diff --git a/.github/workflows/common-workflow.yml b/.github/workflows/common-workflow.yml
index 701fcaa..d0b0811 100644
--- a/.github/workflows/common-workflow.yml
+++ b/.github/workflows/common-workflow.yml
@@ -45,7 +45,7 @@ jobs:
           pwd
           export PROJECT_ROOT_DIR="."
           ls build/examples/*_example
-          find build/examples -name "*_example" -not -name "zmq_example" | xargs -I {} -n 1 -t  bash -c {}
+          find build/examples -name "*_example" -not -name "zmq_*" | xargs -I {} -n 1 -t  bash -c {}
 
 
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index d330d16..14ed946 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -148,11 +148,12 @@ endif()
 add_subdirectory(core)
 add_subdirectory(file_io)
 add_subdirectory(utils)
+add_subdirectory(network_io)
 
 
 #Overall target to link to when using the library
 add_library(aare INTERFACE) 
-target_link_libraries(aare INTERFACE core file_io utils)
+target_link_libraries(aare INTERFACE core file_io utils network_io)
 target_include_directories(aare INTERFACE 
     $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
     $<INSTALL_INTERFACE:include>
diff --git a/aare-environment.yml b/aare-environment.yml
index d2babc2..b8112e2 100644
--- a/aare-environment.yml
+++ b/aare-environment.yml
@@ -5,6 +5,6 @@ channels:
 dependencies:
   - fmt
   - pybind11
-  - nlohmann_json
+  - nlohmann_json # should be removed
   - catch2
   - zeromq
diff --git a/core/CMakeLists.txt b/core/CMakeLists.txt
index 0a08c84..460e0f5 100644
--- a/core/CMakeLists.txt
+++ b/core/CMakeLists.txt
@@ -4,7 +4,6 @@ set(SourceFiles
     ${CMAKE_CURRENT_SOURCE_DIR}/src/defs.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/DType.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/Frame.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/src/ZmqSocket.cpp
 )
 
 
@@ -12,7 +11,7 @@ add_library(core STATIC ${SourceFiles})
 target_include_directories(core PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
 
 
-target_link_libraries(core PUBLIC fmt::fmt PRIVATE aare_compiler_flags utils libzmq)
+target_link_libraries(core PUBLIC fmt::fmt PRIVATE aare_compiler_flags utils )
 
 if (AARE_PYTHON_BINDINGS)
 set_property(TARGET core PROPERTY POSITION_INDEPENDENT_CODE ON)
diff --git a/core/include/aare/ZmqSocket.hpp b/core/include/aare/ZmqSocket.hpp
deleted file mode 100644
index 67859df..0000000
--- a/core/include/aare/ZmqSocket.hpp
+++ /dev/null
@@ -1,93 +0,0 @@
-#pragma once
-
-#include <array>
-#include <cstdint>
-#include <map>
-#include <string>
-
-// Socket to receive data from a ZMQ publisher
-// needs to be in sync with the main library (or maybe better use the versioning in the header)
-
-// forward declare zmq_msg_t to avoid including zmq.h in the header
-class zmq_msg_t;
-
-namespace aare {
-
-/** zmq header structure (from slsDetectorPackage)*/
-struct zmqHeader {
-    /** true if incoming data, false if end of acquisition */
-    bool data{true};
-    uint32_t jsonversion{0};
-    uint32_t dynamicRange{0};
-    uint64_t fileIndex{0};
-    /** number of detectors/port in x axis */
-    uint32_t ndetx{0};
-    /** number of detectors/port in y axis */
-    uint32_t ndety{0};
-    /** number of pixels/channels in x axis for this zmq socket */
-    uint32_t npixelsx{0};
-    /** number of pixels/channels in y axis for this zmq socket */
-    uint32_t npixelsy{0};
-    /** number of bytes for an image in this socket */
-    uint32_t imageSize{0};
-    /** frame number from detector */
-    uint64_t acqIndex{0};
-    /** frame index (starting at 0 for each acquisition) */
-    uint64_t frameIndex{0};
-    /** progress in percentage */
-    double progress{0};
-    /** file name prefix */
-    std::string fname;
-    /** header from detector */
-    uint64_t frameNumber{0};
-    uint32_t expLength{0};
-    uint32_t packetNumber{0};
-    uint64_t detSpec1{0};
-    uint64_t timestamp{0};
-    uint16_t modId{0};
-    uint16_t row{0};
-    uint16_t column{0};
-    uint16_t detSpec2{0};
-    uint32_t detSpec3{0};
-    uint16_t detSpec4{0};
-    uint8_t detType{0};
-    uint8_t version{0};
-    /** if rows of image should be flipped */
-    int flipRows{0};
-    /** quad type (eiger hardware specific) */
-    uint32_t quad{0};
-    /** true if complete image, else missing packets */
-    bool completeImage{false};
-    /** additional json header */
-    std::map<std::string, std::string> addJsonHeader;
-    /** (xmin, xmax, ymin, ymax) roi only in files written */
-    std::array<int, 4> rx_roi{};
-};
-
-class ZmqSocket {
-    void *m_context{nullptr};
-    void *m_socket{nullptr};
-    std::string m_endpoint;
-    int m_zmq_hwm{1000};
-    int m_timeout_ms{1000};
-    constexpr static size_t m_max_header_size = 1024;
-    char *m_header_buffer = new char[m_max_header_size];
-
-    bool decode_header(zmqHeader &h);
-
-  public:
-    ZmqSocket(const std::string &endpoint);
-    ~ZmqSocket();
-    ZmqSocket(const ZmqSocket &) = delete;
-    ZmqSocket operator=(const ZmqSocket &) = delete;
-    ZmqSocket(ZmqSocket &&) = delete;
-
-    void connect();
-    void disconnect();
-    void set_zmq_hwm(int hwm);
-    void set_timeout_ms(int n);
-
-    int receive(zmqHeader &header, std::byte *data);
-};
-
-} // namespace aare
\ No newline at end of file
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 2d8bb9c..dfe6150 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -1,6 +1,6 @@
 
-set(EXAMPLE_LIST "json_example;logger_example;numpy_read_example;multiport_example;raw_example;zmq_example;")
-set(EXAMPLE_LIST "${EXAMPLE_LIST};mythen_example;numpy_write_example")
+set(EXAMPLE_LIST "json_example;logger_example;numpy_read_example;multiport_example;raw_example;")
+set(EXAMPLE_LIST "${EXAMPLE_LIST};mythen_example;numpy_write_example;zmq_receiver_example;zmq_sender_example;")
 foreach(example ${EXAMPLE_LIST})
     add_executable(${example} ${example}.cpp)
     target_link_libraries(${example} PUBLIC aare PRIVATE aare_compiler_flags)
diff --git a/examples/zmq_example.cpp b/examples/zmq_example.cpp
deleted file mode 100644
index 05747e6..0000000
--- a/examples/zmq_example.cpp
+++ /dev/null
@@ -1,16 +0,0 @@
-#include "aare/ZmqSocket.hpp"
-#include <fmt/core.h>
-#include <string>
-
-int main() {
-    std::string endpoint = "tcp://localhost:5555";
-    aare::ZmqSocket socket(endpoint);
-    socket.connect();
-    char *data = new char[1024 * 1024 * 10];
-    aare::zmqHeader header;
-    while (true) {
-        int rc = socket.receive(header, reinterpret_cast<std::byte *>(data));
-    }
-    delete[] data;
-    return 0;
-}
\ No newline at end of file
diff --git a/examples/zmq_receiver_example.cpp b/examples/zmq_receiver_example.cpp
new file mode 100644
index 0000000..888d640
--- /dev/null
+++ b/examples/zmq_receiver_example.cpp
@@ -0,0 +1,27 @@
+#include "aare/ZmqSocketReceiver.hpp"
+#include <cassert>
+#include <fmt/core.h>
+#include <string>
+
+int main() {
+    std::string endpoint = "tcp://localhost:5555";
+    aare::ZmqSocketReceiver socket(endpoint);
+    socket.connect();
+    char *data = new char[1024 * 1024 * 10];
+    aare::ZmqHeader header;
+
+    while (true) {
+        int rc = socket.receive(header, reinterpret_cast<std::byte *>(data));
+        aare::logger::info("Received bytes", rc, "Received header: ", header.to_string());
+        auto *data_int = reinterpret_cast<uint32_t *>(data);
+        for (uint32_t i = 0; i < header.npixelsx; i++) {
+            for (uint32_t j = 0; j < header.npixelsy; j++) {
+                // verify that the sent data is correct
+                assert(data_int[i * header.npixelsy + j] == i + j);
+            }
+        }
+        aare::logger::info("Frame verified");
+    }
+    delete[] data;
+    return 0;
+}
\ No newline at end of file
diff --git a/examples/zmq_sender_example.cpp b/examples/zmq_sender_example.cpp
new file mode 100644
index 0000000..5739d91
--- /dev/null
+++ b/examples/zmq_sender_example.cpp
@@ -0,0 +1,37 @@
+#include "aare/Frame.hpp"
+#include "aare/ZmqSocketSender.hpp"
+#include "aare/utils/logger.hpp"
+
+#include <fmt/core.h>
+#include <string>
+#include <unistd.h> // sleep
+using namespace aare;
+
+int main() {
+    std::string endpoint = "tcp://*:5555";
+    aare::ZmqSocketSender socket(endpoint);
+    socket.bind();
+    Frame frame(1024, 1024, sizeof(uint32_t) * 8);
+    for (int i = 0; i < 1024; i++) {
+        for (int j = 0; j < 1024; j++) {
+            frame.set(i, j, i + j);
+        }
+    }
+    aare::ZmqHeader header;
+    header.npixelsx = 1024;
+    header.npixelsy = 1024;
+    header.imageSize = sizeof(uint32_t) * 1024 * 1024;
+    header.dynamicRange = 32;
+
+    int i = 0;
+    while (true) {
+        aare::logger::info("Sending frame:", i++);
+        aare::logger::info("Header size:", sizeof(header.to_string()));
+        aare::logger::info("Frame size:", frame.size(), "\n");
+
+        int rc = socket.send(header, frame.data(), frame.size());
+        aare::logger::info("Sent bytes", rc);
+        sleep(1);
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/file_io/include/aare/RawFile.hpp b/file_io/include/aare/RawFile.hpp
index 7b8e450..f5bd4de 100644
--- a/file_io/include/aare/RawFile.hpp
+++ b/file_io/include/aare/RawFile.hpp
@@ -12,7 +12,10 @@ class RawFile : public FileInterface {
 
   public:
     std::filesystem::path m_fname; // TO be made private!
-    void write(Frame &frame) override{};
+
+    // pragma to ignore warnings
+    void write(Frame &frame) override { throw std::runtime_error("Not implemented"); };
+
     Frame read() override { return get_frame(this->current_frame++); };
     std::vector<Frame> read(size_t n_frames) override;
     void read_into(std::byte *image_buf) override { return get_frame_into(this->current_frame++, image_buf); };
diff --git a/file_io/src/SubFile.cpp b/file_io/src/SubFile.cpp
index eca4ea5..f25371f 100644
--- a/file_io/src/SubFile.cpp
+++ b/file_io/src/SubFile.cpp
@@ -89,7 +89,7 @@ template <typename DataType> size_t SubFile::read_impl_flip(std::byte *buffer) {
 
 size_t SubFile::frame_number(int frame_index) {
     sls_detector_header h{};
-    FILE *fp = fopen(this->m_fname.c_str(), "r");
+    fp = fopen(this->m_fname.c_str(), "r");
     if (!fp)
         throw std::runtime_error(fmt::format("Could not open: {} for reading", m_fname.c_str()));
     fseek(fp, (sizeof(sls_detector_header) + bytes_per_part()) * frame_index, SEEK_SET);
diff --git a/file_io/test/NumpyFile.test.cpp b/file_io/test/NumpyFile.test.cpp
index 60a5afd..4468b7d 100644
--- a/file_io/test/NumpyFile.test.cpp
+++ b/file_io/test/NumpyFile.test.cpp
@@ -19,7 +19,7 @@ TEST_CASE("Read a 1D numpy file with int32 data type") {
 
     // use the load function to read the full file into a NDArray
     auto data = f.load<int32_t, 1>();
-    for (size_t i = 0; i < 10; i++) {
+    for (int32_t i = 0; i < 10; i++) {
         REQUIRE(data(i) == i);
     }
 }
diff --git a/network_io/CMakeLists.txt b/network_io/CMakeLists.txt
new file mode 100644
index 0000000..7d544dd
--- /dev/null
+++ b/network_io/CMakeLists.txt
@@ -0,0 +1,38 @@
+
+FetchContent_Declare(
+    simdjson
+    GIT_REPOSITORY https://github.com/simdjson/simdjson.git
+    GIT_TAG  tags/v3.8.0
+    GIT_SHALLOW TRUE
+)
+
+FetchContent_MakeAvailable(simdjson)
+# hide simdjson warnings by making the includes system includes
+get_target_property(_inc simdjson INTERFACE_INCLUDE_DIRECTORIES)
+target_include_directories(simdjson SYSTEM INTERFACE ${_inc})
+
+
+add_library(network_io STATIC 
+    src/ZmqSocketReceiver.cpp
+    src/ZmqSocketSender.cpp
+    src/ZmqSocket.cpp
+    src/ZmqHeader.cpp
+    )
+
+
+
+target_include_directories(network_io PUBLIC include)
+target_link_libraries(network_io PRIVATE   libzmq fmt::fmt core utils   aare_compiler_flags )
+target_link_libraries(network_io PUBLIC simdjson)
+
+if(AARE_PYTHON_BINDINGS)
+set_property(TARGET file_io PROPERTY POSITION_INDEPENDENT_CODE ON)
+endif()
+
+if(AARE_TESTS)
+    set(TestSources 
+    ${CMAKE_CURRENT_SOURCE_DIR}/test/ZmqHeader.test.cpp
+    )
+    target_sources(tests PRIVATE ${TestSources} )
+    target_link_libraries(tests PRIVATE network_io core utils)
+endif()
\ No newline at end of file
diff --git a/network_io/include/aare/ZmqHeader.hpp b/network_io/include/aare/ZmqHeader.hpp
new file mode 100644
index 0000000..6096282
--- /dev/null
+++ b/network_io/include/aare/ZmqHeader.hpp
@@ -0,0 +1,138 @@
+#include "aare/utils/logger.hpp"
+#include "simdjson.h"
+#include <array>
+#include <cstdint>
+#include <map>
+#include <string>
+namespace simdjson {
+/**
+ * @brief cast a simdjson::ondemand::value to a std::array<int,4>
+ * useful for writing rx_roi from json header
+ */
+template <> simdjson_inline simdjson::simdjson_result<std::array<int, 4>> simdjson::ondemand::value::get() noexcept {
+    ondemand::array array;
+    auto error = get_array().get(array);
+    if (error) {
+        return error;
+    }
+    std::array<int, 4> arr;
+    int i = 0;
+    for (auto v : array) {
+        int64_t val;
+        error = v.get_int64().get(val);
+
+        if (error) {
+            return error;
+        }
+        arr[i++] = val;
+    }
+    return arr;
+}
+
+/**
+ * @brief cast a simdjson::ondemand::value to a uint32_t
+ * adds a check for 32bit overflow
+ */
+template <> simdjson_inline simdjson::simdjson_result<uint32_t> simdjson::ondemand::value::get() noexcept {
+    size_t val;
+    auto error = get_uint64().get(val);
+    if (error) {
+        return error;
+    }
+    if (val > std::numeric_limits<uint32_t>::max()) {
+        return 1;
+    }
+    return static_cast<uint32_t>(val);
+}
+
+/**
+ * @brief cast a simdjson::ondemand::value to a std::map<std::string, std::string>
+ */
+template <>
+simdjson_inline simdjson::simdjson_result<std::map<std::string, std::string>>
+simdjson::ondemand::value::get() noexcept {
+    std::map<std::string, std::string> map;
+    ondemand::object obj;
+    auto error = get_object().get(obj);
+    if (error) {
+        return error;
+    }
+    for (auto field : obj) {
+        simdjson::ondemand::raw_json_string tmp;
+        error = field.key().get(tmp);
+        if (error) {
+            return error;
+        }
+        error = field.value().get(tmp);
+        if (error) {
+            return error;
+        }
+        std::string_view key_view = field.unescaped_key();
+        std::string key_str(key_view.data(), key_view.size());
+        std::string_view value_view = field.value().get_string();
+        map[key_str] = {value_view.data(), value_view.size()};
+    }
+    return map;
+}
+
+} // namespace simdjson
+
+namespace aare {
+
+/** zmq header structure (from slsDetectorPackage)*/
+struct ZmqHeader {
+    /** true if incoming data, false if end of acquisition */
+    bool data{true};
+    uint32_t jsonversion{0};
+    uint32_t dynamicRange{0};
+    uint64_t fileIndex{0};
+    /** number of detectors/port in x axis */
+    uint32_t ndetx{0};
+    /** number of detectors/port in y axis */
+    uint32_t ndety{0};
+    /** number of pixels/channels in x axis for this zmq socket */
+    uint32_t npixelsx{0};
+    /** number of pixels/channels in y axis for this zmq socket */
+    uint32_t npixelsy{0};
+    /** number of bytes for an image in this socket */
+    uint32_t imageSize{0};
+    /** frame number from detector */
+    uint64_t acqIndex{0};
+    /** frame index (starting at 0 for each acquisition) */
+    uint64_t frameIndex{0};
+    /** progress in percentage */
+    double progress{0};
+    /** file name prefix */
+    std::string fname;
+    /** header from detector */
+    uint64_t frameNumber{0};
+    uint32_t expLength{0};
+    uint32_t packetNumber{0};
+    uint64_t detSpec1{0};
+    uint64_t timestamp{0};
+    uint16_t modId{0};
+    uint16_t row{0};
+    uint16_t column{0};
+    uint16_t detSpec2{0};
+    uint32_t detSpec3{0};
+    uint16_t detSpec4{0};
+    uint8_t detType{0};
+    uint8_t version{0};
+    /** if rows of image should be flipped */
+    int flipRows{0};
+    /** quad type (eiger hardware specific) */
+    uint32_t quad{0};
+    /** true if complete image, else missing packets */
+    bool completeImage{false};
+    /** additional json header */
+    std::map<std::string, std::string> addJsonHeader;
+    /** (xmin, xmax, ymin, ymax) roi only in files written */
+    std::array<int, 4> rx_roi{};
+
+    /** serialize struct to json string */
+    std::string to_string() const;
+    void from_string(std::string &s);
+    // compare operator
+    bool operator==(const ZmqHeader &other) const;
+};
+} // namespace aare
\ No newline at end of file
diff --git a/network_io/include/aare/ZmqSocket.hpp b/network_io/include/aare/ZmqSocket.hpp
new file mode 100644
index 0000000..474e054
--- /dev/null
+++ b/network_io/include/aare/ZmqSocket.hpp
@@ -0,0 +1,40 @@
+#pragma once
+
+#include <array>
+#include <map>
+#include <string>
+
+// Socket to receive data from a ZMQ publisher
+// needs to be in sync with the main library (or maybe better use the versioning in the header)
+
+// forward declare zmq_msg_t to avoid including zmq.h in the header
+class zmq_msg_t;
+
+namespace aare {
+
+class ZmqSocket {
+  protected:
+    void *m_context{nullptr};
+    void *m_socket{nullptr};
+    std::string m_endpoint;
+    int m_zmq_hwm{1000};
+    int m_timeout_ms{1000};
+    size_t m_potential_frame_size{1024 * 1024};
+    constexpr static size_t m_max_header_size = 1024;
+    char *m_header_buffer = new char[m_max_header_size];
+
+  public:
+    ZmqSocket() = default;
+    ~ZmqSocket();
+
+    ZmqSocket(const ZmqSocket &) = delete;
+    ZmqSocket operator=(const ZmqSocket &) = delete;
+    ZmqSocket(ZmqSocket &&) = delete;
+
+    void disconnect();
+    void set_zmq_hwm(int hwm);
+    void set_timeout_ms(int n);
+    void set_potential_frame_size(size_t size);
+};
+
+} // namespace aare
\ No newline at end of file
diff --git a/network_io/include/aare/ZmqSocketReceiver.hpp b/network_io/include/aare/ZmqSocketReceiver.hpp
new file mode 100644
index 0000000..894c750
--- /dev/null
+++ b/network_io/include/aare/ZmqSocketReceiver.hpp
@@ -0,0 +1,26 @@
+#pragma once
+
+#include "ZmqHeader.hpp"
+#include "ZmqSocket.hpp"
+
+#include <array>
+#include <cstdint>
+#include <map>
+#include <string>
+
+// Socket to receive data from a ZMQ publisher
+// needs to be in sync with the main library (or maybe better use the versioning in the header)
+
+// forward declare zmq_msg_t to avoid including zmq.h in the header
+class zmq_msg_t;
+
+namespace aare {
+
+class ZmqSocketReceiver : public ZmqSocket {
+  public:
+    ZmqSocketReceiver(const std::string &endpoint);
+    void connect();
+    size_t receive(ZmqHeader &header, std::byte *data, bool serialized_header = false);
+};
+
+} // namespace aare
\ No newline at end of file
diff --git a/network_io/include/aare/ZmqSocketSender.hpp b/network_io/include/aare/ZmqSocketSender.hpp
new file mode 100644
index 0000000..ce2b91f
--- /dev/null
+++ b/network_io/include/aare/ZmqSocketSender.hpp
@@ -0,0 +1,12 @@
+#pragma once
+#include "ZmqHeader.hpp"
+#include "ZmqSocket.hpp"
+
+namespace aare {
+class ZmqSocketSender : public ZmqSocket {
+  public:
+    ZmqSocketSender(const std::string &endpoint);
+    void bind();
+    size_t send(ZmqHeader &header, const std::byte *data, size_t size, bool serialize_header = false);
+};
+} // namespace aare
\ No newline at end of file
diff --git a/network_io/src/ZmqHeader.cpp b/network_io/src/ZmqHeader.cpp
new file mode 100644
index 0000000..3eff459
--- /dev/null
+++ b/network_io/src/ZmqHeader.cpp
@@ -0,0 +1,200 @@
+
+#include "aare/ZmqHeader.hpp"
+
+#include "simdjson.h"
+
+using namespace simdjson;
+
+// helper functions to write json
+// append to string for better performance (not tested)
+
+/**
+ * @brief write a digit to a string
+ * takes key and value and outputs->"key": value,
+ * @tparam T type of value (int, uint32_t, ...)
+ * @param s string to append to
+ * @param key key to write
+ * @param value value to write
+ * @return void
+ * @note
+ * - can't use concepts here because we are using c++17
+ */
+template <typename T> void write_digit(std::string &s, const std::string &key, const T &value) {
+    s += "\"";
+    s += key;
+    s += "\": ";
+    s += std::to_string(value);
+    s += ", ";
+}
+void write_str(std::string &s, const std::string &key, const std::string &value) {
+    s += "\"";
+    s += key;
+    s += "\": \"";
+    s += value;
+    s += "\", ";
+}
+void write_map(std::string &s, const std::string &key, const std::map<std::string, std::string> &value) {
+    s += "\"";
+    s += key;
+    s += "\": {";
+    for (auto &kv : value) {
+        write_str(s, kv.first, kv.second);
+    }
+    // remove last comma or trailing spaces
+    for (int i = s.size() - 1; i >= 0; i--) {
+        if (s[i] == ',' or s[i] == ' ') {
+            s.pop_back();
+        } else
+            break;
+    }
+    s += "}, ";
+}
+void write_array(std::string &s, const std::string &key, const std::array<int, 4> &value) {
+    s += "\"";
+    s += key;
+    s += "\": [";
+    s += std::to_string(value[0]);
+    s += ", ";
+    s += std::to_string(value[1]);
+    s += ", ";
+    s += std::to_string(value[2]);
+    s += ", ";
+    s += std::to_string(value[3]);
+    s += "], ";
+}
+
+namespace aare {
+
+std::string ZmqHeader::to_string() const {
+    std::string s = "";
+    s.reserve(1024);
+    s += "{";
+    write_digit(s, "data", data ? 1 : 0);
+    write_digit(s, "jsonversion", jsonversion);
+    write_digit(s, "dynamicRange", dynamicRange);
+    write_digit(s, "fileIndex", fileIndex);
+    write_digit(s, "ndetx", ndetx);
+    write_digit(s, "ndety", ndety);
+    write_digit(s, "npixelsx", npixelsx);
+    write_digit(s, "npixelsy", npixelsy);
+    write_digit(s, "imageSize", imageSize);
+    write_digit(s, "acqIndex", acqIndex);
+    write_digit(s, "frameIndex", frameIndex);
+    write_digit(s, "progress", progress);
+    write_str(s, "fname", fname);
+    write_digit(s, "frameNumber", frameNumber);
+    write_digit(s, "expLength", expLength);
+    write_digit(s, "packetNumber", packetNumber);
+    write_digit(s, "detSpec1", detSpec1);
+    write_digit(s, "timestamp", timestamp);
+    write_digit(s, "modId", modId);
+    write_digit(s, "row", row);
+    write_digit(s, "column", column);
+    write_digit(s, "detSpec2", detSpec2);
+    write_digit(s, "detSpec3", detSpec3);
+    write_digit(s, "detSpec4", detSpec4);
+    write_digit(s, "detType", detType);
+    write_digit(s, "version", version);
+    write_digit(s, "flipRows", flipRows);
+    write_digit(s, "quad", quad);
+    write_digit(s, "completeImage", completeImage ? 1 : 0);
+    write_map(s, "addJsonHeader", addJsonHeader);
+    write_array(s, "rx_roi", rx_roi);
+    // remove last comma
+    s.pop_back();
+    s.pop_back();
+
+    s += "}";
+    return s;
+}
+
+void ZmqHeader::from_string(std::string &s) {
+
+    simdjson::padded_string ps(s.c_str(), s.size());
+    ondemand::parser parser;
+    ondemand::document doc = parser.iterate(ps);
+    ondemand::object object = doc.get_object();
+
+    for (auto field : object) {
+        std::string_view key = field.unescaped_key();
+
+        if (key == "data") {
+            data = uint64_t(field.value()) ? true : false;
+        } else if (key == "jsonversion") {
+            jsonversion = uint32_t(field.value());
+        } else if (key == "dynamicRange") {
+            dynamicRange = uint32_t(field.value());
+        } else if (key == "fileIndex") {
+            fileIndex = uint64_t(field.value());
+        } else if (key == "ndetx") {
+            ndetx = uint32_t(field.value());
+        } else if (key == "ndety") {
+            ndety = uint32_t(field.value());
+        } else if (key == "npixelsx") {
+            npixelsx = uint32_t(field.value());
+        } else if (key == "npixelsy") {
+            npixelsy = uint32_t(field.value());
+        } else if (key == "imageSize") {
+            imageSize = uint32_t(field.value());
+        } else if (key == "acqIndex") {
+            acqIndex = uint64_t(field.value());
+        } else if (key == "frameIndex") {
+            frameIndex = uint64_t(field.value());
+        } else if (key == "progress") {
+            progress = field.value().get_double();
+        } else if (key == "fname") {
+            std::string_view tmp = field.value().get_string();
+            fname = {tmp.begin(), tmp.end()};
+        } else if (key == "frameNumber") {
+            frameNumber = uint64_t(field.value());
+        } else if (key == "expLength") {
+            expLength = uint32_t(field.value());
+        } else if (key == "packetNumber") {
+            packetNumber = uint32_t(field.value());
+        } else if (key == "detSpec1") {
+            detSpec1 = uint64_t(field.value());
+        } else if (key == "timestamp") {
+            timestamp = uint64_t(field.value());
+        } else if (key == "modId") {
+            modId = uint32_t(field.value());
+        } else if (key == "row") {
+            row = uint32_t(field.value());
+        } else if (key == "column") {
+            column = uint32_t(field.value());
+        } else if (key == "detSpec2") {
+            detSpec2 = uint32_t(field.value());
+        } else if (key == "detSpec3") {
+            detSpec3 = uint32_t(field.value());
+        } else if (key == "detSpec4") {
+            detSpec4 = uint32_t(field.value());
+        } else if (key == "detType") {
+            detType = uint32_t(field.value());
+        } else if (key == "version") {
+            version = uint32_t(field.value());
+        } else if (key == "flipRows") {
+            flipRows = uint32_t(field.value());
+        } else if (key == "quad") {
+            quad = uint32_t(field.value());
+        } else if (key == "completeImage") {
+            completeImage = uint64_t(field.value()) ? true : false;
+        } else if (key == "addJsonHeader") {
+            addJsonHeader = std::map<std::string, std::string>(field.value());
+        } else if (key == "rx_roi") {
+            rx_roi = std::array<int, 4>(field.value());
+        }
+    }
+}
+bool ZmqHeader::operator==(const ZmqHeader &other) const {
+    return data == other.data && jsonversion == other.jsonversion && dynamicRange == other.dynamicRange &&
+           fileIndex == other.fileIndex && ndetx == other.ndetx && ndety == other.ndety && npixelsx == other.npixelsx &&
+           npixelsy == other.npixelsy && imageSize == other.imageSize && acqIndex == other.acqIndex &&
+           frameIndex == other.frameIndex && progress == other.progress && fname == other.fname &&
+           frameNumber == other.frameNumber && expLength == other.expLength && packetNumber == other.packetNumber &&
+           detSpec1 == other.detSpec1 && timestamp == other.timestamp && modId == other.modId && row == other.row &&
+           column == other.column && detSpec2 == other.detSpec2 && detSpec3 == other.detSpec3 &&
+           detSpec4 == other.detSpec4 && detType == other.detType && version == other.version &&
+           flipRows == other.flipRows && quad == other.quad && completeImage == other.completeImage &&
+           addJsonHeader == other.addJsonHeader && rx_roi == other.rx_roi;
+}
+
+} // namespace aare
\ No newline at end of file
diff --git a/network_io/src/ZmqSocket.cpp b/network_io/src/ZmqSocket.cpp
new file mode 100644
index 0000000..47ddf79
--- /dev/null
+++ b/network_io/src/ZmqSocket.cpp
@@ -0,0 +1,26 @@
+#include "aare/ZmqSocket.hpp"
+#include <fmt/core.h>
+#include <zmq.h>
+
+namespace aare {
+
+void ZmqSocket::disconnect() {
+    zmq_close(m_socket);
+    zmq_ctx_destroy(m_context);
+    m_socket = nullptr;
+    m_context = nullptr;
+}
+
+ZmqSocket::~ZmqSocket() {
+    if (m_socket)
+        disconnect();
+    delete[] m_header_buffer;
+}
+
+void ZmqSocket::set_zmq_hwm(int hwm) { m_zmq_hwm = hwm; }
+
+void ZmqSocket::set_timeout_ms(int n) { m_timeout_ms = n; }
+
+void ZmqSocket::set_potential_frame_size(size_t size) { m_potential_frame_size = size; }
+
+} // namespace aare
diff --git a/core/src/ZmqSocket.cpp b/network_io/src/ZmqSocketReceiver.cpp
similarity index 57%
rename from core/src/ZmqSocket.cpp
rename to network_io/src/ZmqSocketReceiver.cpp
index ab4fb2b..2d395ea 100644
--- a/core/src/ZmqSocket.cpp
+++ b/network_io/src/ZmqSocketReceiver.cpp
@@ -1,14 +1,17 @@
-#include "aare/ZmqSocket.hpp"
+#include "aare/ZmqSocketReceiver.hpp"
+#include "aare/utils/logger.hpp"
+
 #include <fmt/core.h>
 #include <zmq.h>
 
 namespace aare {
 
-ZmqSocket::ZmqSocket(const std::string &endpoint) : m_endpoint(endpoint) {
+ZmqSocketReceiver::ZmqSocketReceiver(const std::string &endpoint) {
+    m_endpoint = endpoint;
     memset(m_header_buffer, 0, m_max_header_size);
 }
 
-void ZmqSocket::connect() {
+void ZmqSocketReceiver::connect() {
     m_context = zmq_ctx_new();
     m_socket = zmq_socket(m_context, ZMQ_SUB);
     fmt::print("Setting ZMQ_RCVHWM to {}\n", m_zmq_hwm);
@@ -16,7 +19,7 @@ void ZmqSocket::connect() {
     if (rc)
         throw std::runtime_error(fmt::format("Could not set ZMQ_RCVHWM: {}", strerror(errno)));
 
-    int bufsize = 1024 * 1024 * m_zmq_hwm;
+    int bufsize = m_potential_frame_size * m_zmq_hwm;
     fmt::print("Setting ZMQ_RCVBUF to: {} MB\n", bufsize / (1024 * 1024));
     rc = zmq_setsockopt(m_socket, ZMQ_RCVBUF, &bufsize, sizeof(bufsize));
     if (rc)
@@ -26,37 +29,29 @@ void ZmqSocket::connect() {
     zmq_setsockopt(m_socket, ZMQ_SUBSCRIBE, "", 0);
 }
 
-void ZmqSocket::disconnect() {
-    zmq_close(m_socket);
-    zmq_ctx_destroy(m_context);
-    m_socket = nullptr;
-    m_context = nullptr;
-}
+size_t ZmqSocketReceiver::receive(ZmqHeader &header, std::byte *data, bool serialized_header) {
 
-ZmqSocket::~ZmqSocket() {
-    if (m_socket)
-        disconnect();
-    delete[] m_header_buffer;
-}
+    size_t data_bytes_received{};
 
-void ZmqSocket::set_zmq_hwm(int hwm) { m_zmq_hwm = hwm; }
+    if (serialized_header)
+        throw std::runtime_error("Not implemented");
 
-void ZmqSocket::set_timeout_ms(int n) { m_timeout_ms = n; }
-
-int ZmqSocket::receive(zmqHeader &header, std::byte *data) {
+    size_t header_bytes_received = zmq_recv(m_socket, m_header_buffer, m_max_header_size, 0);
 
     // receive header
-    int header_bytes_received = zmq_recv(m_socket, m_header_buffer, m_max_header_size, 0);
     m_header_buffer[header_bytes_received] = '\0'; // make sure we zero terminate
     if (header_bytes_received < 0) {
         fmt::print("Error receiving header: {}\n", strerror(errno));
         return -1;
     }
-    fmt::print("Bytes: {}, Header: {}\n", header_bytes_received, m_header_buffer);
+    aare::logger::debug("Bytes: ", header_bytes_received, ", Header: ", m_header_buffer);
 
-    // decode header
-    if (!decode_header(header)) {
-        fmt::print("Error decoding header\n");
+    // parse header
+    try {
+        std::string header_str(m_header_buffer);
+        header.from_string(header_str);
+    } catch (const simdjson::simdjson_error &e) {
+        aare::logger::error(LOCATION + "Error parsing header: ", e.what());
         return -1;
     }
 
@@ -67,16 +62,13 @@ int ZmqSocket::receive(zmqHeader &header, std::byte *data) {
     if (!more) {
         return 0; // no data following header
     } else {
-        int data_bytes_received = zmq_recv(m_socket, data, 1024 * 1024 * 2, 0); // TODO! configurable size!!!!
+
+        data_bytes_received = zmq_recv(m_socket, data, header.imageSize, 0); // TODO! configurable size!!!!
         if (data_bytes_received == -1)
             throw std::runtime_error("Got half of a multipart msg!!!");
+        aare::logger::debug("Bytes: ", data_bytes_received);
     }
-    return 1;
-}
-
-bool ZmqSocket::decode_header(zmqHeader &h) {
-    // TODO: implement
-    return true;
+    return data_bytes_received + header_bytes_received;
 }
 
 } // namespace aare
diff --git a/network_io/src/ZmqSocketSender.cpp b/network_io/src/ZmqSocketSender.cpp
new file mode 100644
index 0000000..ba296c6
--- /dev/null
+++ b/network_io/src/ZmqSocketSender.cpp
@@ -0,0 +1,32 @@
+#include "aare/ZmqSocketSender.hpp"
+
+#include <cassert>
+#include <zmq.h>
+
+namespace aare {
+ZmqSocketSender::ZmqSocketSender(const std::string &endpoint) { m_endpoint = endpoint; }
+
+void ZmqSocketSender::bind() {
+    m_context = zmq_ctx_new();
+    m_socket = zmq_socket(m_context, ZMQ_PUB);
+    size_t rc = zmq_bind(m_socket, m_endpoint.c_str());
+    assert(rc == 0);
+}
+
+size_t ZmqSocketSender::send(ZmqHeader &header, const std::byte *data, size_t size, bool serialize_header) {
+    size_t rc;
+    if (serialize_header) {
+        rc = zmq_send(m_socket, &header, sizeof(ZmqHeader), ZMQ_SNDMORE);
+        assert(rc == sizeof(ZmqHeader));
+    } else {
+        std::string header_str = header.to_string();
+        rc = zmq_send(m_socket, header_str.c_str(), header_str.size(), ZMQ_SNDMORE);
+        assert(rc == header_str.size());
+    }
+
+    size_t rc2 = zmq_send(m_socket, data, size, 0);
+    assert(rc2 == size);
+    return rc + rc2;
+}
+
+} // namespace aare
\ No newline at end of file
diff --git a/network_io/test/ZmqHeader.test.cpp b/network_io/test/ZmqHeader.test.cpp
new file mode 100644
index 0000000..787dfb6
--- /dev/null
+++ b/network_io/test/ZmqHeader.test.cpp
@@ -0,0 +1,80 @@
+#include "aare/ZmqHeader.hpp"
+#include "aare/utils/logger.hpp"
+#include <catch2/catch_test_macros.hpp>
+
+using namespace aare;
+TEST_CASE("Test ZmqHeader") {
+    ZmqHeader header;
+    header.npixelsx = 10;
+    header.npixelsy = 15;
+    header.data = 1;
+    header.jsonversion = 2;
+    header.dynamicRange = 32;
+    header.fileIndex = 4;
+    header.ndetx = 5;
+    header.ndety = 6;
+    header.imageSize = 4800;
+    header.acqIndex = 8;
+    header.frameIndex = 9;
+    header.progress = 0.1;
+    header.fname = "test";
+    header.frameNumber = 11;
+    header.expLength = 12;
+    header.packetNumber = 13;
+    header.detSpec1 = 14;
+    header.timestamp = 15;
+    header.modId = 16;
+    header.row = 17;
+    header.column = 18;
+    header.detSpec2 = 19;
+    header.detSpec3 = 20;
+    header.detSpec4 = 21;
+    header.detType = 22;
+    header.version = 23;
+    header.flipRows = 24;
+    header.quad = 25;
+    header.completeImage = 1;
+    header.addJsonHeader = {{"key1", "value1"}, {"key2", "value2"}};
+    header.rx_roi = {27, 28, 29, 30};
+
+    std::string json_header = "{"
+                              "\"data\": 1, "
+                              "\"jsonversion\": 2, "
+                              "\"dynamicRange\": 32, "
+                              "\"fileIndex\": 4, "
+                              "\"ndetx\": 5, "
+                              "\"ndety\": 6, "
+                              "\"npixelsx\": 10, "
+                              "\"npixelsy\": 15, "
+                              "\"imageSize\": 4800, "
+                              "\"acqIndex\": 8, "
+                              "\"frameIndex\": 9, "
+                              "\"progress\": 0.100000, "
+                              "\"fname\": \"test\", "
+                              "\"frameNumber\": 11, "
+                              "\"expLength\": 12, "
+                              "\"packetNumber\": 13, "
+                              "\"detSpec1\": 14, "
+                              "\"timestamp\": 15, "
+                              "\"modId\": 16, "
+                              "\"row\": 17, "
+                              "\"column\": 18, "
+                              "\"detSpec2\": 19, "
+                              "\"detSpec3\": 20, "
+                              "\"detSpec4\": 21, "
+                              "\"detType\": 22, "
+                              "\"version\": 23, "
+                              "\"flipRows\": 24, "
+                              "\"quad\": 25, "
+                              "\"completeImage\": 1, "
+                              "\"addJsonHeader\": {\"key1\": \"value1\", \"key2\": \"value2\"}, "
+                              "\"rx_roi\": [27, 28, 29, 30]"
+                              "}";
+
+    SECTION("Test converting ZmqHeader to json string") { REQUIRE(header.to_string() == json_header); }
+    SECTION("Test converting json string to ZmqHeader") {
+        ZmqHeader header2;
+        header2.from_string(json_header);
+        REQUIRE(header2 == header);
+    }
+}
diff --git a/utils/include/aare/utils/logger.hpp b/utils/include/aare/utils/logger.hpp
index ec7d05d..87928bf 100644
--- a/utils/include/aare/utils/logger.hpp
+++ b/utils/include/aare/utils/logger.hpp
@@ -2,6 +2,7 @@
 #include <filesystem>
 #include <fstream>
 #include <iostream>
+#include <map>
 #include <vector>
 
 #define LOCATION std::string(__FILE__) + std::string(":") + std::to_string(__LINE__) + ":" + std::string(__func__) + ":"
@@ -20,6 +21,30 @@ template <typename T> std::ostream &operator<<(std::ostream &out, const std::vec
     return out;
 }
 
+// operator overload for std::array
+template <typename T, size_t N> std::ostream &operator<<(std::ostream &out, const std::array<T, N> &v) {
+    out << "[";
+    size_t last = N - 1;
+    for (size_t i = 0; i < N; ++i) {
+        out << v[i];
+        if (i != last)
+            out << ", ";
+    }
+    out << "]";
+    return out;
+}
+// operator overlaod for std::map
+template <typename K, typename V> std::ostream &operator<<(std::ostream &out, const std::map<K, V> &v) {
+    out << "{";
+    size_t i = 0;
+    for (auto &kv : v) {
+        out << kv.first << ": " << kv.second << ((++i != v.size()) ? ", " : "");
+    }
+
+    out << "}";
+    return out;
+}
+
 namespace aare {
 
 namespace logger {