diff --git a/src/main/java/be/seeseepuff/webgit/service/GitService.java b/src/main/java/be/seeseepuff/webgit/service/GitService.java
new file mode 100644
index 0000000..fef468e
--- /dev/null
+++ b/src/main/java/be/seeseepuff/webgit/service/GitService.java
@@ -0,0 +1,189 @@
+package be.seeseepuff.webgit.service;
+
+import be.seeseepuff.webgit.config.WebgitProperties;
+import lombok.RequiredArgsConstructor;
+import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.api.errors.GitAPIException;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.lib.StoredConfig;
+import org.eclipse.jgit.storage.file.FileRepositoryBuilder;
+import org.springframework.stereotype.Service;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.stream.Stream;
+
+@Service
+@RequiredArgsConstructor
+public class GitService
+{
+	private final WebgitProperties properties;
+
+	public void cloneRepository(String url, String name) throws GitAPIException, IOException
+	{
+		Path worktree = properties.getWorktreePath().resolve(name);
+		Path gitDir = properties.getGitDirPath().resolve(name);
+
+		Files.createDirectories(worktree);
+		Files.createDirectories(gitDir);
+
+		try (Git git = Git.cloneRepository()
+			.setURI(url)
+			.setDirectory(worktree.toFile())
+			.setGitDir(gitDir.toFile())
+			.call())
+		{
+			// clone complete
+		}
+	}
+
+	public List<String> listRepositories() throws IOException
+	{
+		Path gitDirBase = properties.getGitDirPath();
+		if (!Files.exists(gitDirBase))
+			return List.of();
+
+		try (Stream<Path> dirs = Files.list(gitDirBase))
+		{
+			return dirs
+				.filter(Files::isDirectory)
+				.map(p -> p.getFileName().toString())
+				.sorted()
+				.toList();
+		}
+	}
+
+	public List<String> listBranches(String name) throws IOException, GitAPIException
+	{
+		try (Git git = openRepository(name))
+		{
+			return git.branchList()
+				.call()
+				.stream()
+				.map(Ref::getName)
+				.map(ref -> ref.startsWith("refs/heads/") ? ref.substring("refs/heads/".length()) : ref)
+				.toList();
+		}
+	}
+
+	public String getCurrentBranch(String name) throws IOException
+	{
+		try (Git git = openRepository(name))
+		{
+			return git.getRepository().getBranch();
+		}
+	}
+
+	public void checkoutBranch(String name, String branch) throws IOException, GitAPIException
+	{
+		try (Git git = openRepository(name))
+		{
+			git.checkout()
+				.setName(branch)
+				.call();
+		}
+	}
+
+	public void createAndCheckoutBranch(String name, String branch) throws IOException, GitAPIException
+	{
+		try (Git git = openRepository(name))
+		{
+			git.checkout()
+				.setCreateBranch(true)
+				.setName(branch)
+				.call();
+		}
+	}
+
+	public List<String> getModifiedFiles(String name) throws IOException, GitAPIException
+	{
+		try (Git git = openRepository(name))
+		{
+			var status = git.status().call();
+			return Stream.of(
+					status.getModified().stream(),
+					status.getUntracked().stream(),
+					status.getMissing().stream()
+				)
+				.flatMap(s -> s)
+				.sorted()
+				.toList();
+		}
+	}
+
+	public List<String> getStagedFiles(String name) throws IOException, GitAPIException
+	{
+		try (Git git = openRepository(name))
+		{
+			var status = git.status().call();
+			return Stream.of(
+					status.getAdded().stream(),
+					status.getChanged().stream(),
+					status.getRemoved().stream()
+				)
+				.flatMap(s -> s)
+				.sorted()
+				.toList();
+		}
+	}
+
+	public void stageFiles(String name, List<String> files) throws IOException, GitAPIException
+	{
+		try (Git git = openRepository(name))
+		{
+			for (String file : files)
+			{
+				if (Files.exists(properties.getWorktreePath().resolve(name).resolve(file)))
+				{
+					git.add().addFilepattern(file).call();
+				}
+				else
+				{
+					git.rm().addFilepattern(file).call();
+				}
+			}
+		}
+	}
+
+	public void commit(String name, String message) throws IOException, GitAPIException
+	{
+		try (Git git = openRepository(name))
+		{
+			git.commit()
+				.setMessage(message)
+				.call();
+		}
+	}
+
+	public void push(String name) throws IOException, GitAPIException
+	{
+		try (Git git = openRepository(name))
+		{
+			git.push().call();
+		}
+	}
+
+	public void pull(String name) throws IOException, GitAPIException
+	{
+		try (Git git = openRepository(name))
+		{
+			git.pull().call();
+		}
+	}
+
+	private Git openRepository(String name) throws IOException
+	{
+		Path gitDir = properties.getGitDirPath().resolve(name);
+		Path worktree = properties.getWorktreePath().resolve(name);
+
+		Repository repo = new FileRepositoryBuilder()
+			.setGitDir(gitDir.toFile())
+			.setWorkTree(worktree.toFile())
+			.build();
+
+		return new Git(repo);
+	}
+}
diff --git a/src/test/java/be/seeseepuff/webgit/service/GitServiceTest.java b/src/test/java/be/seeseepuff/webgit/service/GitServiceTest.java
new file mode 100644
index 0000000..c5c0846
--- /dev/null
+++ b/src/test/java/be/seeseepuff/webgit/service/GitServiceTest.java
@@ -0,0 +1,219 @@
+package be.seeseepuff.webgit.service;
+
+import be.seeseepuff.webgit.config.WebgitProperties;
+import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.api.errors.GitAPIException;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class GitServiceTest
+{
+	@TempDir
+	Path tempDir;
+
+	private Path worktreePath;
+	private Path gitDirPath;
+	private Path bareRemote;
+	private GitService gitService;
+
+	@BeforeEach
+	void setUp() throws GitAPIException
+	{
+		worktreePath = tempDir.resolve("worktrees");
+		gitDirPath = tempDir.resolve("gitdirs");
+		bareRemote = tempDir.resolve("remote.git");
+
+		// Create a bare remote with an initial commit so we have something to clone
+		Git.init().setDirectory(bareRemote.toFile()).setBare(true).call().close();
+		// Create a temp working copy to make an initial commit
+		Path tmpWork = tempDir.resolve("tmp-work");
+		try (Git tmp = Git.cloneRepository()
+			.setURI(bareRemote.toUri().toString())
+			.setDirectory(tmpWork.toFile())
+			.call())
+		{
+			Files.writeString(tmpWork.resolve("README.md"), "# Test");
+			tmp.add().addFilepattern("README.md").call();
+			tmp.commit().setMessage("Initial commit").call();
+			tmp.push().call();
+		}
+		catch (IOException e)
+		{
+			throw new RuntimeException(e);
+		}
+
+		WebgitProperties props = new WebgitProperties();
+		props.setWorktreePath(worktreePath);
+		props.setGitDirPath(gitDirPath);
+		gitService = new GitService(props);
+	}
+
+	@Test
+	void cloneCreatesWorktreeAndGitDir() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+
+		assertTrue(Files.exists(worktreePath.resolve("myrepo/README.md")));
+		assertTrue(Files.exists(gitDirPath.resolve("myrepo/HEAD")));
+	}
+
+	@Test
+	void listRepositoriesReturnsEmptyWhenNothingCloned() throws IOException
+	{
+		List<String> repos = gitService.listRepositories();
+		assertTrue(repos.isEmpty());
+	}
+
+	@Test
+	void listRepositoriesReturnsClonedRepos() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "alpha");
+		gitService.cloneRepository(bareRemote.toUri().toString(), "beta");
+
+		List<String> repos = gitService.listRepositories();
+		assertEquals(List.of("alpha", "beta"), repos);
+	}
+
+	@Test
+	void listBranchesReturnsDefaultBranch() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+
+		List<String> branches = gitService.listBranches("myrepo");
+		assertEquals(1, branches.size());
+		assertTrue(branches.contains("master") || branches.contains("main"));
+	}
+
+	@Test
+	void getCurrentBranchReturnsDefaultBranch() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+
+		String branch = gitService.getCurrentBranch("myrepo");
+		assertTrue("master".equals(branch) || "main".equals(branch));
+	}
+
+	@Test
+	void createAndCheckoutBranchCreatesNewBranch() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+		gitService.createAndCheckoutBranch("myrepo", "feature-x");
+
+		assertEquals("feature-x", gitService.getCurrentBranch("myrepo"));
+		assertTrue(gitService.listBranches("myrepo").contains("feature-x"));
+	}
+
+	@Test
+	void checkoutBranchSwitchesBranch() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+		String defaultBranch = gitService.getCurrentBranch("myrepo");
+
+		gitService.createAndCheckoutBranch("myrepo", "feature-y");
+		assertEquals("feature-y", gitService.getCurrentBranch("myrepo"));
+
+		gitService.checkoutBranch("myrepo", defaultBranch);
+		assertEquals(defaultBranch, gitService.getCurrentBranch("myrepo"));
+	}
+
+	@Test
+	void getModifiedFilesDetectsChanges() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+
+		// Modify an existing file
+		Files.writeString(worktreePath.resolve("myrepo/README.md"), "# Changed");
+		// Create a new untracked file
+		Files.writeString(worktreePath.resolve("myrepo/newfile.txt"), "hello");
+
+		List<String> modified = gitService.getModifiedFiles("myrepo");
+		assertTrue(modified.contains("README.md"));
+		assertTrue(modified.contains("newfile.txt"));
+	}
+
+	@Test
+	void getModifiedFilesDetectsDeletedFiles() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+
+		Files.delete(worktreePath.resolve("myrepo/README.md"));
+
+		List<String> modified = gitService.getModifiedFiles("myrepo");
+		assertTrue(modified.contains("README.md"));
+	}
+
+	@Test
+	void getStagedFilesReturnsEmpty() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+
+		List<String> staged = gitService.getStagedFiles("myrepo");
+		assertTrue(staged.isEmpty());
+	}
+
+	@Test
+	void stageFilesAndGetStagedFiles() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+		Files.writeString(worktreePath.resolve("myrepo/newfile.txt"), "hello");
+
+		gitService.stageFiles("myrepo", List.of("newfile.txt"));
+
+		List<String> staged = gitService.getStagedFiles("myrepo");
+		assertTrue(staged.contains("newfile.txt"));
+	}
+
+	@Test
+	void stageDeletedFile() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+		Files.delete(worktreePath.resolve("myrepo/README.md"));
+
+		gitService.stageFiles("myrepo", List.of("README.md"));
+
+		List<String> staged = gitService.getStagedFiles("myrepo");
+		assertTrue(staged.contains("README.md"));
+		assertTrue(gitService.getModifiedFiles("myrepo").isEmpty());
+	}
+
+	@Test
+	void commitCreatesCommit() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+		Files.writeString(worktreePath.resolve("myrepo/newfile.txt"), "hello");
+		gitService.stageFiles("myrepo", List.of("newfile.txt"));
+
+		gitService.commit("myrepo", "Add newfile");
+
+		// After committing, staged should be empty
+		assertTrue(gitService.getStagedFiles("myrepo").isEmpty());
+		assertTrue(gitService.getModifiedFiles("myrepo").isEmpty());
+	}
+
+	@Test
+	void pushSendsToRemote() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+		Files.writeString(worktreePath.resolve("myrepo/newfile.txt"), "hello");
+		gitService.stageFiles("myrepo", List.of("newfile.txt"));
+		gitService.commit("myrepo", "Add newfile");
+
+		assertDoesNotThrow(() -> gitService.push("myrepo"));
+	}
+
+	@Test
+	void pullFetchesFromRemote() throws GitAPIException, IOException
+	{
+		gitService.cloneRepository(bareRemote.toUri().toString(), "myrepo");
+
+		assertDoesNotThrow(() -> gitService.pull("myrepo"));
+	}
+}