diff --git a/src/console_commands.cpp b/src/console_commands.cpp
index 233240f..48922f7 100644
--- a/src/console_commands.cpp
+++ b/src/console_commands.cpp
@@ -358,7 +358,7 @@ void ConsoleCommands::stdinReadCallback(uv_stream_t* stream, ssize_t nread, cons
 }
 
 
-void ConsoleCommands::process_input(std::string& command, char* data, uint32_t size)
+void ConsoleCommands::process_input(std::string& command, const char* data, uint32_t size)
 {
 	command.append(data, size);
 
diff --git a/src/console_commands.h b/src/console_commands.h
index e6d570e..77e8ba1 100644
--- a/src/console_commands.h
+++ b/src/console_commands.h
@@ -40,7 +40,7 @@ public:
 		size_t size() const override { return sizeof(ConsoleClient); }
 
 		bool on_connect() override { return true; };
-		bool on_read(char* data, uint32_t size) override { static_cast<ConsoleCommands*>(m_owner)->process_input(m_command, data, size); return true; };
+		bool on_read(const char* data, uint32_t size) override { static_cast<ConsoleCommands*>(m_owner)->process_input(m_command, data, size); return true; };
 
 		char m_consoleReadBuf[1024] = {};
 
@@ -66,7 +66,7 @@ private:
 	static void allocCallback(uv_handle_t* handle, size_t suggested_size, uv_buf_t* buf);
 	static void stdinReadCallback(uv_stream_t* stream, ssize_t nread, const uv_buf_t* buf);
 
-	void process_input(std::string& command, char* data, uint32_t size);
+	void process_input(std::string& command, const char* data, uint32_t size);
 };
 
 } // namespace p2pool
diff --git a/src/merge_mining_client_tari.cpp b/src/merge_mining_client_tari.cpp
index 144c766..f9aa533 100644
--- a/src/merge_mining_client_tari.cpp
+++ b/src/merge_mining_client_tari.cpp
@@ -574,7 +574,7 @@ bool MergeMiningClientTari::TariClient::on_connect()
 	return true;
 }
 
-bool MergeMiningClientTari::TariClient::on_read(char* data, uint32_t size)
+bool MergeMiningClientTari::TariClient::on_read(const char* data, uint32_t size)
 {
 	MergeMiningClientTari::TariServer* server = static_cast<MergeMiningClientTari::TariServer*>(m_owner);
 	if (!server) {
diff --git a/src/merge_mining_client_tari.h b/src/merge_mining_client_tari.h
index 0ce51c5..197181b 100644
--- a/src/merge_mining_client_tari.h
+++ b/src/merge_mining_client_tari.h
@@ -98,7 +98,7 @@ private:
 
 		void reset() override;
 		[[nodiscard]] bool on_connect() override;
-		[[nodiscard]] bool on_read(char* data, uint32_t size) override;
+		[[nodiscard]] bool on_read(const char* data, uint32_t size) override;
 
 		char m_buf[BUF_SIZE];
 		std::vector<uint8_t> m_pendingData;
diff --git a/src/p2p_server.cpp b/src/p2p_server.cpp
index ab3e0c7..fc836c0 100644
--- a/src/p2p_server.cpp
+++ b/src/p2p_server.cpp
@@ -1496,7 +1496,7 @@ bool P2PServer::P2PClient::on_connect()
 	return send_handshake_challenge();
 }
 
-bool P2PServer::P2PClient::on_read(char* data, uint32_t size)
+bool P2PServer::P2PClient::on_read(const char* data, uint32_t size)
 {
 	P2PServer* server = static_cast<P2PServer*>(m_owner);
 	if (!server) {
diff --git a/src/p2p_server.h b/src/p2p_server.h
index 7433414..ea5e91c 100644
--- a/src/p2p_server.h
+++ b/src/p2p_server.h
@@ -79,7 +79,7 @@ public:
 
 		void reset() override;
 		[[nodiscard]] bool on_connect() override;
-		[[nodiscard]] bool on_read(char* data, uint32_t size) override;
+		[[nodiscard]] bool on_read(const char* data, uint32_t size) override;
 		void on_read_failed(int err) override;
 		void on_disconnected() override;
 
diff --git a/src/stratum_server.cpp b/src/stratum_server.cpp
index 51c46ed..151e7c0 100644
--- a/src/stratum_server.cpp
+++ b/src/stratum_server.cpp
@@ -1171,7 +1171,7 @@ bool StratumServer::StratumClient::on_connect()
 	return true;
 }
 
-bool StratumServer::StratumClient::on_read(char* data, uint32_t size)
+bool StratumServer::StratumClient::on_read(const char* data, uint32_t size)
 {
 #ifdef WITH_TLS
 	if (!m_tlsChecked) {
@@ -1186,7 +1186,7 @@ bool StratumServer::StratumClient::on_read(char* data, uint32_t size)
 	}
 #endif
 
-	auto on_parse = [this](char* data, uint32_t size) {
+	auto on_parse = [this](const char* data, uint32_t size) {
 		if (static_cast<size_t>(m_stratumReadBufBytes) + size > STRATUM_BUF_SIZE) {
 			LOGWARN(4, "client " << static_cast<const char*>(m_addrString) << " sent too long Stratum message");
 			ban(DEFAULT_BAN_TIME);
diff --git a/src/stratum_server.h b/src/stratum_server.h
index 84257ef..bc0b8b2 100644
--- a/src/stratum_server.h
+++ b/src/stratum_server.h
@@ -47,7 +47,7 @@ public:
 
 		void reset() override;
 		[[nodiscard]] bool on_connect() override;
-		[[nodiscard]] bool on_read(char* data, uint32_t size) override;
+		[[nodiscard]] bool on_read(const char* data, uint32_t size) override;
 
 		[[nodiscard]] bool process_request(char* data, uint32_t size);
 		[[nodiscard]] bool process_login(rapidjson::Document& doc, uint32_t id);
diff --git a/src/tcp_server.cpp b/src/tcp_server.cpp
index 9d96cbd..a620057 100644
--- a/src/tcp_server.cpp
+++ b/src/tcp_server.cpp
@@ -1107,7 +1107,7 @@ void TCPServer::Client::on_read(uv_stream_t* stream, ssize_t nread, const uv_buf
 	}
 }
 
-bool TCPServer::Client::on_proxy_handshake(char* data, uint32_t size)
+bool TCPServer::Client::on_proxy_handshake(const char* data, uint32_t size)
 {
 	if ((data != m_readBuf + m_numRead) || (data + size > m_readBuf + m_readBufSize)) {
 		LOGERR(1, "peer " << static_cast<char*>(m_addrString) << " invalid data pointer or size in on_read()");
diff --git a/src/tcp_server.h b/src/tcp_server.h
index 262ed06..946f792 100644
--- a/src/tcp_server.h
+++ b/src/tcp_server.h
@@ -63,8 +63,8 @@ public:
 
 		virtual void reset();
 		[[nodiscard]] virtual bool on_connect() = 0;
-		[[nodiscard]] virtual bool on_read(char* data, uint32_t size) = 0;
-		[[nodiscard]] bool on_proxy_handshake(char* data, uint32_t size);
+		[[nodiscard]] virtual bool on_read(const char* data, uint32_t size) = 0;
+		[[nodiscard]] bool on_proxy_handshake(const char* data, uint32_t size);
 		virtual void on_read_failed(int /*err*/) {}
 		virtual void on_disconnected() {}
 
diff --git a/src/tls.cpp b/src/tls.cpp
index 5d4aa5e..47f42ed 100644
--- a/src/tls.cpp
+++ b/src/tls.cpp
@@ -217,7 +217,7 @@ bool ServerTls::init()
 	return true;
 }
 
-bool ServerTls::on_read_internal(char* data, uint32_t size, ReadCallback::Base&& read_callback, WriteCallback::Base&& write_callback)
+bool ServerTls::on_read_internal(const char* data, uint32_t size, ReadCallback::Base&& read_callback, WriteCallback::Base&& write_callback)
 {
 	SSL* ssl = m_ssl.get();
 	if (!ssl) {
diff --git a/src/tls.h b/src/tls.h
index e4387ac..10f9112 100644
--- a/src/tls.h
+++ b/src/tls.h
@@ -43,7 +43,7 @@ public:
 	[[nodiscard]] bool init();
 
 	template<typename T, typename U>
-	[[nodiscard]] FORCEINLINE bool on_read(char* data, uint32_t size, T&& read_callback, U&& write_callback)
+	[[nodiscard]] FORCEINLINE bool on_read(const char* data, uint32_t size, T&& read_callback, U&& write_callback)
 	{
 		return on_read_internal(data, size, ReadCallback::Derived<T>(std::move(read_callback)), WriteCallback::Derived<U>(std::move(write_callback)));
 	}
@@ -60,7 +60,7 @@ private:
 	typedef Callback<bool, char*, uint32_t> ReadCallback;
 	typedef Callback<bool, const uint8_t*, size_t> WriteCallback;
 
-	[[nodiscard]] bool on_read_internal(char* data, uint32_t size, ReadCallback::Base&& read_callback, WriteCallback::Base&& write_callback);
+	[[nodiscard]] bool on_read_internal(const char* data, uint32_t size, ReadCallback::Base&& read_callback, WriteCallback::Base&& write_callback);
 	[[nodiscard]] bool on_write_internal(const uint8_t* data, size_t size, WriteCallback::Base&& write_callback);
 
 private: