diff --git a/build.zig b/build.zig
index 2775042a3..d0b4da0d0 100644
--- a/build.zig
+++ b/build.zig
@@ -1,4 +1,5 @@
 const std = @import("std");
+const fs = std.fs;
 const Builder = std.build.Builder;
 const LibExeObjStep = std.build.LibExeObjStep;
 const glfw = @import("vendor/mach/glfw/build.zig");
@@ -15,6 +16,11 @@ pub fn build(b: *std.build.Builder) !void {
         "tracy",
         "Enable Tracy integration (default true in Debug)",
     ) orelse (mode == .Debug);
+    const conformance = b.option(
+        []const u8,
+        "conformance",
+        "Name of the conformance app to run with 'run' option.",
+    );
 
     const exe_options = b.addOptions();
     exe_options.addOption(bool, "tracy_enabled", tracy);
@@ -50,8 +56,18 @@ pub fn build(b: *std.build.Builder) !void {
     // exe.addIncludeDir("vendor/stb");
     // exe.addCSourceFile("src/stb/stb.c", &.{});
 
-    const run_cmd = exe.run();
-    run_cmd.step.dependOn(b.getInstallStep());
+    // Conformance apps
+    var conformance_exes = try conformanceSteps(b, target, mode);
+    defer conformance_exes.deinit();
+
+    // Build our run step, which runs the main app by default, but will
+    // run a conformance app if `-Dconformance` is set.
+    const run_exe = if (conformance) |name|
+        conformance_exes.get(name) orelse return error.InvalidConformance
+    else
+        exe;
+    const run_cmd = run_exe.run();
+    run_cmd.step.dependOn(&run_exe.step);
     if (b.args) |args| {
         run_cmd.addArgs(args);
     }
@@ -68,3 +84,48 @@ pub fn build(b: *std.build.Builder) !void {
     lib_tests.addCSourceFile("vendor/glad/src/gl.c", &.{});
     test_step.dependOn(&lib_tests.step);
 }
+
+fn conformanceSteps(
+    b: *std.build.Builder,
+    target: std.zig.CrossTarget,
+    mode: std.builtin.Mode,
+) !std.StringHashMap(*LibExeObjStep) {
+    var map = std.StringHashMap(*LibExeObjStep).init(b.allocator);
+
+    // Open the directory ./conformance
+    const c_dir_path = root() ++ "/conformance";
+    var c_dir = try fs.openDirAbsolute(c_dir_path, .{ .iterate = true });
+    defer c_dir.close();
+
+    // Go through and add each as a step
+    var c_dir_it = c_dir.iterate();
+    while (try c_dir_it.next()) |entry| {
+        // Get the index of the last '.' so we can strip the extension.
+        const index = std.mem.lastIndexOfScalar(u8, entry.name, '.') orelse continue;
+        if (index == 0) continue;
+
+        // Name of the conformance app and full path to the entrypoint.
+        const name = entry.name[0..index];
+        const path = try fs.path.join(b.allocator, &[_][]const u8{
+            c_dir_path,
+            entry.name,
+        });
+
+        // Executable builder. We install all conformance tests so that
+        // `zig build` verifies they work.
+        const c_exe = b.addExecutable(name, path);
+        c_exe.setTarget(target);
+        c_exe.setBuildMode(mode);
+        c_exe.install();
+
+        // Store the mapping
+        try map.put(name, c_exe);
+    }
+
+    return map;
+}
+
+/// Path to the directory with the build.zig.
+fn root() []const u8 {
+    return std.fs.path.dirname(@src().file) orelse unreachable;
+}
diff --git a/conformance/ansi_ri.zig b/conformance/ansi_ri.zig
new file mode 100644
index 000000000..991804295
--- /dev/null
+++ b/conformance/ansi_ri.zig
@@ -0,0 +1,12 @@
+//! Reverse Index (RI) - ESC M
+const std = @import("std");
+
+pub fn main() !void {
+    const stdout = std.io.getStdOut().writer();
+    try stdout.print("A\nB\nC", .{});
+    try stdout.print("\x1BM", .{});
+    try stdout.print("D\n\n", .{});
+
+    // const stdin = std.io.getStdIn().reader();
+    // _ = try stdin.readByte();
+}
diff --git a/conformance/ansi_ri_top.zig b/conformance/ansi_ri_top.zig
new file mode 100644
index 000000000..a8094d2bd
--- /dev/null
+++ b/conformance/ansi_ri_top.zig
@@ -0,0 +1,10 @@
+//! Reverse Index (RI) - ESC M at the top of the screen.
+const std = @import("std");
+
+pub fn main() !void {
+    const stdout = std.io.getStdOut().writer();
+    try stdout.print("\x1B[H", .{}); // move to top-left
+    try stdout.print("\x1B[J", .{}); // clear screen
+    try stdout.print("\x1BM", .{});
+    try stdout.print("D\n", .{});
+}