diff --git a/examples/app/basic.zig b/examples/app/basic.zig
index d59b062..e41ccfc 100644
--- a/examples/app/basic.zig
+++ b/examples/app/basic.zig
@@ -57,7 +57,7 @@ const SimpleEndpoint = struct {
             .{ context.db_connection, e.some_data, arena.ptr, thread_id },
         );
         try r.sendBody(response_text);
-        std.Thread.sleep(std.time.ns_per_ms * 300);
+        std.posix.nanosleep(0, 300 * std.time.ns_per_ms);
     }
 };
 
diff --git a/examples/http_params/http_params.zig b/examples/http_params/http_params.zig
index 512ec22..bcfc228 100644
--- a/examples/http_params/http_params.zig
+++ b/examples/http_params/http_params.zig
@@ -17,7 +17,9 @@ pub const std_options: std.Options = .{
 
 // We send ourselves a request
 fn makeRequest(a: std.mem.Allocator, url: []const u8) !void {
-    var http_client: std.http.Client = .{ .allocator = a };
+    var thread: std.Io.Threaded = .init(a);
+    defer thread.deinit();
+    var http_client: std.http.Client = .{ .allocator = a, .io = thread.io()  };
     defer http_client.deinit();
 
     const response = try http_client.fetch(.{
diff --git a/src/request.zig b/src/request.zig
index 8ddb904..572750c 100644
--- a/src/request.zig
+++ b/src/request.zig
@@ -354,13 +354,13 @@ pub fn _internal_sendError(self: *const Request, err: anyerror, err_trace: ?std.
     // TODO: let's hope 20k is enough. Maybe just really allocate here
     self.h.*.status = errorcode_num;
     var buf: [20 * 1024]u8 = undefined;
-    var writer = std.io.Writer.fixed(&buf);
+    var writer = std.Io.Writer.fixed(&buf);
     try writer.print("ERROR: {any}\n\n", .{err});
 
+    
     if (err_trace) |trace| {
-        const debugInfo = try std.debug.getSelfDebugInfo();
-        const ttyConfig: std.io.tty.Config = .no_color;
-        try std.debug.writeStackTrace(trace, &writer, debugInfo, ttyConfig);
+        const ttyConfig: std.Io.tty.Config = .no_color;
+        try std.debug.writeStackTrace(&trace, &writer, ttyConfig);
     }
 
     try self.sendBody(writer.buffered());
diff --git a/src/tests/test_auth.zig b/src/tests/test_auth.zig
index ec87be2..67bf772 100644
--- a/src/tests/test_auth.zig
+++ b/src/tests/test_auth.zig
@@ -111,7 +111,9 @@ const ClientAuthReqHeaderFields = struct {
 };
 
 fn makeRequest(a: std.mem.Allocator, url: []const u8, auth: ?ClientAuthReqHeaderFields) !void {
-    var http_client: std.http.Client = .{ .allocator = a };
+    var thread: std.Io.Threaded = .init(a);
+    defer thread.deinit();
+    var http_client: std.http.Client = .{ .allocator = a, .io = thread.io() };
     defer http_client.deinit();
 
     var auth_buf: [256]u8 = undefined;
@@ -154,7 +156,7 @@ pub const Endpoint = struct {
     pub fn get(_: *Endpoint, r: zap.Request) !void {
         r.sendBody(HTTP_RESPONSE) catch return;
         received_response = HTTP_RESPONSE;
-        std.Thread.sleep(1 * std.time.ns_per_s);
+        std.posix.nanosleep(1,0);
         zap.stop();
     }
 
@@ -162,7 +164,7 @@ pub const Endpoint = struct {
         r.setStatus(.unauthorized);
         r.sendBody("UNAUTHORIZED ACCESS") catch return;
         received_response = "UNAUTHORIZED";
-        std.Thread.sleep(1 * std.time.ns_per_s);
+        std.posix.nanosleep(1, 0);
         zap.stop();
     }
 };
diff --git a/src/tests/test_http_params.zig b/src/tests/test_http_params.zig
index eefb76e..5a3db60 100644
--- a/src/tests/test_http_params.zig
+++ b/src/tests/test_http_params.zig
@@ -10,7 +10,9 @@ pub const std_options: std.Options = .{
 };
 
 fn makeRequest(a: std.mem.Allocator, url: []const u8) !void {
-    var http_client: std.http.Client = .{ .allocator = a };
+    var thread: std.Io.Threaded = .init(a);
+    defer thread.deinit();
+    var http_client: std.http.Client = .{ .allocator = a, .io = thread.io()  };
     defer http_client.deinit();
 
     _ = try http_client.fetch(.{
diff --git a/src/tests/test_recvfile.zig b/src/tests/test_recvfile.zig
index e2da327..875d601 100644
--- a/src/tests/test_recvfile.zig
+++ b/src/tests/test_recvfile.zig
@@ -19,7 +19,9 @@ const EXPECTED_FILENAME = "myfile.txt";
 var test_error: ?anyerror = null;
 
 fn makeRequest(allocator: std.mem.Allocator, url: []const u8) !void {
-    var http_client: std.http.Client = .{ .allocator = allocator };
+    var thread: std.Io.Threaded = .init(allocator);
+    defer thread.deinit();
+    var http_client: std.http.Client = .{ .allocator = allocator, .io = thread.io() };
     defer http_client.deinit();
 
     const payload_wrong_line_ending = try std.fmt.allocPrint(allocator,
diff --git a/src/tests/test_recvfile_notype.zig b/src/tests/test_recvfile_notype.zig
index aa4162c..9f0ab72 100644
--- a/src/tests/test_recvfile_notype.zig
+++ b/src/tests/test_recvfile_notype.zig
@@ -18,7 +18,9 @@ const EXPECTED_FILENAME = "myfile.txt";
 var test_error: ?anyerror = null;
 
 fn makeRequest(allocator: std.mem.Allocator, url: []const u8) !void {
-    var http_client: std.http.Client = .{ .allocator = allocator };
+    var thread: std.Io.Threaded = .init(allocator);
+    defer thread.deinit();
+    var http_client: std.http.Client = .{ .allocator = allocator, .io = thread.io() };
     defer http_client.deinit();
 
     const payload_wrong_line_ending = try std.fmt.allocPrint(allocator,
diff --git a/src/tests/test_sendfile.zig b/src/tests/test_sendfile.zig
index f13cbdd..5b6bfc7 100644
--- a/src/tests/test_sendfile.zig
+++ b/src/tests/test_sendfile.zig
@@ -15,10 +15,12 @@ var read_len: ?usize = null;
 const testfile = @embedFile("testfile.txt");
 
 fn makeRequest(a: std.mem.Allocator, url: []const u8) !void {
-    var http_client: std.http.Client = .{ .allocator = a };
+    var thread: std.Io.Threaded = .init(a);
+    defer thread.deinit();
+    var http_client: std.http.Client = .{ .allocator = a, .io = thread.io()  };
     defer http_client.deinit();
 
-    var response_writer = std.io.Writer.Allocating.init(a);
+    var response_writer = std.Io.Writer.Allocating.init(a);
     defer response_writer.deinit();
 
     _ = try http_client.fetch(.{
diff --git a/src/util.zig b/src/util.zig
index 27e86d8..3c82a6d 100644
--- a/src/util.zig
+++ b/src/util.zig
@@ -77,7 +77,7 @@ pub fn stringifyBuf(
     value: anytype,
     options: std.json.Stringify.Options,
 ) ![]const u8 {
-    var w: std.io.Writer = .fixed(buffer);
+    var w: std.Io.Writer = .fixed(buffer);
     if (std.json.Stringify.value(value, options, &w)) {
         return w.buffered();
     } else |err| { // error
diff --git a/src/zap.zig b/src/zap.zig
index 4e20ddd..984d629 100644
--- a/src/zap.zig
+++ b/src/zap.zig
@@ -288,7 +288,7 @@ pub const HttpListener = struct {
         // in debug2 and debug3 of hello example
         // std.debug.print("X\n", .{});
         // TODO: still happening?
-        std.Thread.sleep(500 * std.time.ns_per_ms);
+        std.posix.nanosleep(0, 500 * std.time.ns_per_ms);
 
         var portbuf: [100]u8 = undefined;
         const printed_port = try std.fmt.bufPrintZ(&portbuf, "{d}", .{self.settings.port});
diff --git a/tools/announceybot.zig b/tools/announceybot.zig
index 9fa8b96..4c331b9 100644
--- a/tools/announceybot.zig
+++ b/tools/announceybot.zig
@@ -144,7 +144,7 @@ fn sendToDiscord(allocator: std.mem.Allocator, url: []const u8, message: []const
     // max size: 100kB
     const buf: []u8 = try allocator.alloc(u8, 100 * 1024);
     defer allocator.free(buf);
-    var w: std.io.Writer = .fixed(buf);
+    var w: std.Io.Writer = .fixed(buf);
     try std.json.Stringify.value(.{ .content = message }, .{}, &w);
     const string = w.buffered();
 
@@ -263,7 +263,7 @@ fn sendToDiscord(allocator: std.mem.Allocator, url: []const u8, message: []const
         const desc = chunks.items[it];
         const part = message[desc.from..desc.to];
 
-        var ww: std.io.Writer = .fixed(buf);
+        var ww: std.Io.Writer = .fixed(buf);
         try std.json.Stringify.value(.{ .content = part }, .{}, &ww);
         const part_string = ww.buffered();