diff --git a/Makefile b/Makefile
index 0800e659..0aad5964 100644
--- a/Makefile
+++ b/Makefile
@@ -12,8 +12,15 @@ ifeq ($m, 64)
 ARCH = -m64
 endif
 
+UNAME_S := $(shell uname -s)
+
+ifeq ($(UNAME_S),FreeBSD)
+CFLAGS = $(ARCH) -O3 -std=gnu11 -Wall -Wno-array-bounds -mpclmul -march=core2 -mfpmath=sse -mssse3 -fno-strict-aliasing -fwrapv -DAES=1 -DCOMMIT=\"${COMMIT}\" -D_GNU_SOURCE=1 -D_FILE_OFFSET_BITS=64 -I/usr/local/include -I/usr/local/include/libepoll-shim
+LDFLAGS = $(ARCH) -ggdb -L/usr/local/lib -lm -lcrypto -lz -lpthread -lepoll-shim -lexecinfo
+else
 CFLAGS = $(ARCH) -O3 -std=gnu11 -Wall -Wno-array-bounds -mpclmul -march=core2 -mfpmath=sse -mssse3 -fno-strict-aliasing -fno-strict-overflow -fwrapv -DAES=1 -DCOMMIT=\"${COMMIT}\" -D_GNU_SOURCE=1 -D_FILE_OFFSET_BITS=64
 LDFLAGS = $(ARCH) -ggdb -rdynamic -lm -lrt -lcrypto -lz -lpthread -lcrypto
+endif
 
 LIB = ${OBJ}/lib
 CINCLUDE = -iquote common -iquote .
diff --git a/common/crc32.c b/common/crc32.c
index a7a77fe5..69c4bd25 100644
--- a/common/crc32.c
+++ b/common/crc32.c
@@ -31,6 +31,19 @@
 #include "common/cpuid.h"
 #include "common/kprintf.h"
 
+/* Compatibility for GCC intrinsics when using clang */
+#ifdef __clang__
+#include <emmintrin.h>
+#include <tmmintrin.h>
+#include <wmmintrin.h>
+
+#define __builtin_ia32_loaddqu(p) ((__m128i)_mm_loadu_si128((const __m128i *)(p)))
+#define __builtin_ia32_pshufb128(a, b) ((__m128i)_mm_shuffle_epi8((__m128i)(a), (__m128i)(b)))
+#define __builtin_ia32_pslldqi128(a, n) _mm_slli_si128((__m128i)(a), (n) / 8)
+#define __builtin_ia32_psrldqi128(a, n) _mm_srli_si128((__m128i)(a), (n) / 8)
+#define __builtin_ia32_punpckhqdq128(a, b) _mm_unpackhi_epi64((__m128i)(a), (__m128i)(b))
+#endif
+
 
 #define FASTMOV_RMI32_TO_SSE(dst, src) \
 	asm volatile ("movd %1, %0\n\t" : "=x" (dst) : "g" (src))
diff --git a/common/mp-queue.c b/common/mp-queue.c
index de69bd45..c6d32bb8 100644
--- a/common/mp-queue.c
+++ b/common/mp-queue.c
@@ -32,8 +32,14 @@
 #include <time.h>
 #include <unistd.h>
 
+#ifdef __linux__
 #include <linux/futex.h>
 #include <sys/syscall.h>
+#endif
+#ifdef __FreeBSD__
+#include <sys/types.h>
+#include <sys/umtx.h>
+#endif
 
 #include "server-functions.h"
 #include "kprintf.h"
@@ -116,12 +122,16 @@ int get_this_thread_id (void) {
   return mpq_this_thread_id = i;
 }
 
-/* custom semaphore implementation using futexes */
+/* custom semaphore implementation using futexes (Linux) or umtx (FreeBSD) */
 
 int mp_sem_post (mp_sem_t *sem) {
   __sync_fetch_and_add (&sem->value, 1);
   if (sem->waiting > 0) {
+#ifdef __linux__
     syscall (__NR_futex, &sem->value, FUTEX_WAKE, 1, NULL, 0, 0);
+#elif defined(__FreeBSD__)
+    _umtx_op (&sem->value, UMTX_OP_WAKE, 1, NULL, NULL);
+#endif
   }
   return 0;
 }
@@ -142,7 +152,11 @@ int mp_sem_wait (mp_sem_t *sem) {
 	continue;
       }
       __sync_fetch_and_add (&sem->waiting, 1);
+#ifdef __linux__
       syscall (__NR_futex, &sem->value, FUTEX_WAIT, v, NULL, 0, 0);
+#elif defined(__FreeBSD__)
+      _umtx_op (&sem->value, UMTX_OP_WAIT_UINT, v, NULL, NULL);
+#endif
       __sync_fetch_and_add (&sem->waiting, -1);
       v = sem->value;
       q = 0;
diff --git a/common/resolver.c b/common/resolver.c
index b88f73ab..f0c4cb81 100644
--- a/common/resolver.c
+++ b/common/resolver.c
@@ -29,6 +29,9 @@
 #include <fcntl.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
 #include <errno.h>
 #include <netdb.h>
 
diff --git a/engine/engine.c b/engine/engine.c
index 8489f038..f8be9ed0 100644
--- a/engine/engine.c
+++ b/engine/engine.c
@@ -310,7 +310,9 @@ void server_init (conn_type_t *listen_connection_type, void *listen_connection_e
   ksignal (SIGINT,  sigint_handler);
   ksignal (SIGTERM, sigterm_handler);
   ksignal (SIGPIPE, empty_signal_handler);
+#ifdef SIGPOLL
   ksignal (SIGPOLL, empty_signal_handler);
+#endif
 
   if (daemonize) {
     ksignal (SIGHUP, default_signal_handler);
@@ -534,11 +536,19 @@ static void check_server_functions (void) /* {{{ */ {
 
   check_signal_handler (F, SIGHUP, default_sighup);
   check_signal_handler (F, SIGUSR1, default_sigusr1);
+#ifndef __FreeBSD__
   check_signal_handler (F, SIGRTMAX-9, default_sigrtmax_9);
   check_signal_handler (F, SIGRTMAX-8, default_sigrtmax_8);
   check_signal_handler (F, SIGRTMAX-4, default_sigrtmax_4);
   check_signal_handler (F, SIGRTMAX-1, default_sigrtmax_1);
   check_signal_handler (F, SIGRTMAX, default_sigrtmax);
+#else
+  check_signal_handler (F, OUR_SIGRTMAX-9, default_sigrtmax_9);
+  check_signal_handler (F, OUR_SIGRTMAX-8, default_sigrtmax_8);
+  check_signal_handler (F, OUR_SIGRTMAX-4, default_sigrtmax_4);
+  check_signal_handler (F, OUR_SIGRTMAX-1, default_sigrtmax_1);
+  check_signal_handler (F, OUR_SIGRTMAX, default_sigrtmax);
+#endif
 
   if (!F->close_net_sockets) { F->close_net_sockets = default_close_network_sockets; }
   if (!F->cron) { F->cron = default_cron; }
@@ -573,8 +583,10 @@ void engine_startup (engine_t *E, server_functions_t *F) /* {{{ */ {
 
   precise_now_diff = get_utime_monotonic () - get_double_time ();
 
+#ifndef __FreeBSD__
   assert (SIGRTMAX == OUR_SIGRTMAX);
   assert (SIGRTMAX - SIGRTMIN >= 20);
+#endif
   
   E->sfd = 0;
   E->epoll_wait_timeout = DEFAULT_EPOLL_WAIT_TIMEOUT;
diff --git a/engine/engine.h b/engine/engine.h
index 776f56e3..d856d7a1 100644
--- a/engine/engine.h
+++ b/engine/engine.h
@@ -30,7 +30,12 @@
 
 // GLIBC DEFINES RTMAX as function
 // engine_init () asserts, that OUT_SIGRTMAX == SIGRTMAX
+// FreeBSD has SIGRTMAX=126 which doesn't fit in 64-bit signal mask, so use a lower value
+#ifdef __FreeBSD__
+#define OUR_SIGRTMAX 63
+#else
 #define OUR_SIGRTMAX 64
+#endif
 
 #include "common/common-stats.h"
 #include "engine/engine-rpc.h"
diff --git a/jobs/jobs.c b/jobs/jobs.c
index 68b7d531..923bd5d1 100644
--- a/jobs/jobs.c
+++ b/jobs/jobs.c
@@ -20,7 +20,9 @@
 */
 
 #define	_FILE_OFFSET_BITS        64
+#ifndef __FreeBSD__
 #define _XOPEN_SOURCE 500
+#endif
 #define _GNU_SOURCE 1
 
 #include <assert.h>
@@ -33,10 +35,22 @@
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
+#include <math.h>
+#ifdef __linux__
 #include <malloc.h>
 #include <sys/syscall.h>
-#include <math.h>
 #include <linux/futex.h>
+#endif
+#ifdef __FreeBSD__
+#include <stdlib.h>
+#include <pthread.h>
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#include <sys/thr.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+static pthread_mutex_t drand48_mutex = PTHREAD_MUTEX_INITIALIZER;
+#endif
 
 #include "common/proc-stat.h"
 #include "crc32.h"
@@ -369,6 +383,7 @@ __thread struct job_thread *this_job_thread;
 __thread job_t this_job;
 
 long int lrand48_j (void) {
+#ifdef __linux__
   if (this_job_thread) {
     long int t;
     lrand48_r (&this_job_thread->rand_data, &t);
@@ -376,9 +391,17 @@ long int lrand48_j (void) {
   } else {
     return lrand48 ();
   }
+#else
+  long int t;
+  pthread_mutex_lock (&drand48_mutex);
+  t = lrand48 ();
+  pthread_mutex_unlock (&drand48_mutex);
+  return t;
+#endif
 }
 
 long int mrand48_j (void) {
+#ifdef __linux__
   if (this_job_thread) {
     long int t;
     mrand48_r (&this_job_thread->rand_data, &t);
@@ -386,9 +409,17 @@ long int mrand48_j (void) {
   } else {
     return mrand48 ();
   }
+#else
+  long int t;
+  pthread_mutex_lock (&drand48_mutex);
+  t = mrand48 ();
+  pthread_mutex_unlock (&drand48_mutex);
+  return t;
+#endif
 }
 
 double drand48_j (void) {
+#ifdef __linux__
   if (this_job_thread) {
     double t;
     drand48_r (&this_job_thread->rand_data, &t);
@@ -396,6 +427,13 @@ double drand48_j (void) {
   } else {
     return drand48 ();
   }
+#else
+  double t;
+  pthread_mutex_lock (&drand48_mutex);
+  t = drand48 ();
+  pthread_mutex_unlock (&drand48_mutex);
+  return t;
+#endif
 }
 
 struct mp_queue MainJobQueue __attribute__((aligned(128)));
@@ -463,7 +501,13 @@ int create_job_thread_ex (int thread_class, void *(*thread_work)(void *)) {
   JT->id = i;
   assert (JT->job_queue);
 
+#ifdef __linux__
   srand48_r (rdtsc () ^ lrand48 (), &JT->rand_data);
+#else
+  pthread_mutex_lock (&drand48_mutex);
+  srand48 (rdtsc () ^ lrand48 ());
+  pthread_mutex_unlock (&drand48_mutex);
+#endif
 
 
   if (thread_class != JC_MAIN) {
@@ -889,7 +933,15 @@ void *job_thread_ex (void *arg, void (*work_one)(void *, int)) {
   assert (!(JT->thread_class & ~JC_MASK));
 
   get_this_thread_id ();
+#ifdef __linux__
   JT->thread_system_id = syscall (SYS_gettid);
+#elif defined(__FreeBSD__)
+  long tid;
+  thr_self (&tid);
+  JT->thread_system_id = (int) tid;
+#else
+  JT->thread_system_id = (int) pthread_self ();
+#endif
 
   set_job_interrupt_signal_handler ();
 
diff --git a/jobs/jobs.h b/jobs/jobs.h
index f249a0a4..35a90571 100644
--- a/jobs/jobs.h
+++ b/jobs/jobs.h
@@ -232,7 +232,9 @@ struct job_thread {
   long long jobs_created;
   long long jobs_active;
   int thread_system_id;
+#ifdef __linux__
   struct drand48_data rand_data;
+#endif
   job_t timer_manager;
   double wakeup_time;
   struct job_class *job_class;
diff --git a/mtproto/mtproto-proxy.c b/mtproto/mtproto-proxy.c
index e28f36fc..18b55a99 100644
--- a/mtproto/mtproto-proxy.c
+++ b/mtproto/mtproto-proxy.c
@@ -26,6 +26,7 @@
 
 #include <assert.h>
 #include <errno.h>
+#include <signal.h>
 #include <string.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -2098,9 +2099,11 @@ void mtfront_pre_loop (void) {
         listening_connection_job_t LC = Events[http_sfd[i]].data;
         assert (LC);
         CONN_INFO(LC)->window_clamp = window_clamp;
+#ifdef TCP_WINDOW_CLAMP
         if (setsockopt (http_sfd[i], IPPROTO_TCP, TCP_WINDOW_CLAMP, &window_clamp, 4) < 0) {
           vkprintf (0, "error while setting window size for socket #%d to %d: %m\n", http_sfd[i], window_clamp);
         }
+#endif
       }
     }
     // create_all_outbound_connections ();
diff --git a/net/net-connections.c b/net/net-connections.c
index d7a0cd7e..5a4cb28e 100644
--- a/net/net-connections.c
+++ b/net/net-connections.c
@@ -46,6 +46,11 @@
 #include <time.h>
 #include <unistd.h>
 
+/* libepoll-shim on FreeBSD defines close as a macro, which conflicts with struct members named 'close' */
+#ifdef close
+#undef close
+#endif
+
 #include "crc32.h"
 #include "jobs/jobs.h"
 #include "net/net-events.h"
@@ -321,8 +326,12 @@ void connection_write_close (connection_job_t C) /* {{{ */ {
 
 /* qack {{{ */
 static inline void disable_qack (int fd) {
+#ifdef TCP_QUICKACK
   vkprintf (2, "disable TCP_QUICKACK for %d\n", fd);
   assert (setsockopt (fd, IPPROTO_TCP, TCP_QUICKACK, (int[]){0}, sizeof (int)) >= 0);
+#else
+  (void)fd;
+#endif
 }
 
 static inline void cond_disable_qack (socket_connection_job_t C) {
@@ -737,6 +746,7 @@ connection_job_t alloc_new_connection (int cfd, conn_target_job_t CTJ, listening
           }
         }
       }
+#ifdef TCP_WINDOW_CLAMP
       if (c->window_clamp) {
         if (setsockopt (cfd, IPPROTO_TCP, TCP_WINDOW_CLAMP, &c->window_clamp, 4) < 0) {
           vkprintf (0, "error while setting window size for socket #%d to %d: %m\n", cfd, c->window_clamp);
@@ -748,6 +758,7 @@ connection_job_t alloc_new_connection (int cfd, conn_target_job_t CTJ, listening
           vkprintf (2, "window clamp for socket #%d is %d, receive buffer is %d\n", cfd, t1, t2);
         }
       }
+#endif
     }
 
     alloc_new_socket_connection (C);
diff --git a/net/net-crypto-dh.c b/net/net-crypto-dh.c
index b9aaa175..f16bb514 100644
--- a/net/net-crypto-dh.c
+++ b/net/net-crypto-dh.c
@@ -20,7 +20,9 @@
     
 */
 #define	_FILE_OFFSET_BITS	64
+#ifndef __FreeBSD__
 #define _XOPEN_SOURCE 500
+#endif
 
 
 #include <assert.h>
diff --git a/net/net-events.c b/net/net-events.c
index ba3e800c..4e6cfc3f 100644
--- a/net/net-events.c
+++ b/net/net-events.c
@@ -36,7 +36,9 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/epoll.h>
+#ifdef __linux__
 #include <sys/io.h>
+#endif
 #include <sys/socket.h>
 #include <time.h>
 #include <unistd.h>
@@ -568,7 +570,9 @@ int server_socket (int port, struct in_addr in_addr, int backlog, int mode) {
   if (mode & SM_UDP) {
     maximize_sndbuf (socket_fd, 0);
     maximize_rcvbuf (socket_fd, 0);
+#ifdef IP_RECVERR
     setsockopt (socket_fd, SOL_IP, IP_RECVERR, &flags, sizeof (flags));
+#endif
   } else {
     setsockopt (socket_fd, SOL_SOCKET, SO_REUSEADDR, &flags, sizeof (flags));
     if (tcp_maximize_buffers) {
@@ -644,7 +648,9 @@ int client_socket (in_addr_t in_addr, int port, int mode) {
   if (mode & SM_UDP) {
     maximize_sndbuf (socket_fd, 0);
     maximize_rcvbuf (socket_fd, 0);
+#ifdef IP_RECVERR
     setsockopt (socket_fd, SOL_IP, IP_RECVERR, &flags, sizeof (flags));
+#endif
   } else {
     setsockopt (socket_fd, SOL_SOCKET, SO_REUSEADDR, &flags, sizeof (flags));
     if (tcp_maximize_buffers) {
diff --git a/net/net-events.h b/net/net-events.h
index 24e92c0f..2b1deb41 100644
--- a/net/net-events.h
+++ b/net/net-events.h
@@ -24,6 +24,7 @@
 
 #pragma once
 
+#include <sys/socket.h>
 #include <netinet/in.h>
 
 #ifndef EPOLLRDHUP