valid URL is required.
+            </F.Error>
+          {{/if}}
         </Hds::Form::TextInput::Field>
         {{! This adds enter-to-submit functionality }}
         <input type="submit" class="hidden" />
@@ -37,13 +47,19 @@
           @text="Save changes"
           @color="primary"
           {{! Should it show a flashMessage? }}
-          {{on "click" this.onSave}}
+          {{on "click" (perform this.onSave)}}
         />
         <Hds::Button
           @text="Cancel"
           @color="secondary"
           {{on "click" @hideModal}}
         />
+        <Hds::Button
+          @text="Delete"
+          @color="tertiary"
+          @icon="trash"
+          class="text-color-foreground-critical hover:text-color-foreground-critical-on-surface"
+        />
       </Hds::ButtonSet>
     </M.Footer>
   </Hds::Modal>
diff --git a/web/app/components/document/sidebar/related-resources/list-item/edit.ts b/web/app/components/document/sidebar/related-resources/list-item/edit.ts
index e0f181ea9..cda37fdf3 100644
--- a/web/app/components/document/sidebar/related-resources/list-item/edit.ts
+++ b/web/app/components/document/sidebar/related-resources/list-item/edit.ts
@@ -2,15 +2,15 @@ import { assert } from "@ember/debug";
 import { action } from "@ember/object";
 import Component from "@glimmer/component";
 import { tracked } from "@glimmer/tracking";
+import { restartableTask } from "ember-concurrency";
 import { RelatedExternalLink } from "hermes/components/document/sidebar/related-resources";
+import isValidURL from "hermes/utils/is-valid-u-r-l";
 
 interface DocumentSidebarRelatedResourcesListItemEditComponentSignature {
   Args: {
     resource: RelatedExternalLink;
     hideModal: () => void;
     onSave: (resource: RelatedExternalLink) => void;
-    // Temporary workaround until this is an attribute of the resource
-    url: string;
   };
   Blocks: {
     default: [];
@@ -20,11 +20,15 @@ interface DocumentSidebarRelatedResourcesListItemEditComponentSignature {
 export default class DocumentSidebarRelatedResourcesListItemEditComponent extends Component<DocumentSidebarRelatedResourcesListItemEditComponentSignature> {
   @tracked resource = this.args.resource;
 
-  @tracked url = this.args.url;
+  @tracked url = this.args.resource.url;
   @tracked title = this.args.resource.title;
 
+  @tracked errorMessageIsShown = false;
+
   @tracked _form: HTMLFormElement | null = null;
 
+  @tracked urlIsValid = false;
+
   @action protected registerForm(form: HTMLFormElement): void {
     this._form = form;
   }
@@ -45,20 +49,34 @@ export default class DocumentSidebarRelatedResourcesListItemEditComponent extend
 
     this.title = title;
     this.url = url;
+
+    void this.validateURL.perform();
   }
 
-  @action protected onSave(): void {
+  protected validateURL = restartableTask(async () => {
+    this.urlIsValid = await isValidURL(this.url);
+    this.errorMessageIsShown = !this.urlIsValid;
+  });
+
+  protected onSave = restartableTask(async (e: Event) => {
+    // prevent the form from submitting on enter
+    e.preventDefault();
+
     let newResource = this.args.resource;
     newResource.url = this.url;
     newResource.title = this.title;
 
-    // TODO: validate fields
-    // if the title is empty, use a fallback (url, domain)
-    // validate that the url is a valid url
-    // if the url is invalid, show an error message and start eager validation
+    await this.validateURL.perform();
 
-    this.args.onSave(newResource);
-  }
+    if (this.urlIsValid) {
+      if (!this.args.resource.title.length) {
+        newResource.title = this.url;
+      }
+      this.args.onSave(newResource);
+    } else {
+      this.errorMessageIsShown = true;
+    }
+  });
 }
 
 declare module "@glint/environment-ember-loose/registry" {
diff --git a/web/app/components/document/sidebar/related-resources/list-item/resource.hbs b/web/app/components/document/sidebar/related-resources/list-item/resource.hbs
index c754737e9..8688e10b7 100644
--- a/web/app/components/document/sidebar/related-resources/list-item/resource.hbs
+++ b/web/app/components/document/sidebar/related-resources/list-item/resource.hbs
@@ -8,7 +8,7 @@
   {{else}}
     <FlightIcon
       @name={{get-link-icon this.url}}
-      class={{if (eq (get-link-icon this.url) "external-link") "opacity-50"}}
+      class={{if (eq (get-link-icon this.url) "file") "opacity-40"}}
     />
   {{/if}}
 </div>
@@ -18,7 +18,7 @@
     @tagName="h4"
     class="text-body-200 text-color-foreground-strong font-medium"
   >
-    {{@resource.title}}
+    {{this.title}}
   </TruncatedText>
   {{#if this.resourceIsDocument}}
     <div class="text-color-foreground-faint text-body-100 mt-px">
diff --git a/web/app/components/document/sidebar/related-resources/list-item/resource.ts b/web/app/components/document/sidebar/related-resources/list-item/resource.ts
index eed234bf6..72ff9ada9 100644
--- a/web/app/components/document/sidebar/related-resources/list-item/resource.ts
+++ b/web/app/components/document/sidebar/related-resources/list-item/resource.ts
@@ -1,6 +1,9 @@
 import { action } from "@ember/object";
 import Component from "@glimmer/component";
-import { RelatedHermesDocument, RelatedResource } from "../../related-resources";
+import {
+  RelatedHermesDocument,
+  RelatedResource,
+} from "../../related-resources";
 import { assert } from "@ember/debug";
 
 interface DocumentSidebarRelatedResourcesListItemResourceComponentSignature {
@@ -25,6 +28,13 @@ export default class DocumentSidebarRelatedResourcesListItemResourceComponent ex
     return this.args.resource.documentNumber;
   }
 
+  protected get title() {
+    if ("url" in this.args.resource) {
+      return this.args.resource.title || this.url;
+    }
+    return this.args.resource.title;
+  }
+
   assertResourceIsDocument(
     document: RelatedResource
   ): asserts document is RelatedHermesDocument {
diff --git a/web/app/helpers/get-link-icon.ts b/web/app/helpers/get-link-icon.ts
index a3597427c..304b6e9d1 100644
--- a/web/app/helpers/get-link-icon.ts
+++ b/web/app/helpers/get-link-icon.ts
@@ -42,7 +42,7 @@ const getLinkIconHelper = helper<GetLinkIconSignature>(([url]) => {
       }
     }
   }
-  return "external-link";
+  return "file";
 });
 
 export default getLinkIconHelper;
diff --git a/web/app/styles/components/document/related-resources.scss b/web/app/styles/components/document/related-resources.scss
index ab8e4cffb..d6ba655db 100644
--- a/web/app/styles/components/document/related-resources.scss
+++ b/web/app/styles/components/document/related-resources.scss
@@ -115,6 +115,10 @@
 
 .external-resource-title-input {
   @apply text-display-300 font-semibold h-11 px-2.5;
+
+  &::placeholder {
+    @apply opacity-50;
+  }
 }
 
 .external-resource-url {
diff --git a/web/app/utils/is-valid-u-r-l.ts b/web/app/utils/is-valid-u-r-l.ts
new file mode 100644
index 000000000..e53a1a440
--- /dev/null
+++ b/web/app/utils/is-valid-u-r-l.ts
@@ -0,0 +1,8 @@
+export default async function isValidURL(string: string): Promise<boolean> {
+  try {
+    new URL(string);
+    return true;
+  } catch {
+    return false;
+  }
+}