diff --git a/src/engine.zig b/src/engine.zig
index 901215d..76bbfc8 100644
--- a/src/engine.zig
+++ b/src/engine.zig
@@ -42,7 +42,8 @@ pub fn loadEnv(
     }
     var loop = try Loop.init(alloc);
     defer loop.deinit();
-    var js_env = try Env.init(alloc, &loop, userctx);
+    var js_env: public.Env = undefined;
+    Env.init(&js_env, alloc, &loop, userctx);
     defer js_env.deinit();
 
     // load APIs in JS env
diff --git a/src/engines/v8/v8.zig b/src/engines/v8/v8.zig
index 16f3c39..7cff259 100644
--- a/src/engines/v8/v8.zig
+++ b/src/engines/v8/v8.zig
@@ -80,7 +80,7 @@ pub const VM = struct {
 };
 
 pub const Env = struct {
-    nat_ctx: *NativeContext,
+    nat_ctx: NativeContext,
 
     isolate: v8.Isolate,
     isolate_params: v8.CreateParams,
@@ -94,10 +94,11 @@ pub const Env = struct {
     }
 
     pub fn init(
+        self: *Env,
         alloc: std.mem.Allocator,
         loop: *public.Loop,
         userctx: ?public.UserContext,
-    ) anyerror!Env {
+    ) void {
 
         // v8 values
         // ---------
@@ -117,13 +118,14 @@ pub const Env = struct {
         // ObjectTemplate for the global namespace
         const globals = v8.FunctionTemplate.initDefault(isolate);
 
-        return Env{
-            .nat_ctx = try NativeContext.init(alloc, loop, userctx),
+        self.* = Env{
+            .nat_ctx = undefined,
             .isolate_params = params,
             .isolate = isolate,
             .hscope = hscope,
             .globals = globals,
         };
+        NativeContext.init(&self.nat_ctx, alloc, loop, userctx);
     }
 
     pub fn deinit(self: *Env) void {
@@ -155,9 +157,9 @@ pub const Env = struct {
     }
 
     // load user-defined Types into Javascript environement
-    pub fn load(self: Env, js_types: []usize) anyerror!void {
+    pub fn load(self: *Env, js_types: []usize) anyerror!void {
         var tpls: [gen.Types.len]TPL = undefined;
-        try gen.load(self.nat_ctx, self.isolate, self.globals, TPL, &tpls);
+        try gen.load(&self.nat_ctx, self.isolate, self.globals, TPL, &tpls);
         for (tpls, 0..) |tpl, i| {
             js_types[i] = @intFromPtr(tpl.tpl.handle);
         }
@@ -185,8 +187,8 @@ pub const Env = struct {
             // TODO: is there a better way to do it at the Template level?
             // see https://github.com/Browsercore/jsruntime-lib/issues/128
             if (T_refl.proto_index) |proto_index| {
-                const cstr_tpl = getTpl(self.nat_ctx, i);
-                const proto_tpl = getTpl(self.nat_ctx, proto_index);
+                const cstr_tpl = getTpl(&self.nat_ctx, i);
+                const proto_tpl = getTpl(&self.nat_ctx, proto_index);
                 const cstr_obj = cstr_tpl.getFunction(js_ctx).toObject();
                 const proto_obj = proto_tpl.getFunction(js_ctx).toObject();
                 _ = cstr_obj.setPrototype(js_ctx, proto_obj);
@@ -225,7 +227,7 @@ pub const Env = struct {
         return self.js_ctx.?.getGlobal();
     }
 
-    pub fn bindGlobal(self: Env, obj: anytype) anyerror!void {
+    pub fn bindGlobal(self: *Env, obj: anytype) anyerror!void {
         const T_refl = comptime gen.getType(@TypeOf(obj));
         if (!comptime refl.isGlobalType(T_refl.T)) return error.notGlobalType;
         const T = T_refl.Self();
@@ -252,7 +254,7 @@ pub const Env = struct {
 
         _ = try bindObjectNativeAndJS(
             self.nat_ctx.alloc,
-            self.nat_ctx,
+            &self.nat_ctx,
             T_refl,
             nat_obj_ptr,
             self.js_ctx.?.getGlobal(),
diff --git a/src/interfaces.zig b/src/interfaces.zig
index 1d7db3c..7de3a36 100644
--- a/src/interfaces.zig
+++ b/src/interfaces.zig
@@ -54,15 +54,15 @@ pub fn Env(
     assertDecl(T, "engine", fn () public.engineType);
 
     // init()
-    assertDecl(T, "init", fn (alloc: std.mem.Allocator, loop: *public.Loop, userctx: ?public.UserContext) anyerror!T);
+    assertDecl(T, "init", fn (self: *T, alloc: std.mem.Allocator, loop: *public.Loop, userctx: ?public.UserContext) void);
 
     // deinit()
     assertDecl(T, "deinit", fn (self: *T) void);
 
     // load() native apis into js templates
-    assertDecl(T, "load", fn (self: T, js_types: []usize) anyerror!void);
+    assertDecl(T, "load", fn (self: *T, js_types: []usize) anyerror!void);
 
-    assertDecl(T, "bindGlobal", fn (self: T, ob: anytype) anyerror!void);
+    assertDecl(T, "bindGlobal", fn (self: *T, ob: anytype) anyerror!void);
 
     assertDecl(T, "setUserContext", fn (
         self: *T,
diff --git a/src/native_context.zig b/src/native_context.zig
index 8cb88b8..7fb7a71 100644
--- a/src/native_context.zig
+++ b/src/native_context.zig
@@ -33,8 +33,7 @@ pub const NativeContext = struct {
 
     pub const JSObjects = std.AutoHashMapUnmanaged(usize, usize);
 
-    pub fn init(alloc: std.mem.Allocator, loop: *Loop, userctx: ?UserContext) !*NativeContext {
-        const self = try alloc.create(NativeContext);
+    pub fn init(self: *NativeContext, alloc: std.mem.Allocator, loop: *Loop, userctx: ?UserContext) void {
         self.* = .{
             .alloc = alloc,
             .loop = loop,
@@ -42,7 +41,6 @@ pub const NativeContext = struct {
             .js_objs = JSObjects{},
             .nat_objs = NatObjects{},
         };
-        return self;
     }
 
     pub fn stop(self: *NativeContext) void {
@@ -58,7 +56,7 @@ pub const NativeContext = struct {
         self.js_types = js_types;
     }
 
-    pub fn getType(self: NativeContext, comptime T: type, index: usize) *T {
+    pub fn getType(self: *const NativeContext, comptime T: type, index: usize) *T {
         std.debug.assert(self.js_types != null);
         const t = self.js_types.?[index];
         return @as(*T, @ptrFromInt(t));