src/terminal can build into a minimal wasm library, I think

build.zig

@@ -52,6 +52,21 @@ pub fn build(b: *std.build.Builder) !void {
         if (tracy) try tracylib.link(b, exe, target);
     }
 
+    // term.wasm
+    {
+        const wasm = b.addSharedLibrary(
+            "ghostty-term",
+            "src/terminal/main_wasm.zig",
+            .{ .unversioned = {} },
+        );
+        wasm.setTarget(.{ .cpu_arch = .wasm32, .os_tag = .freestanding });
+        wasm.setBuildMode(mode);
+        wasm.setOutputDir("zig-out");
+
+        const step = b.step("term-wasm", "Build the terminal.wasm library");
+        step.dependOn(&wasm.step);
+    }
+
     // Run
     {
         // Build our run step, which runs the main app by default, but will

nix/devshell.nix

@@ -8,6 +8,8 @@
 , tracy
 , vulkan-loader
 , vttest
+, wabt
+, wasmtime
 , wraptest
 , zig
 
@@ -48,6 +50,10 @@ in mkShell rec {
     tracy
     vttest
     wraptest
+
+    # wasm
+    wabt
+    wasmtime
   ];
 
   buildInputs = [

src/terminal/c_api.zig

@@ -0,0 +1,27 @@
+// This is the C-ABI API for the terminal package. This isn't used
+// by other Zig programs but by C or WASM interfacing.
+
+const std = @import("std");
+const builtin = @import("builtin");
+const Allocator = std.mem.Allocator;
+const Terminal = @import("main.zig").Terminal;
+
+// The allocator that we want to use.
+const alloc = if (builtin.target.isWasm())
+    std.heap.page_allocator
+else
+    std.heap.c_allocator;
+
+export fn terminal_new(cols: usize, rows: usize) ?*Terminal {
+    const term = Terminal.init(alloc, cols, rows) catch return null;
+    const result = alloc.create(Terminal) catch return null;
+    result.* = term;
+    return result;
+}
+
+export fn terminal_free(ptr: ?*Terminal) void {
+    if (ptr) |v| {
+        v.deinit(alloc);
+        alloc.destroy(v);
+    }
+}

src/terminal/main.zig

@@ -1,3 +1,5 @@
+const builtin = @import("builtin");
+
 const stream = @import("stream.zig");
 const ansi = @import("ansi.zig");
 const csi = @import("csi.zig");
@@ -21,8 +23,6 @@ pub const EraseLine = csi.EraseLine;
 pub const TabClear = csi.TabClear;
 pub const Attribute = sgr.Attribute;
 
-// Not exported because they're just used for tests.
-
 test {
     _ = ansi;
     _ = color;

src/terminal/main_wasm.zig

@@ -0,0 +1,4 @@
+// This is the main file for the WASM module. The WASM module just
+// imports the C API.
+
+pub usingnamespace @import("c_api.zig");