diff --git a/httpd-client/index.ts b/httpd-client/index.ts
index 2590179e2..82dadc087 100644
--- a/httpd-client/index.ts
+++ b/httpd-client/index.ts
@@ -1,7 +1,6 @@
 import type { BaseUrl } from "./lib/fetcher.js";
 import type {
   Blob,
-  CommitBlob,
   Project,
   Remote,
   Tree,
@@ -10,8 +9,10 @@ import type {
 import type { Comment } from "./lib/project/comment.js";
 import type {
   Commit,
+  CommitBlob,
   CommitHeader,
   Diff,
+  DiffBlob,
   DiffContent,
   DiffFile,
   HunkLine,
@@ -46,6 +47,7 @@ export type {
   CommitBlob,
   CommitHeader,
   Diff,
+  DiffBlob,
   DiffContent,
   DiffFile,
   DiffResponse,
diff --git a/httpd-client/lib/project.ts b/httpd-client/lib/project.ts
index 6ef6c88c6..5b9d04f1a 100644
--- a/httpd-client/lib/project.ts
+++ b/httpd-client/lib/project.ts
@@ -29,6 +29,7 @@ import {
 } from "zod";
 
 import {
+  diffBlobSchema,
   commitHeaderSchema,
   commitSchema,
   commitsSchema,
@@ -86,14 +87,6 @@ const blobSchema = object({
 
 export type Blob = z.infer<typeof blobSchema>;
 
-const commitBlobSchema = object({
-  binary: boolean(),
-  content: optional(string()),
-  lastCommit: commitHeaderSchema,
-});
-
-export type CommitBlob = z.infer<typeof commitBlobSchema>;
-
 const treeEntrySchema = object({
   path: string(),
   name: string(),
@@ -138,7 +131,7 @@ export type DiffResponse = z.infer<typeof diffResponseSchema>;
 const diffResponseSchema = object({
   commits: array(commitHeaderSchema),
   diff: diffSchema,
-  files: record(string(), commitBlobSchema),
+  files: record(string(), diffBlobSchema),
 });
 
 export class Client {
diff --git a/httpd-client/lib/project/commit.ts b/httpd-client/lib/project/commit.ts
index ed0043c09..9a8f60464 100644
--- a/httpd-client/lib/project/commit.ts
+++ b/httpd-client/lib/project/commit.ts
@@ -1,17 +1,34 @@
 import type { z } from "zod";
 export type {
+  Commit,
+  CommitHeader,
   Commits,
+  Diff,
+  DiffContent,
+  DiffFile,
   HunkLine,
   Hunks,
-  Commit,
-  Diff,
-  CommitHeader,
-  DiffFile,
-  DiffContent,
 };
 
-import { array, literal, number, object, optional, string, union } from "zod";
-export { commitHeaderSchema, diffSchema, commitSchema, commitsSchema };
+import {
+  array,
+  boolean,
+  literal,
+  number,
+  object,
+  optional,
+  record,
+  string,
+  union,
+} from "zod";
+export {
+  commitBlobSchema,
+  commitHeaderSchema,
+  commitSchema,
+  commitsSchema,
+  diffBlobSchema,
+  diffSchema,
+};
 
 const gitPersonSchema = object({
   name: string(),
@@ -29,6 +46,22 @@ const commitHeaderSchema = object({
   committer: gitPersonSchema.merge(object({ time: number() })),
 });
 
+const diffBlobSchema = object({
+  binary: boolean(),
+  content: string(),
+  id: string(),
+  lastCommit: commitHeaderSchema,
+});
+
+export type DiffBlob = z.infer<typeof diffBlobSchema>;
+
+const commitBlobSchema = object({
+  binary: boolean(),
+  content: string(),
+});
+
+export type CommitBlob = z.infer<typeof commitBlobSchema>;
+
 type AdditionHunkLine = z.infer<typeof additionHunkLineSchema>;
 
 const additionHunkLineSchema = object({
@@ -146,12 +179,13 @@ const commitSchema = object({
   commit: commitHeaderSchema,
   diff: diffSchema,
   branches: array(string()),
+  files: record(string(), commitBlobSchema),
 });
 
 type Commits = z.infer<typeof commitsSchema>;
 
 const commitsSchema = object({
-  commits: array(commitSchema),
+  commits: array(commitSchema.omit({ files: true })),
   stats: object({
     commits: number(),
     branches: number(),
diff --git a/src/components/Observer.svelte b/src/components/Observer.svelte
new file mode 100644
index 000000000..081411080
--- /dev/null
+++ b/src/components/Observer.svelte
@@ -0,0 +1,41 @@
+<script lang="ts" context="module">
+  export function intersection(
+    node: HTMLElement,
+    observer: IntersectionObserver | undefined,
+  ) {
+    if (!observer) return;
+    observer.observe(node);
+    return {
+      destroy() {
+        observer.unobserve(node);
+      },
+    };
+  }
+</script>
+
+<script lang="ts">
+  import { onDestroy } from "svelte";
+
+  let observer: IntersectionObserver | undefined = undefined;
+  let filesVisibility = new Set<string>();
+
+  if ("IntersectionObserver" in window) {
+    observer = new IntersectionObserver(entries => {
+      entries.forEach(entry => {
+        if (entry.isIntersecting) {
+          filesVisibility = filesVisibility.add(
+            entry.target.id.replace("observer:", ""),
+          );
+        }
+      });
+    });
+  }
+
+  onDestroy(() => {
+    if (observer) {
+      observer.disconnect();
+    }
+  });
+</script>
+
+<slot {observer} {filesVisibility} />
diff --git a/src/views/projects/Changeset.svelte b/src/views/projects/Changeset.svelte
index 3e29ae8c0..146181d3b 100644
--- a/src/views/projects/Changeset.svelte
+++ b/src/views/projects/Changeset.svelte
@@ -1,8 +1,8 @@
 <script lang="ts">
   import type {
     BaseUrl,
-    Diff,
     CommitBlob,
+    Diff,
     DiffContent,
     DiffFile,
   } from "@httpd-client";
@@ -11,14 +11,13 @@
 
   import FileDiff from "@app/views/projects/Changeset/FileDiff.svelte";
   import FileLocationChange from "@app/views/projects/Changeset/FileLocationChange.svelte";
+  import Observer, { intersection } from "@app/components/Observer.svelte";
 
   export let diff: Diff;
-  // This only is needed in commit view where we have a useful revision.
-  export let revision: string | undefined = undefined;
-  // This only is needed for patch changesets where we have different files with different last commits.
-  export let files: Record<string, CommitBlob> = {};
+  export let files: Record<string, CommitBlob>;
   export let baseUrl: BaseUrl;
   export let projectId: string;
+  export let revision: string;
 
   const diffDescription = ({
     modified,
@@ -86,57 +85,77 @@
   </span>
 </div>
 <div class="diff-listing">
-  {#each diff.added as file}
-    <FileDiff
-      {projectId}
-      {baseUrl}
-      revision={revision ?? files[file.new.oid].lastCommit.id}
-      filePath={file.path}
-      fileDiff={{ ...file.diff, type: getFileType(file.diff, file.new) }}
-      headerBadgeCaption="added" />
-  {/each}
-  {#each diff.deleted as file}
-    <FileDiff
-      {projectId}
-      {baseUrl}
-      revision={revision ?? files[file.old.oid].lastCommit.id}
-      filePath={file.path}
-      fileDiff={{ ...file.diff, type: getFileType(file.diff, file.old) }}
-      headerBadgeCaption="deleted" />
-  {/each}
-  {#each diff.modified as file}
-    <FileDiff
-      {projectId}
-      {baseUrl}
-      revision={revision ?? files[file.new.oid].lastCommit.id}
-      filePath={file.path}
-      fileDiff={{ ...file.diff, type: getFileType(file.diff, file.new) }} />
-  {/each}
-  {#each diff.moved as file}
-    {#if file.diff}
-      <FileDiff
-        {projectId}
-        {baseUrl}
-        {revision}
-        filePath={file.newPath}
-        oldFilePath={file.oldPath}
-        fileDiff={file.diff}
-        headerBadgeCaption="moved" />
-    {:else}
+  <Observer let:filesVisibility let:observer>
+    {#each diff.added as file}
+      <div use:intersection={observer} id={"observer:" + file.path}>
+        <FileDiff
+          {projectId}
+          {baseUrl}
+          {revision}
+          visible={filesVisibility.has(file.path)}
+          content={files[file.new.oid]?.content}
+          filePath={file.path}
+          fileDiff={{ ...file.diff, type: getFileType(file.diff, file.new) }}
+          headerBadgeCaption="added" />
+      </div>
+    {/each}
+    {#each diff.deleted as file}
+      <div use:intersection={observer} id={"observer:" + file.path}>
+        <FileDiff
+          {projectId}
+          {baseUrl}
+          {revision}
+          visible={filesVisibility.has(file.path)}
+          oldContent={files[file.old.oid]?.content}
+          filePath={file.path}
+          fileDiff={{ ...file.diff, type: getFileType(file.diff, file.old) }}
+          headerBadgeCaption="deleted" />
+      </div>
+    {/each}
+    {#each diff.modified as file}
+      <div use:intersection={observer} id={"observer:" + file.path}>
+        <FileDiff
+          {projectId}
+          {baseUrl}
+          {revision}
+          visible={filesVisibility.has(file.path)}
+          oldContent={files[file.old.oid]?.content}
+          content={files[file.new.oid]?.content}
+          filePath={file.path}
+          fileDiff={{ ...file.diff, type: getFileType(file.diff, file.new) }} />
+      </div>
+    {/each}
+    {#each diff.moved as file}
+      {#if file.diff}
+        <div use:intersection={observer} id={"observer:" + file.newPath}>
+          <FileDiff
+            {projectId}
+            {baseUrl}
+            {revision}
+            content=""
+            visible={filesVisibility.has(file.newPath)}
+            filePath={file.newPath}
+            oldFilePath={file.oldPath}
+            fileDiff={file.diff}
+            headerBadgeCaption="moved" />
+        </div>
+      {:else}
+        <FileLocationChange
+          {projectId}
+          {baseUrl}
+          {revision}
+          newPath={file.newPath}
+          oldPath={file.oldPath}
+          mode="moved" />
+      {/if}
+    {/each}
+    {#each diff.copied as file}
       <FileLocationChange
         {projectId}
         {baseUrl}
         newPath={file.newPath}
         oldPath={file.oldPath}
-        mode="moved" />
-    {/if}
-  {/each}
-  {#each diff.copied as file}
-    <FileLocationChange
-      {projectId}
-      {baseUrl}
-      newPath={file.newPath}
-      oldPath={file.oldPath}
-      mode="copied" />
-  {/each}
+        mode="copied" />
+    {/each}
+  </Observer>
 </div>
diff --git a/src/views/projects/Changeset/FileDiff.svelte b/src/views/projects/Changeset/FileDiff.svelte
index c736abda6..901744980 100644
--- a/src/views/projects/Changeset/FileDiff.svelte
+++ b/src/views/projects/Changeset/FileDiff.svelte
@@ -1,12 +1,17 @@
 <script lang="ts">
-  import { onDestroy, onMount } from "svelte";
   import type { BaseUrl, DiffContent, HunkLine } from "@httpd-client";
 
+  import { onDestroy, onMount } from "svelte";
+  import { toHtml } from "hast-util-to-html";
+
+  import * as Syntax from "@app/lib/syntax";
   import Badge from "@app/components/Badge.svelte";
   import Icon from "@app/components/Icon.svelte";
   import Link from "@app/components/Link.svelte";
 
   export let filePath: string;
+  export let oldContent: string | undefined = undefined;
+  export let content: string | undefined = undefined;
   export let oldFilePath: string | undefined = undefined;
   export let fileDiff: DiffContent;
   export let revision: string | undefined = undefined;
@@ -18,9 +23,11 @@
     | undefined = undefined;
   export let baseUrl: BaseUrl;
   export let projectId: string;
+  export let visible: boolean = false;
 
   let collapsed = false;
   let selection: Selection | undefined = undefined;
+  let highlighting: { new?: string[]; old?: string[] } | undefined = undefined;
 
   onMount(() => {
     window.addEventListener("click", deselectHandler);
@@ -39,6 +46,10 @@
     }
   });
 
+  $: if (visible) {
+    void highlightContent().then(output => (highlighting = output));
+  }
+
   onDestroy(() => {
     window.removeEventListener("click", deselectHandler);
     window.removeEventListener("hashchange", updateSelection);
@@ -55,6 +66,24 @@
     }
   }
 
+  async function highlightContent() {
+    const extension = filePath.split(".").pop();
+    const highlighted: { new?: string[]; old?: string[] } = {};
+    if (extension) {
+      if (content) {
+        highlighted["new"] = toHtml(
+          await Syntax.highlight(content, extension),
+        ).split("\n");
+      }
+      if (oldContent) {
+        highlighted["old"] = toHtml(
+          await Syntax.highlight(oldContent, extension),
+        ).split("\n");
+      }
+    }
+    return Object.entries(highlighted).length > 0 ? highlighted : undefined;
+  }
+
   function updateSelection() {
     const fragment = window.location.hash.substring(1);
     const match = fragment.match(/(.+):H(\d+)L(\d+)(H(\d+)L(\d+))?/);
@@ -298,6 +327,7 @@
     padding: 0 0.75rem 0 0.5rem;
   }
   .diff-line-content {
+    color: unset !important;
     white-space: pre-wrap;
     overflow-wrap: anywhere;
     width: 100%;
@@ -395,7 +425,19 @@
                   <td class="diff-line-type" data-line-type={line.type}>
                     {lineSign(line)}
                   </td>
-                  <td class="diff-line-content">{line.line}</td>
+                  <td class="diff-line-content">
+                    {#if highlighting}
+                      {#if line.type === "addition" && highlighting.new}
+                        {@html highlighting.new[line.lineNo - 1]}
+                      {:else if line.type === "context" && highlighting.new}
+                        {@html highlighting.new[line.lineNoNew - 1]}
+                      {:else if line.type === "deletion" && highlighting.old}
+                        {@html highlighting.old[line.lineNo - 1]}
+                      {/if}
+                    {:else}
+                      {line.line}
+                    {/if}
+                  </td>
                 </tr>
               {/each}
             {/each}
diff --git a/src/views/projects/Commit.svelte b/src/views/projects/Commit.svelte
index 271e54d48..69cbece04 100644
--- a/src/views/projects/Commit.svelte
+++ b/src/views/projects/Commit.svelte
@@ -1,5 +1,5 @@
 <script lang="ts">
-  import type { Commit, BaseUrl, Project } from "@httpd-client";
+  import type { BaseUrl, Commit, Project } from "@httpd-client";
 
   import { formatCommit } from "@app/lib/utils";
 
@@ -70,8 +70,9 @@
       <CommitAuthorship {header} />
     </div>
     <Changeset
-      projectId={project.id}
       {baseUrl}
+      projectId={project.id}
+      files={commit.files}
       diff={commit.diff}
       revision={commit.commit.id} />
   </div>
diff --git a/src/views/projects/Patch.svelte b/src/views/projects/Patch.svelte
index cf3e6f454..249960d2e 100644
--- a/src/views/projects/Patch.svelte
+++ b/src/views/projects/Patch.svelte
@@ -547,9 +547,10 @@
       {#if view.name === "diff"}
         <div style:margin-top="1rem">
           <Changeset
-            projectId={project.id}
             {baseUrl}
+            projectId={project.id}
             revision={view.toCommit}
+            files={view.files}
             diff={view.diff} />
         </div>
       {:else if view.name === "activity"}
@@ -585,8 +586,9 @@
       {:else if view.name === "files"}
         <div style:margin-top="1rem">
           <Changeset
-            projectId={project.id}
             {baseUrl}
+            projectId={project.id}
+            revision={view.oid}
             files={view.files}
             diff={view.diff} />
         </div>
diff --git a/src/views/projects/router.ts b/src/views/projects/router.ts
index 9a5628469..403721c69 100644
--- a/src/views/projects/router.ts
+++ b/src/views/projects/router.ts
@@ -9,6 +9,7 @@ import type {
   CommitBlob,
   CommitHeader,
   Diff,
+  DiffBlob,
   Issue,
   IssueState,
   Patch,
@@ -133,7 +134,6 @@ export type ProjectLoadedRoute =
       params: {
         baseUrl: BaseUrl;
         project: Project;
-
         commit: Commit;
       };
     }
@@ -151,7 +151,6 @@ export type ProjectLoadedRoute =
       params: {
         baseUrl: BaseUrl;
         project: Project;
-
         issues: Issue[];
         state: IssueState["status"];
       };
@@ -168,7 +167,6 @@ export type ProjectLoadedRoute =
       params: {
         baseUrl: BaseUrl;
         project: Project;
-
         patches: Patch[];
         state: PatchState["status"];
       };
@@ -178,7 +176,6 @@ export type ProjectLoadedRoute =
       params: {
         baseUrl: BaseUrl;
         project: Project;
-
         patch: Patch;
         view: PatchView;
       };
@@ -196,6 +193,7 @@ export type PatchView =
   | {
       name: "commits" | "files";
       revision: string;
+      oid: string;
       diff: Diff;
       commits: CommitHeader[];
       files: Record<string, CommitBlob>;
@@ -203,6 +201,7 @@ export type PatchView =
   | {
       name: "diff";
       diff: Diff;
+      files: Record<string, DiffBlob>;
       fromCommit: string;
       toCommit: string;
     };
@@ -547,6 +546,7 @@ async function loadPatchView(
       view = {
         name: route.view?.name,
         revision: revision.id,
+        oid: revision.oid,
         diff,
         commits,
         files,
@@ -555,13 +555,13 @@ async function loadPatchView(
     }
     case "diff": {
       const { fromCommit, toCommit } = route.view;
-      const { diff } = await api.project.getDiff(
+      const { diff, files } = await api.project.getDiff(
         route.project,
         fromCommit,
         toCommit,
       );
 
-      view = { name: "diff", fromCommit, toCommit, diff };
+      view = { name: "diff", fromCommit, toCommit, files, diff };
       break;
     }
   }
diff --git a/tests/support/heartwood-version b/tests/support/heartwood-version
index cadf87a38..2c4deac79 100644
--- a/tests/support/heartwood-version
+++ b/tests/support/heartwood-version
@@ -1 +1 @@
-5acfffb352a47e052673f7ecc0c87653bc6c8ec4
+2011f2b06e7207498aa084a25583c3c96c782c2d