diff --git a/.github/build.sh b/.github/build.sh
index 5f3105a23..3f8f2ec90 100755
--- a/.github/build.sh
+++ b/.github/build.sh
@@ -297,7 +297,6 @@ if [[ $BSH_HOST_PLATFORM-$BSH_HOST_ARCH == darwin-aarch64 ]]; then
 	meson_configure+=$'\t'--cross-file=.github/macaa64-ghactions.ini
 fi
 if [[ $BSH_HOST_PLATFORM == emscripten ]]; then
-	meson_configure+=$'\t'-Dhttp=false # TODO: fix
 	meson_configure+=$'\t'--cross-file=.github/emscripten-ghactions.ini
 fi
 if [[ $RELEASE_TYPE == tptlibsdev ]] && ([[ $BSH_HOST_PLATFORM == windows ]] || [[ $BSH_STATIC_DYNAMIC == static ]]); then
diff --git a/src/Config.template.h b/src/Config.template.h
index 684e36061..df259cc38 100644
--- a/src/Config.template.h
+++ b/src/Config.template.h
@@ -47,3 +47,6 @@ constexpr char STATICSCHEME[]   = "https://";
 constexpr char LOCAL_SAVE_DIR[] = "Saves";
 constexpr char STAMPS_DIR[]     = "stamps";
 constexpr char BRUSH_DIR[]      = "Brushes";
+
+constexpr int httpMaxConcurrentStreams = 50;
+constexpr int httpConnectTimeoutS      = 15;
diff --git a/src/client/http/requestmanager/Emscripten.cpp b/src/client/http/requestmanager/Emscripten.cpp
new file mode 100644
index 000000000..1ef7d8ead
--- /dev/null
+++ b/src/client/http/requestmanager/Emscripten.cpp
@@ -0,0 +1,376 @@
+#include "RequestManager.h"
+#include "client/http/Request.h"
+#include <algorithm>
+#include <emscripten.h>
+#include <emscripten/threading.h>
+
+namespace http
+{
+	struct RequestHandleHttp : public RequestHandle
+	{
+		RequestHandleHttp() : RequestHandle(CtorTag{})
+		{
+		}
+
+		bool gotResponse = false;
+		int id = -1;
+	};
+}
+
+extern "C" void RequestManager_UpdateRequestStatusThunk(http::RequestHandleHttp *handle);
+
+namespace http
+{
+	std::shared_ptr<RequestHandle> RequestHandle::Create()
+	{
+		return std::make_shared<RequestHandleHttp>();
+	}
+
+	struct RequestManagerImpl : public RequestManager
+	{
+		using RequestManager::RequestManager;
+
+		RequestManagerImpl(ByteString newProxy, ByteString newCafile, ByteString newCapath, bool newDisableNetwork);
+		~RequestManagerImpl();
+
+		// State shared between Request threads and the worker thread.
+		std::vector<std::shared_ptr<RequestHandle>> requestHandlesToRegister;
+		std::vector<std::shared_ptr<RequestHandle>> requestHandlesToUnregister;
+		std::mutex sharedStateMx;
+
+		std::vector<std::shared_ptr<RequestHandle>> requestHandles;
+		void RegisterRequestHandle(std::shared_ptr<RequestHandle> requestHandle);
+		void UnregisterRequestHandle(std::shared_ptr<RequestHandle> requestHandle);
+
+		void HandleWake();
+		void Wake();
+
+		void UpdateRequestStatus(RequestHandleHttp *handle);
+	};
+
+	RequestManagerImpl::RequestManagerImpl(ByteString newProxy, ByteString newCafile, ByteString newCapath, bool newDisableNetwork) :
+		RequestManager(newProxy, newCafile, newCapath, newDisableNetwork)
+	{
+		EM_ASM({
+			Module.emscriptenRequestManager = {};
+			Module.emscriptenRequestManager.requests = [];
+			Module.emscriptenRequestManager.updateRequestStatus = Module.cwrap(
+				'RequestManager_UpdateRequestStatusThunk',
+				null,
+				[ 'number' ]
+			);
+		});
+	}
+
+	RequestManagerImpl::~RequestManagerImpl()
+	{
+		// Nothing, we never really exit.
+	}
+
+	void RequestManager::RegisterRequestImpl(Request &request)
+	{
+		auto manager = static_cast<RequestManagerImpl *>(this);
+		{
+			std::lock_guard lk(manager->sharedStateMx);
+			manager->requestHandlesToRegister.push_back(request.handle);
+		}
+		manager->Wake();
+	}
+
+	void RequestManager::UnregisterRequestImpl(Request &request)
+	{
+		auto manager = static_cast<RequestManagerImpl *>(this);
+		{
+			std::lock_guard lk(manager->sharedStateMx);
+			manager->requestHandlesToUnregister.push_back(request.handle);
+		}
+		manager->Wake();
+	}
+
+	void RequestManagerImpl::HandleWake()
+	{
+		{
+			std::lock_guard lk(sharedStateMx);
+			for (auto &requestHandle : requestHandles)
+			{
+				if (requestHandle->statusCode)
+				{
+					requestHandlesToUnregister.push_back(requestHandle);
+				}
+			}
+			for (auto &requestHandle : requestHandlesToRegister)
+			{
+				// Must not be present
+				assert(std::find(requestHandles.begin(), requestHandles.end(), requestHandle) == requestHandles.end());
+				requestHandles.push_back(requestHandle);
+				RegisterRequestHandle(requestHandle);
+			}
+			requestHandlesToRegister.clear();
+			for (auto &requestHandle : requestHandlesToUnregister)
+			{
+				auto eraseFrom = std::remove(requestHandles.begin(), requestHandles.end(), requestHandle);
+				// Must either not be present
+				if (eraseFrom != requestHandles.end())
+				{
+					// Or be present exactly once
+					assert(eraseFrom + 1 == requestHandles.end());
+					UnregisterRequestHandle(requestHandle);
+					requestHandles.erase(eraseFrom, requestHandles.end());
+					requestHandle->MarkDone();
+				}
+			}
+			requestHandlesToUnregister.clear();
+		}
+	}
+
+	static void HandleWakeThunk()
+	{
+		auto manager = static_cast<RequestManagerImpl *>(&RequestManager::Ref());
+		manager->HandleWake();
+	}
+
+	void RequestManagerImpl::Wake()
+	{
+		emscripten_async_run_in_main_runtime_thread(EM_FUNC_SIG_V, &HandleWakeThunk);
+	}
+
+	void RequestManagerImpl::RegisterRequestHandle(std::shared_ptr<RequestHandle> requestHandle)
+	{
+		auto handle = static_cast<RequestHandleHttp *>(requestHandle.get());
+		handle->id = EM_ASM_INT({
+			let id = 0;
+			while (Module.emscriptenRequestManager.requests[id])
+			{
+				id += 1;
+			}
+			let request = {};
+			request.fetchResource = UTF8ToString($0);
+			request.fetchBody = undefined;
+			request.fetchHeaders = new Headers(); 
+			Module.emscriptenRequestManager.requests[id] = request;
+			return id;
+		}, requestHandle->uri.c_str());
+		if (handle->headers.size())
+		{
+			for (auto &header : handle->headers)
+			{
+				EM_ASM({
+					Module.emscriptenRequestManager.requests[$0].fetchHeaders.append(
+						UTF8ToString($1),
+						UTF8ToString($2)
+					);
+				}, handle->id, header.name.c_str(), header.value.c_str());
+			}
+		}
+		auto &postData = handle->postData;
+		if (std::holds_alternative<http::FormData>(postData) && std::get<http::FormData>(postData).size())
+		{
+			auto &formData = std::get<http::FormData>(postData);
+			EM_ASM({
+				Module.emscriptenRequestManager.requests[$0].fetchBody = new FormData();
+			}, handle->id);
+			for (auto &field : formData)
+			{
+				if (field.filename.has_value())
+				{
+					EM_ASM({
+						Module.emscriptenRequestManager.requests[$0].fetchBody.append(
+							UTF8ToString($1),
+							new Blob([ HEAP8.slice($2, $2 + $3) ]),
+							UTF8ToString($4)
+						);
+					}, handle->id, field.name.c_str(), &field.value[0], field.value.size(), field.filename->c_str());
+				}
+				else
+				{
+					EM_ASM({
+						Module.emscriptenRequestManager.requests[$0].fetchBody.append(
+							UTF8ToString($1),
+							UTF8ToString($2)
+						)
+					}, handle->id, field.name.c_str(), field.value.c_str());
+				}
+			}
+		}
+		else if (std::holds_alternative<http::StringData>(postData) && std::get<http::StringData>(postData).size())
+		{
+			auto &stringData = std::get<http::StringData>(postData);
+			EM_ASM({
+				Module.emscriptenRequestManager.requests[$0].fetchBody = new DataView(
+					HEAP8.buffer,
+					HEAP8.byteOffset + $1,
+					$2
+				);
+			}, handle->id, &stringData[0], stringData.size());
+		}
+		if (handle->isPost)
+		{
+			EM_ASM({
+				Module.emscriptenRequestManager.requests[$0].fetchMethod = 'POST';
+			}, handle->id);
+		}
+		else
+		{
+			EM_ASM({
+				Module.emscriptenRequestManager.requests[$0].fetchMethod = 'GET';
+			}, handle->id);
+		}
+		if (requestHandle->verb)
+		{
+			EM_ASM({
+				Module.emscriptenRequestManager.requests[$0].fetchMethod = UTF8ToString($1);
+			}, handle->id, requestHandle->verb->c_str());
+		}
+		// TODO: set max redirects
+		// TODO: set max concurrent streams
+		// TODO: set connect timeout
+		EM_ASM({
+			let request = Module.emscriptenRequestManager.requests[$0];
+			let token = $1;
+			request.status = 0;
+			request.bytesTotal = -1;
+			request.bytesDone = 0;
+			Module.emscriptenRequestManager.updateRequestStatus(token);
+			request.fetchController = new AbortController();
+			fetch(request.fetchResource, {
+				method: request.fetchMethod,
+				headers: request.fetchHeaders,
+				body: request.fetchBody,
+				credentials: 'omit',
+				signal: request.fetchController.signal,
+			}).then(response => {
+				request.statusEarly = response.status;
+				let contentLength = response.headers.get('content-length');
+				if (contentLength) {
+					request.bytesTotal = parseInt(contentLength, 10);
+				}
+				let reader = response.body.getReader();
+				let stream = new ReadableStream({
+					start(controller) {
+						function read() {
+							reader.read().then(({ done, value }) => {
+								if (done) {
+									return controller.close();
+								}
+								request.bytesDone += value.byteLength;
+								Module.emscriptenRequestManager.updateRequestStatus(token);
+								controller.enqueue(value);
+								read();
+							}).catch(err => {
+								controller.error(err);
+							});
+						}
+						read();
+					}
+				});
+				request.responseHeaders = [];
+				for (let [ name, value ] of response.headers.entries()) {
+					request.responseHeaders.push({
+						name: name,
+						value: value
+					});
+				}
+				return new Response(stream, {
+					headers: response.headers
+				});
+			}).then(output => {
+				return output.arrayBuffer();
+			}).then(data => {
+				request.status = request.statusEarly;
+				request.responseData = data;
+				Module.emscriptenRequestManager.updateRequestStatus(token);
+			}).catch(err => {
+				console.error(err);
+				if (!request.status) {
+					request.status = 600;
+				}
+				Module.emscriptenRequestManager.updateRequestStatus(token);
+			});
+		}, handle->id, handle);
+	}
+
+	void RequestManagerImpl::UpdateRequestStatus(RequestHandleHttp *handle)
+	{
+		assert(handle->id >= 0);
+		handle->bytesTotal = EM_ASM_INT({
+			return Module.emscriptenRequestManager.requests[$0].bytesTotal;
+		}, handle->id);
+		handle->bytesDone = EM_ASM_INT({
+			return Module.emscriptenRequestManager.requests[$0].bytesDone;
+		}, handle->id);
+		handle->statusCode = EM_ASM_INT({
+			return Module.emscriptenRequestManager.requests[$0].status;
+		}, handle->id);
+		if (!handle->gotResponse && handle->statusCode)
+		{
+			auto responseDataSize = EM_ASM_INT({
+				let responseData = Module.emscriptenRequestManager.requests[$0].responseData;
+				if (responseData) {
+					return responseData.byteLength;
+				}
+				return 0;
+			}, handle->id);
+			if (responseDataSize)
+			{
+				handle->responseData.resize(responseDataSize);
+				EM_ASM({
+					let responseData = Module.emscriptenRequestManager.requests[$0].responseData;
+					writeArrayToMemory(new Int8Array(responseData), $1);
+				}, handle->id, &handle->responseData[0]);
+			}
+			auto headerCount = EM_ASM_INT({
+				let responseHeaders = Module.emscriptenRequestManager.requests[$0].responseHeaders;
+				if (responseHeaders) {
+					return responseHeaders.length;
+				}
+				return 0;
+			}, handle->id);
+			handle->responseHeaders.resize(headerCount);
+			for (auto i = 0; i < headerCount; ++i)
+			{
+				handle->responseHeaders[i].name.resize(EM_ASM_INT({
+					return lengthBytesUTF8(Module.emscriptenRequestManager.requests[$0].responseHeaders[$1].name);
+				}, handle->id, i));
+				EM_ASM({
+					stringToUTF8(Module.emscriptenRequestManager.requests[$0].responseHeaders[$1].name, $2, $3);
+				}, handle->id, i, &handle->responseHeaders[i].name[0], handle->responseHeaders[i].name.size());
+				handle->responseHeaders[i].value.resize(EM_ASM_INT({
+					return lengthBytesUTF8(Module.emscriptenRequestManager.requests[$0].responseHeaders[$1].value);
+				}, handle->id, i));
+				EM_ASM({
+					stringToUTF8(Module.emscriptenRequestManager.requests[$0].responseHeaders[$1].value, $2, $3);
+				}, handle->id, i, &handle->responseHeaders[i].value[0], handle->responseHeaders[i].value.size());
+			}
+			handle->gotResponse = true;
+			HandleWake();
+		}
+	}
+
+	void RequestManagerImpl::UnregisterRequestHandle(std::shared_ptr<RequestHandle> requestHandle)
+	{
+		auto handle = static_cast<RequestHandleHttp *>(requestHandle.get());
+		assert(handle->id >= 0);
+		EM_ASM({
+			let request = Module.emscriptenRequestManager.requests[$0];
+			request.fetchController.abort();
+			Module.emscriptenRequestManager.requests[$0] = null;
+		}, handle->id);
+		handle->id = -1;
+	}
+
+	RequestManagerPtr RequestManager::Create(ByteString newProxy, ByteString newCafile, ByteString newCapath, bool newDisableNetwork)
+	{
+		return RequestManagerPtr(new RequestManagerImpl(newProxy, newCafile, newCapath, newDisableNetwork));
+	}
+
+	void RequestManagerDeleter::operator ()(RequestManager *ptr) const
+	{
+		delete static_cast<RequestManagerImpl *>(ptr);
+	}
+}
+
+void RequestManager_UpdateRequestStatusThunk(http::RequestHandleHttp *handle)
+{
+	auto manager = static_cast<http::RequestManagerImpl *>(&http::RequestManager::Ref());
+	manager->UpdateRequestStatus(handle);
+}
diff --git a/src/client/http/requestmanager/Libcurl.cpp b/src/client/http/requestmanager/Libcurl.cpp
index 274924c4f..64dc244e5 100644
--- a/src/client/http/requestmanager/Libcurl.cpp
+++ b/src/client/http/requestmanager/Libcurl.cpp
@@ -15,9 +15,9 @@
 # define REQUEST_USE_CURL_TLSV13CL
 #endif
 
-const long curlMaxHostConnections   = 1;
-const long curlMaxConcurrentStreams = 50;
-const long curlConnectTimeoutS      = 15;
+constexpr long curlMaxHostConnections   = 1;
+constexpr long curlMaxConcurrentStreams = httpMaxConcurrentStreams;
+constexpr long curlConnectTimeoutS      = httpConnectTimeoutS;
 
 namespace http
 {
@@ -275,6 +275,8 @@ namespace http
 				}
 				for (auto &requestHandle : requestHandlesToRegister)
 				{
+					// Must not be present
+					assert(std::find(requestHandles.begin(), requestHandles.end(), requestHandle) == requestHandles.end());
 					requestHandles.push_back(requestHandle);
 					RegisterRequestHandle(requestHandle);
 				}
@@ -282,8 +284,10 @@ namespace http
 				for (auto &requestHandle : requestHandlesToUnregister)
 				{
 					auto eraseFrom = std::remove(requestHandles.begin(), requestHandles.end(), requestHandle);
+					// Must either not be present
 					if (eraseFrom != requestHandles.end())
 					{
+						// Or be present exactly once
 						assert(eraseFrom + 1 == requestHandles.end());
 						UnregisterRequestHandle(requestHandle);
 						requestHandles.erase(eraseFrom, requestHandles.end());
diff --git a/src/client/http/requestmanager/meson.build b/src/client/http/requestmanager/meson.build
index 8ee8603e7..3fd3287c7 100644
--- a/src/client/http/requestmanager/meson.build
+++ b/src/client/http/requestmanager/meson.build
@@ -2,9 +2,15 @@ client_files += files(
 	'Common.cpp',
 )
 
-if enable_http
-	client_files += files('Libcurl.cpp')
-else
+if not enable_http
 	client_files += files('Null.cpp')
+elif host_platform == 'emscripten'
+	client_files += files('Emscripten.cpp')
+	project_link_args += [
+		'-s', 'EXPORTED_FUNCTIONS=_main,_RequestManager_UpdateRequestStatusThunk',
+		'-s', 'EXPORTED_RUNTIME_METHODS=cwrap',
+	]
+else
+	client_files += files('Libcurl.cpp')
 endif
 conf_data.set('NOHTTP', not enable_http ? 'true' : 'false')
diff --git a/src/lua/meson.build b/src/lua/meson.build
index 1b842cf21..53cac68ff 100644
--- a/src/lua/meson.build
+++ b/src/lua/meson.build
@@ -24,10 +24,10 @@ if host_platform == 'windows'
 else
 	luaconsole_files += files('LuaSocketDefault.cpp')
 endif
-if enable_http
-	luaconsole_files += files('LuaSocketTCPHttp.cpp')
-else
+if not enable_http or host_platform == 'emscripten'
 	luaconsole_files += files('LuaSocketTCPNoHttp.cpp')
+else
+	luaconsole_files += files('LuaSocketTCPHttp.cpp')
 endif
 conf_data.set('LUACONSOLE', lua_variant != 'none' ? 'true' : 'false')