diff --git a/NAMESPACE b/NAMESPACE
index eede0b96e..2883ad092 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -91,6 +91,7 @@ export(request)
 export(send)
 export(send_aio)
 export(serial_config)
+export(server)
 export(set_promise_context)
 export(socket)
 export(stat)
diff --git a/NEWS.md b/NEWS.md
index f30e823aa..51cefe82c 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -4,6 +4,7 @@
 
 * Adds support for threaded dispatcher in `mirai`.
 * Adds 'recvAio' method for `promises::as.promise()` and `promises::is.promising()` to enable 'recvAio' promises.
+* Adds `server()`, an HTTP REST server for evaluation of R expressions (experimental).
 
 #### Updates
 
diff --git a/R/server.R b/R/server.R
new file mode 100644
index 000000000..131aead96
--- /dev/null
+++ b/R/server.R
@@ -0,0 +1,79 @@
+# Copyright (C) 2022-2024 Hibiki AI Limited <info@hibiki-ai.com>
+#
+# This file is part of nanonext.
+#
+# nanonext is free software: you can redistribute it and/or modify it under the
+# terms of the GNU General Public License as published by the Free Software
+# Foundation, either version 3 of the License, or (at your option) any later
+# version.
+#
+# nanonext is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# nanonext. If not, see <https://www.gnu.org/licenses/>.
+
+# nanonext - server - HTTP REST Server -----------------------------------------
+
+#' Start REST Server
+#'
+#' Creates an instance of an HTTP REST server which evaluates R expressions sent
+#'     to it [EXPERIMENTAL]. As arbitrary R expressions are evaluated, this
+#'     should only be deployed on the local machine (using the 127.0.0.1
+#'     loopback address) in a trusted environment.
+#'
+#' @param url full http address including hostname, port and path at which to
+#'     host the server.
+#'
+#' @details Query the API with an HTTP client using the \sQuote{POST} method,
+#'     with the request data being the R expression as a text string. The
+#'     received response body will consist of the evaluation result as a text
+#'     string (if of the appropriate type), or otherwise a serialized R object,
+#'     which should be passed to \code{\link{unserialize}}.
+#'
+#'     If the expression could not be parsed or evaluated, the response will be
+#'     returned with a status code of 500 and a blank body.
+#'
+#'     User interrupts will only be processed after the next query has been
+#'     completed, hence return from the function may not be immediate. Use
+#'     \sQuote{ctrl + \\} to forcibly quit the entire R session if required.
+#'
+#' @return This function never returns.
+#'
+#' @examples
+#' if (interactive()) {
+#'
+#' # run server in a new session:
+#' # Rscript -e 'nanonext::server("http://127.0.0.1:5555/api/rest")'
+#'
+#' # query using curl:
+#' # curl -X POST http://127.0.0.1:5555/api/rest -d 'format(Sys.time())'
+#'
+#' ncurl(
+#'   "http://127.0.0.1:5555/api/rest",
+#'   method = "POST",
+#'   data = "format(Sys.time())"
+#' )
+#'
+#' # error will return status of 500
+#' ncurl(
+#'   "http://127.0.0.1:5555/api/rest",
+#'   method = "POST",
+#'   data = "not_valid()"
+#' )
+#'
+#' res <- ncurl(
+#'   "http://127.0.0.1:5555/api/rest",
+#'   convert = FALSE,
+#'   method = "POST",
+#'   data = "data.frame(random = nanonext::random(3))"
+#' )
+#' if (!is_error_value(res$data)) unserialize(res$data)
+#'
+#' }
+#'
+#' @export
+#'
+server <- function(url = "http://127.0.0.1:5555/api/rest")
+  .Call(rnng_rest_server, url)
diff --git a/man/server.Rd b/man/server.Rd
new file mode 100644
index 000000000..c724480b5
--- /dev/null
+++ b/man/server.Rd
@@ -0,0 +1,68 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/server.R
+\name{server}
+\alias{server}
+\title{Start REST Server}
+\usage{
+server(url = "http://127.0.0.1:5555/api/rest")
+}
+\arguments{
+\item{url}{full http address including hostname, port and path at which to
+host the server.}
+}
+\value{
+This function never returns.
+}
+\description{
+Creates an instance of an HTTP REST server which evaluates R expressions sent
+    to it [EXPERIMENTAL]. As arbitrary R expressions are evaluated, this
+    should only be deployed on the local machine (using the 127.0.0.1
+    loopback address) in a trusted environment.
+}
+\details{
+Query the API with an HTTP client using the \sQuote{POST} method,
+    with the request data being the R expression as a text string. The
+    received response body will consist of the evaluation result as a text
+    string (if of the appropriate type), or otherwise a serialized R object,
+    which should be passed to \code{\link{unserialize}}.
+
+    If the expression could not be parsed or evaluated, the response will be
+    returned with a status code of 500 and a blank body.
+
+    User interrupts will only be processed after the next query has been
+    completed, hence return from the function may not be immediate. Use
+    \sQuote{ctrl + \\} to forcibly quit the entire R session if required.
+}
+\examples{
+if (interactive()) {
+
+# run server in a new session:
+# Rscript -e 'nanonext::server("http://127.0.0.1:5555/api/rest")'
+
+# query using curl:
+# curl -X POST http://127.0.0.1:5555/api/rest -d 'format(Sys.time())'
+
+ncurl(
+  "http://127.0.0.1:5555/api/rest",
+  method = "POST",
+  data = "format(Sys.time())"
+)
+
+# error will return status of 500
+ncurl(
+  "http://127.0.0.1:5555/api/rest",
+  method = "POST",
+  data = "not_valid()"
+)
+
+res <- ncurl(
+  "http://127.0.0.1:5555/api/rest",
+  convert = FALSE,
+  method = "POST",
+  data = "data.frame(random = nanonext::random(3))"
+)
+if (!is_error_value(res$data)) unserialize(res$data)
+
+}
+
+}
diff --git a/src/init.c b/src/init.c
index f03fb3339..d9a83cc17 100644
--- a/src/init.c
+++ b/src/init.c
@@ -167,6 +167,7 @@ static const R_CallMethodDef callMethods[] = {
   {"rnng_recv", (DL_FUNC) &rnng_recv, 4},
   {"rnng_recv_aio", (DL_FUNC) &rnng_recv_aio, 6},
   {"rnng_request", (DL_FUNC) &rnng_request, 7},
+  {"rnng_rest_server", (DL_FUNC) &rnng_rest_server, 1},
   {"rnng_send", (DL_FUNC) &rnng_send, 4},
   {"rnng_send_aio", (DL_FUNC) &rnng_send_aio, 5},
   {"rnng_serial_config", (DL_FUNC) &rnng_serial_config, 4},
diff --git a/src/nanonext.h b/src/nanonext.h
index 8acf5791e..ac9b577bc 100644
--- a/src/nanonext.h
+++ b/src/nanonext.h
@@ -294,6 +294,7 @@ int nano_matchargs(const SEXP);
 
 void pipe_cb_signal(nng_pipe, nng_pipe_ev, void *);
 void tls_finalizer(SEXP);
+void nano_printf(const int, const char *, ...);
 
 SEXP rnng_advance_rng_state(void);
 SEXP rnng_aio_call(SEXP);
@@ -347,6 +348,7 @@ SEXP rnng_reap(SEXP);
 SEXP rnng_recv(SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_recv_aio(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_request(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
+SEXP rnng_rest_server(SEXP);
 SEXP rnng_send(SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_send_aio(SEXP, SEXP, SEXP, SEXP, SEXP);
 SEXP rnng_serial_config(SEXP, SEXP, SEXP, SEXP);
diff --git a/src/server.c b/src/server.c
new file mode 100644
index 000000000..2d793c7f8
--- /dev/null
+++ b/src/server.c
@@ -0,0 +1,289 @@
+// Copyright (C) 2022-2024 Hibiki AI Limited <info@hibiki-ai.com>
+//
+// This file is part of nanonext.
+//
+// nanonext is free software: you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the Free Software
+// Foundation, either version 3 of the License, or (at your option) any later
+// version.
+//
+// nanonext is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+// A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// nanonext. If not, see <https://www.gnu.org/licenses/>.
+
+// nanonext - HTTP REST Sever --------------------------------------------------
+
+#define NANONEXT_HTTP
+#define NANONEXT_PROTOCOLS
+#include "nanonext.h"
+
+// REST server -----------------------------------------------------------------
+
+// This file contains modified code with the following licence:
+//
+// Copyright 2018 Staysail Systems, Inc. <info@staysail.tech>
+// Copyright 2018 Capitar IT Group BV <info@capitar.com>
+//
+// This software is supplied under the terms of the MIT License, a
+// copy of which should be located in the distribution where this
+// file was obtained (LICENSE.txt).  A copy of the license may also be
+// found online at https://opensource.org/licenses/MIT.
+//
+
+typedef enum {
+  SEND_REQ,
+  RECV_REP,
+} job_state;
+
+typedef struct rest_job {
+  nng_aio *        http_aio; // aio from HTTP we must reply to
+  nng_http_res *   http_res; // HTTP response object
+  job_state        state;    // 0 = sending, 1 = receiving
+  nng_msg *        msg;      // request message
+  nng_aio *        aio;      // request flow
+  nng_ctx          ctx;      // context on the request socket
+  struct rest_job *next;     // next on the freelist
+} rest_job;
+
+nng_mtx * job_lock;
+rest_job *job_freelist;
+nng_socket req_sock;
+
+static void fatal(const char *reason, int xc) {
+  nano_printf(1, "%s: %s\n", reason, nng_strerror(xc));
+}
+
+static void rest_recycle_job(rest_job *job) {
+
+  if (job->http_res != NULL) {
+    nng_http_res_free(job->http_res);
+    job->http_res = NULL;
+  }
+  if (job->msg != NULL) {
+    nng_msg_free(job->msg);
+    job->msg = NULL;
+  }
+  if (nng_ctx_id(job->ctx) != 0) {
+    nng_ctx_close(job->ctx);
+  }
+
+  nng_mtx_lock(job_lock);
+  job->next = job_freelist;
+  job_freelist = job;
+  nng_mtx_unlock(job_lock);
+
+}
+
+static void rest_http_fatal(rest_job *job, const char *fmt, int rv) {
+
+  char buf[128];
+  nng_aio *aio = job->http_aio;
+  nng_http_res *res = job->http_res;
+
+  job->http_res = NULL;
+  job->http_aio = NULL;
+  snprintf(buf, sizeof(buf), fmt, nng_strerror(rv));
+  nng_http_res_set_status(res, NNG_HTTP_STATUS_INTERNAL_SERVER_ERROR);
+  nng_http_res_set_reason(res, buf);
+  nng_aio_set_output(aio, 0, res);
+  nng_aio_finish(aio, 0);
+  rest_recycle_job(job);
+
+}
+
+static void rest_job_cb(void *arg) {
+
+  rest_job *job = arg;
+  nng_aio *aio = job->aio;
+  int xc;
+
+  switch (job->state) {
+  case SEND_REQ:
+    if ((xc = nng_aio_result(aio))) {
+      rest_http_fatal(job, "send REQ failed: %s", xc);
+      return;
+    }
+    job->msg = NULL;
+    nng_aio_set_msg(aio, NULL);
+    job->state = RECV_REP;
+    nng_ctx_recv(job->ctx, aio);
+    break;
+  case RECV_REP:
+    if ((xc = nng_aio_result(aio))) {
+      rest_http_fatal(job, "recv reply failed: %s", xc);
+      return;
+    }
+    job->msg = nng_aio_get_msg(aio);
+    if ((xc = nng_http_res_copy_data(job->http_res,
+                                     nng_msg_body(job->msg),
+                                     nng_msg_len(job->msg)))) {
+      rest_http_fatal(job, "nng_http_res_copy_data: %s", xc);
+      return;
+    }
+    nng_aio_set_output(job->http_aio, 0, job->http_res);
+    nng_aio_finish(job->http_aio, 0);
+    job->http_aio = NULL;
+    job->http_res = NULL;
+    rest_recycle_job(job);
+    break;
+  default:
+    fatal("bad case", NNG_ESTATE);
+    break;
+  }
+
+}
+
+static rest_job *rest_get_job(void) {
+
+  rest_job *job;
+
+  nng_mtx_lock(job_lock);
+  if ((job = job_freelist) != NULL) {
+    job_freelist = job->next;
+    nng_mtx_unlock(job_lock);
+    job->next = NULL;
+    return (job);
+  }
+  nng_mtx_unlock(job_lock);
+  if ((job = calloc(1, sizeof(*job))) == NULL) {
+    return (NULL);
+  }
+  if (nng_aio_alloc(&job->aio, rest_job_cb, job) != 0) {
+    free(job);
+    return (NULL);
+  }
+  return (job);
+
+}
+
+void rest_handle(nng_aio *aio) {
+
+  struct rest_job *job;
+  nng_http_req *req = nng_aio_get_input(aio, 0);
+  void *data;
+  size_t sz;
+  int xc;
+
+  if ((job = rest_get_job()) == NULL) {
+    nng_aio_finish(aio, NNG_ENOMEM);
+    return;
+  }
+  if ((xc = nng_http_res_alloc(&job->http_res)) ||
+      (xc = nng_ctx_open(&job->ctx, req_sock))) {
+    rest_recycle_job(job);
+    nng_aio_finish(aio, xc);
+    return;
+  }
+
+  nng_http_req_get_data(req, &data, &sz);
+  job->http_aio = aio;
+
+  if ((xc = nng_msg_alloc(&job->msg, sz))) {
+    rest_http_fatal(job, "nng_msg_alloc: %s", xc);
+    return;
+  }
+
+  memcpy(nng_msg_body(job->msg), data, sz);
+  nng_aio_set_msg(job->aio, job->msg);
+  job->state = SEND_REQ;
+  nng_ctx_send(job->ctx, job->aio);
+
+}
+
+void rest_start(void *arg) {
+
+  const char **addr = (const char **) arg;
+  nng_http_server *server;
+  nng_http_handler *handler;
+  nng_url *url;
+  int xc;
+
+  if ((xc = nng_mtx_alloc(&job_lock)))
+    fatal("nng_mtx_alloc", xc);
+
+  job_freelist = NULL;
+
+  if ((xc = nng_url_parse(&url, addr[0])))
+    fatal("nng_url_parse", xc);
+
+  if ((xc = nng_req0_open(&req_sock)))
+    fatal("nng_req0_open", xc);
+
+  if ((xc = nng_dial(req_sock, addr[1], NULL, NNG_FLAG_NONBLOCK)))
+    fatal("nng_dial(inproc_url)", xc);
+
+  if ((xc = nng_http_server_hold(&server, url)))
+    fatal("nng_http_server_hold", xc);
+
+  if ((xc = nng_http_handler_alloc(&handler, url->u_path, rest_handle)))
+    fatal("nng_http_handler_alloc", xc);
+
+  if ((xc = nng_http_handler_set_method(handler, "POST")))
+    fatal("nng_http_handler_set_method", xc);
+
+  if ((xc = nng_http_handler_collect_body(handler, true, 1024 * 128)))
+    fatal("nng_http_handler_collect_body", xc);
+
+  if ((xc = nng_http_server_add_handler(server, handler)))
+    fatal("nng_http_handler_add_handler", xc);
+
+  if ((xc = nng_http_server_start(server)))
+    fatal("nng_http_server_start", xc);
+
+  nng_url_free(url);
+
+}
+
+static SEXP nano_parse_eval_res;
+
+void parse_eval_safe(void *data) {
+  nano_parse_eval_res = R_ParseEvalString((const char *) data, R_GlobalEnv);
+}
+
+SEXP rnng_rest_server(SEXP url) {
+
+  const char *addr[2] = {CHAR(STRING_ELT(url, 0)), "inproc://n-a-n-o-serv"};
+  nng_thread *thr;
+  nng_socket s;
+  nng_msg *msg;
+  int xc;
+
+  if ((xc = nng_thread_create(&thr, rest_start, (void *) addr)))
+    ERROR_OUT(xc);
+
+  if ((xc = nng_rep0_open(&s)) ||
+      (xc = nng_listen(s, addr[1], NULL, 0)))
+    fatal("unable to set up inproc", xc);
+
+  for (;;) {
+
+    if ((xc = nng_recvmsg(s, &msg, 0)))
+      fatal("inproc recvmsg", xc);
+
+    nano_parse_eval_res = R_BlankScalarString;
+    R_ToplevelExec(parse_eval_safe, (void *) nng_msg_body(msg));
+
+    nano_buf buf;
+    if (TYPEOF(nano_parse_eval_res) == STRSXP) {
+      const char *string = NANO_STRING(nano_parse_eval_res);
+      buf.buf = (unsigned char *) string;
+      buf.cur = strlen(string);
+    } else {
+      nano_serialize(&buf, nano_parse_eval_res, R_NilValue);
+    }
+    nng_msg_clear(msg);
+    nng_msg_append(msg, buf.buf, buf.cur);
+    if ((xc = nng_sendmsg(s, msg, 0)))
+      fatal("inproc sendmsg", xc);
+
+    R_CheckUserInterrupt();
+
+  }
+
+  nng_thread_destroy(thr);
+  return R_NilValue;
+
+}
diff --git a/src/thread.c b/src/thread.c
index fbde57ba3..98e8323a3 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -25,7 +25,8 @@
 // # nocov start
 // tested interactively
 
-static void nano_printf(const int err, const char *fmt, ...) {
+void nano_printf(const int err, const char *fmt, ...) {
+
 
   char buf[NANONEXT_INIT_BUFSIZE];
   va_list arg_ptr;