diff --git a/demboyz/base/jsonfile.cpp b/demboyz/base/jsonfile.cpp
new file mode 100644
index 0000000..a7a4b4b
--- /dev/null
+++ b/demboyz/base/jsonfile.cpp
@@ -0,0 +1,154 @@
+
+#include "jsonfile.h"
+#include "b64/encode.h"
+#include <cstdlib>
+
+namespace base
+{
+    JsonWriterFile::JsonWriterFile(FILE* fp, char* buffer, std::size_t length):
+        m_fileStream(fp, buffer, length),
+        m_writer(m_fileStream),
+        m_fp(fp)
+    {
+    }
+
+    FILE* JsonWriterFile::GetFp() const
+    {
+        return m_fp;
+    }
+
+    void JsonWriterFile::Flush()
+    {
+        m_fileStream.Flush();
+    }
+
+    bool JsonWriterFile::IsComplete() const
+    {
+        return m_writer.IsComplete();
+    }
+
+    void JsonWriterFile::StartObject(const char* name /*= nullptr*/)
+    {
+        auto& writer = m_writer;
+        if (name)
+        {
+            writer.String(name);
+        }
+        writer.StartObject();
+    }
+
+    void JsonWriterFile::EndObject()
+    {
+        m_writer.EndObject();
+    }
+
+    void JsonWriterFile::StartArray(const char* name /*= nullptr*/)
+    {
+        auto& writer = m_writer;
+        if (name)
+        {
+            writer.String(name);
+        }
+        writer.StartArray();
+    }
+
+    void JsonWriterFile::EndArray()
+    {
+        m_writer.EndArray();
+    }
+
+    void JsonWriterFile::WriteBool(const char* name, bool value)
+    {
+        auto& writer = m_writer;
+        writer.String(name);
+        writer.Bool(value);
+    }
+
+    void JsonWriterFile::WriteInt32(const char* name, std::int32_t value)
+    {
+        auto& writer = m_writer;
+        writer.String(name);
+        writer.Int(value);
+    }
+
+    void JsonWriterFile::WriteInt64(const char* name, std::int64_t value)
+    {
+        auto& writer = m_writer;
+        writer.String(name);
+        writer.Int64(value);
+    }
+
+    void JsonWriterFile::WriteUInt32(const char* name, std::uint32_t value)
+    {
+        auto& writer = m_writer;
+        writer.String(name);
+        writer.Uint(value);
+    }
+
+    void JsonWriterFile::WriteUint64(const char* name, std::uint64_t value)
+    {
+        auto& writer = m_writer;
+        writer.String(name);
+        writer.Uint64(value);
+    }
+
+    void JsonWriterFile::WriteString(const char* name, const char* value)
+    {
+        auto& writer = m_writer;
+        writer.String(name);
+        writer.String(value);
+    }
+
+    void JsonWriterFile::WriteString(const char* name, const char* value, std::int32_t length)
+    {
+        auto& writer = m_writer;
+        writer.String(name);
+        writer.String(value, length);
+    }
+
+    void JsonWriterFile::WriteFloat(const char* name, const double value)
+    {
+        auto& writer = m_writer;
+        writer.String(name);
+        writer.Double(value);
+    }
+
+    void JsonWriterFile::WriteBits(const char* name, const unsigned char* data, std::size_t numBits)
+    {
+        auto& writer = m_writer;
+        writer.String(name);
+
+        base64::base64_encodestate state;
+        base64::base64_init_encodestate(&state);
+        state.flags = base64::BASE64_ENC_NO_NEWLINE_TERM;
+
+        const std::size_t numBytes = ((numBits + 7) >> 3);
+        const int encodedLenMax = base64::base64_calc_buffer_length(numBytes, &state);
+
+        char* const encoded = (char*)calloc(encodedLenMax, 1);
+        char* encodedCurOut = encoded;
+
+        const std::size_t numTrailingBits = (numBits & 7);
+        if (numTrailingBits > 0)
+        {
+            const std::size_t numBytesWithoutBits = (numBits >> 3);
+            encodedCurOut += base64::base64_encode_block((const char*)data, numBytesWithoutBits, encodedCurOut, &state);
+            const char lastByteClean = data[numBytesWithoutBits] & ~(0xFF >> numTrailingBits);
+            encodedCurOut += base64::base64_encode_block(&lastByteClean, 1, encodedCurOut, &state);
+        }
+        else
+        {
+            encodedCurOut += base64::base64_encode_block((const char*)data, numBytes, encodedCurOut, &state);
+        }
+        encodedCurOut += base64::base64_encode_blockend(encodedCurOut, &state);
+
+        writer.String(encoded, encodedCurOut - encoded);
+        free(encoded);
+        return;
+    }
+
+    void JsonWriterFile::WriteBytes(const char* name, const unsigned char* data, std::size_t numBytes)
+    {
+        JsonWriterFile::WriteBits(name, data, numBytes * 8);
+    }
+}
diff --git a/demboyz/base/jsonfile.h b/demboyz/base/jsonfile.h
new file mode 100644
index 0000000..5164bd9
--- /dev/null
+++ b/demboyz/base/jsonfile.h
@@ -0,0 +1,45 @@
+
+#pragma once
+
+#include <rapidjson/filewritestream.h>
+#include <rapidjson/writer.h>
+#include <cstdint>
+#include <cstdio>
+#include <cstddef>
+
+namespace base
+{
+    class JsonWriterFile
+    {
+    public:
+        JsonWriterFile(FILE* fp, char* buffer, std::size_t length);
+
+        FILE* GetFp() const;
+        void Flush();
+        bool IsComplete() const;
+
+        void StartObject(const char* name = nullptr);
+        void EndObject();
+
+        void StartArray(const char* name = nullptr);
+        void EndArray();
+
+        void WriteNull(const char* name);
+        void WriteBool(const char* name, bool value);
+        void WriteInt32(const char* name, std::int32_t value);
+        void WriteInt64(const char* name, std::int64_t value);
+        void WriteUInt32(const char* name, std::uint32_t value);
+        void WriteUint64(const char* name, std::uint64_t value);
+        void WriteString(const char* name, const char* value);
+        void WriteString(const char* name, const char* value, std::int32_t length);
+        void WriteFloat(const char* name, const double value);
+
+        void WriteBits(const char* name, const unsigned char* data, std::size_t numBits);
+        void WriteBytes(const char* name, const unsigned char* data, std::size_t numBytes);
+
+    private:
+        rapidjson::FileWriteStream m_fileStream;
+        rapidjson::Writer<rapidjson::FileWriteStream> m_writer;
+        FILE* m_fp;
+    };
+}