diff --git a/README.md b/README.md
index ba7c84ccc24667a3771a2d524fa6c9158ca7c09b..0710ecd57d6622e1d192d29ea46f0e2c23e1737c 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@
 ![loc](https://sloc.xyz/github/nektro/zig-pek)
 [![license](https://img.shields.io/github/license/nektro/zig-pek.svg)](https://github.com/nektro/zig-pek/blob/master/LICENSE)
 [![nektro @ github sponsors](https://img.shields.io/badge/sponsors-nektro-purple?logo=github)](https://github.com/sponsors/nektro)
-[![Zig](https://img.shields.io/badge/Zig-0.14-f7a41d)](https://ziglang.org/)
+[![Zig](https://img.shields.io/badge/Zig-0.15-f7a41d)](https://ziglang.org/)
 [![Zigmod](https://img.shields.io/badge/Zigmod-latest-f7a41d)](https://github.com/nektro/zigmod)
 
 A comptime HTML preprocessor with a builtin template engine for Zig.
diff --git a/src/lib.zig b/src/lib.zig
index 88e6ccdc31ac9dc3815888d4813bcf1ac91ebbea..0c901ca043466dcc369b7bfbb8534bdbf5d8eea1 100644
--- a/src/lib.zig
+++ b/src/lib.zig
@@ -40,7 +40,7 @@ pub fn compileInner(alloc: std.mem.Allocator, writer: anytype, comptime value: a
     try do(alloc, writer, value, data, data, opts);
 }
 
-pub const Writer = std.ArrayList(u8).Writer;
+pub const Writer = *std.Io.Writer;
 
 fn do(alloc: std.mem.Allocator, writer: anytype, comptime value: astgen.Value, data: anytype, ctx: anytype, comptime opts: DoOptions) anyerror!void {
     comptime var skipindent = false;
@@ -297,33 +297,33 @@ fn doInner(alloc: std.mem.Allocator, writer: anytype, comptime value: astgen.Val
         .function => |v| {
             if (!v.raw and @hasDecl(opts.Ctx, "pek_" ++ v.name)) {
                 const func = @field(opts.Ctx, "pek_" ++ v.name);
-                var list = std.ArrayList(u8).init(alloc);
+                var list = std.Io.Writer.Allocating.init(alloc);
                 defer list.deinit();
                 comptime var types: [v.args.len]type = @splat(void);
                 inline for (v.args, &types) |arg, *T| T.* = ResolveArg(arg, @TypeOf(data), @TypeOf(ctx));
                 var args: std.meta.Tuple(&types) = undefined;
                 inline for (v.args, 0..) |arg, i| args[i] = try resolveArg(arg, alloc, data, ctx, opts);
-                try @call(.auto, func, .{ alloc, list.writer() } ++ args);
+                try @call(.auto, func, .{ alloc, &list.writer } ++ args);
                 try writeReplacementString(writer, v.raw, opts.escaped, try list.toOwnedSlice());
                 return;
             }
             if (v.raw and @hasDecl(opts.Ctx, "pek__" ++ v.name)) {
                 const func = @field(opts.Ctx, "pek__" ++ v.name);
-                var list = std.ArrayList(u8).init(alloc);
+                var list = std.Io.Writer.Allocating.init(alloc);
                 defer list.deinit();
                 const Tup = @typeInfo(@TypeOf(func)).@"fn".params[3].type.?;
                 if (@typeInfo(Tup).@"struct".fields.len == 0) {
                     // edge case branch because 'struct {}' is counted as a non-tuple
-                    try @call(.auto, func, .{ alloc, list.writer(), opts, Tup{} });
-                    try writeReplacementString(writer, v.raw, opts.escaped, list.items);
+                    try @call(.auto, func, .{ alloc, &list.writer, opts, Tup{} });
+                    try writeReplacementString(writer, v.raw, opts.escaped, list.written());
                     return;
                 }
                 comptime var types: [v.args.len]type = @splat(void);
                 inline for (v.args, &types) |arg, *T| T.* = ResolveArg(arg, @TypeOf(data), @TypeOf(ctx));
                 var args: std.meta.Tuple(&types) = undefined;
                 inline for (v.args, 0..) |arg, i| args[i] = try resolveArg(arg, alloc, data, ctx, opts);
-                try @call(.auto, func, .{ alloc, list.writer(), opts, args });
-                try writeReplacementString(writer, v.raw, opts.escaped, list.items);
+                try @call(.auto, func, .{ alloc, &list.writer, opts, args });
+                try writeReplacementString(writer, v.raw, opts.escaped, list.written());
                 return;
             }
             if (v.raw and @hasDecl(opts.Ctx, "pek_" ++ v.name)) {
@@ -352,11 +352,11 @@ fn resolveArg(comptime arg: astgen.Arg, alloc: std.mem.Allocator, data: anytype,
         .lookup => |av| search(av, ctx),
         .int => |av| av,
         .value => |av| {
-            var list = std.ArrayList(u8).init(alloc);
+            var list = std.Io.Writer.Allocating.init(alloc);
             comptime var newopts = opts;
             newopts.escaped = false;
-            try do(alloc, list.writer(), astgen.Value{ .body = av }, data, ctx, newopts);
-            return list.items;
+            try do(alloc, &list.writer, astgen.Value{ .body = av }, data, ctx, newopts);
+            return list.written();
         },
     };
 }