diff --git a/rpc/types/src/constants.rs b/rpc/types/src/constants.rs
new file mode 100644
index 0000000..451101f
--- /dev/null
+++ b/rpc/types/src/constants.rs
@@ -0,0 +1,56 @@
+//! TODO
+
+// From: <https://github.com/monero-project/monero/blob/cc73fe71162d564ffda8e549b79a350bca53c454/src/rpc/core_rpc_server_commands_defs.h#L83-L89>
+//
+// ```
+// When making *any* change here, bump minor
+// If the change is incompatible, then bump major and set minor to 0
+// This ensures CORE_RPC_VERSION always increases, that every change
+// has its own version, and that clients can just test major to see
+// whether they can talk to a given daemon without having to know in
+// advance which version they will stop working with
+// Don't go over 32767 for any of these
+// ```
+//
+// What this means for Cuprate: just follow `monerod`.
+
+//---------------------------------------------------------------------------------------------------- Import
+
+//---------------------------------------------------------------------------------------------------- Status
+/// <https://github.com/monero-project/monero/blob/cc73fe71162d564ffda8e549b79a350bca53c454/src/rpc/core_rpc_server_commands_defs.h#L78>
+pub const CORE_RPC_STATUS_OK: &str = "OK";
+
+/// <https://github.com/monero-project/monero/blob/cc73fe71162d564ffda8e549b79a350bca53c454/src/rpc/core_rpc_server_commands_defs.h#L79>
+pub const CORE_RPC_STATUS_BUSY: &str = "BUSY";
+
+/// <https://github.com/monero-project/monero/blob/cc73fe71162d564ffda8e549b79a350bca53c454/src/rpc/core_rpc_server_commands_defs.h#L80>
+pub const CORE_RPC_STATUS_NOT_MINING: &str = "NOT MINING";
+
+/// <https://github.com/monero-project/monero/blob/cc73fe71162d564ffda8e549b79a350bca53c454/src/rpc/core_rpc_server_commands_defs.h#L81>
+pub const CORE_RPC_STATUS_PAYMENT_REQUIRED: &str = "PAYMENT REQUIRED";
+
+//---------------------------------------------------------------------------------------------------- Versions
+/// RPC major version.
+///
+/// See: <https://github.com/monero-project/monero/blob/cc73fe71162d564ffda8e549b79a350bca53c454/src/rpc/core_rpc_server_commands_defs.h#L90>.
+pub const CORE_RPC_VERSION_MAJOR: u32 = 3;
+
+/// RPC miror version.
+///
+/// See: <https://github.com/monero-project/monero/blob/cc73fe71162d564ffda8e549b79a350bca53c454/src/rpc/core_rpc_server_commands_defs.h#L91>.
+pub const CORE_RPC_VERSION_MINOR: u32 = 14;
+
+/// RPC version.
+///
+/// See: <https://github.com/monero-project/monero/blob/cc73fe71162d564ffda8e549b79a350bca53c454/src/rpc/core_rpc_server_commands_defs.h#L92-L93>.
+///
+/// ```rust
+/// assert_eq!(cuprate_rpc_types::CORE_RPC_VERSION, 196_622);
+/// ```
+pub const CORE_RPC_VERSION: u32 = (CORE_RPC_VERSION_MAJOR << 16) | CORE_RPC_VERSION_MINOR;
+
+//---------------------------------------------------------------------------------------------------- Tests
+#[cfg(test)]
+mod test {
+    // use super::*;
+}
diff --git a/rpc/types/src/lib.rs b/rpc/types/src/lib.rs
index ec5f4c6..8cd8382 100644
--- a/rpc/types/src/lib.rs
+++ b/rpc/types/src/lib.rs
@@ -93,11 +93,19 @@
         clippy::too_many_lines
     )
 )]
+// TODO: remove me after finishing impl
+#![allow(dead_code)]
 
 //---------------------------------------------------------------------------------------------------- Use
+mod constants;
 mod macros;
 mod status;
 
+pub use constants::{
+    CORE_RPC_STATUS_BUSY, CORE_RPC_STATUS_NOT_MINING, CORE_RPC_STATUS_OK,
+    CORE_RPC_STATUS_PAYMENT_REQUIRED, CORE_RPC_VERSION, CORE_RPC_VERSION_MAJOR,
+    CORE_RPC_VERSION_MINOR,
+};
 pub use status::Status;
 
 pub mod bin;
diff --git a/rpc/types/src/status.rs b/rpc/types/src/status.rs
index fc19450..6730744 100644
--- a/rpc/types/src/status.rs
+++ b/rpc/types/src/status.rs
@@ -11,6 +11,9 @@ use strum::{
 // Do we need `strum`? Are there other types
 // (maybe outside of this crate) that will use it?
 
+// TODO:
+// These may be JSON-RPC 2.0 messages.
+
 //---------------------------------------------------------------------------------------------------- Status
 /// RPC response status.
 ///