diff --git a/Cargo.lock b/Cargo.lock
index 605a485..26c7a85 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -212,6 +212,8 @@ dependencies = [
  "home",
  "log",
  "rusqlite",
+ "serde",
+ "serde_json",
  "simple_logger",
 ]
 
@@ -298,11 +300,42 @@ dependencies = [
  "smallvec",
 ]
 
+[[package]]
+name = "ryu"
+version = "1.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4501abdff3ae82a1c1b477a17252eb69cee9e66eb915c1abaa4f44d873df9f09"
+
 [[package]]
 name = "serde"
 version = "1.0.147"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d193d69bae983fc11a79df82342761dfbf28a99fc8d203dca4c3c1b590948965"
+dependencies = [
+ "serde_derive",
+]
+
+[[package]]
+name = "serde_derive"
+version = "1.0.147"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4f1d362ca8fc9c3e3a7484440752472d68a6caa98f1ab81d99b5dfe517cec852"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "serde_json"
+version = "1.0.89"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "020ff22c755c2ed3f8cf162dbb41a7268d934702f3ed3631656ea597e08fc3db"
+dependencies = [
+ "itoa",
+ "ryu",
+ "serde",
+]
 
 [[package]]
 name = "simple_logger"
diff --git a/Cargo.toml b/Cargo.toml
index 41665f7..5239c9b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,8 +7,10 @@ edition = "2021"
 
 [dependencies]
 rusqlite = { version = "0.28.0", features = ["bundled"] }
+serde = { version = "1.0", features = ["derive"] }
 clap = { version = "4.0.26", features = ["derive"] }
 clap-verbosity-flag = "2.0.0"
 simple_logger = "4.0.0"
 log = "0.4.17"
-home = "0.5.4"
\ No newline at end of file
+home = "0.5.4"
+serde_json = "1.0"
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
index bc97f23..464c6bd 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,15 +1,38 @@
-mod migration;
-mod users;
-
 use std::any::Any;
-use clap::{Command, Arg, ArgAction, ArgMatches, value_parser};
-use log::{debug, info};
-use simple_logger::SimpleLogger;
 use std::path::PathBuf;
-use rusqlite::{Connection};
+
+use clap::{Arg, ArgAction, ArgMatches, Command, value_parser};
+use serde::{Serialize};
+
+use log::{debug, error, info};
+use rusqlite::Connection;
+use simple_logger::SimpleLogger;
 
 use crate::migration::migrate;
 
+mod migration;
+mod users;
+
+#[derive(Debug, Serialize)]
+struct Output<T> {
+    status: String,
+    result: T,
+}
+
+impl<T> Output<T> {
+    fn success(shit: T) -> Output<T> {
+        return Output{status: "success".to_string(), result: shit};
+    }
+
+}
+
+trait CommandLineUserLogic {
+    fn create_user(&mut self, conn: &Connection, name: &String, public_key: &String);
+
+    fn list_user(&mut self, conn: &Connection);
+
+    // fn list_securities(&mut self, conn: &Connection);
+}
 
 fn verbosity_arg() -> Arg {
     return Arg::new("verbosity")
@@ -18,7 +41,7 @@ fn verbosity_arg() -> Arg {
         .default_value("0");
 }
 
-fn get_verbosity(m: & ArgMatches) -> log::LevelFilter {
+fn get_verbosity(m: &ArgMatches) -> log::LevelFilter {
     match m.get_one::<u8>("verbosity") {
         None => log::LevelFilter::Error,
         Some(1) => log::LevelFilter::Warn,
@@ -41,10 +64,100 @@ fn get_db_path(m: & ArgMatches) -> & PathBuf{
     return m.get_one::<PathBuf>("db-path").unwrap();
 }
 
+fn new_user_command_line_parser() -> Command {
+    return Command::new("new")
+        .long_flag("new")
+        .about("Create new user.")
+        .arg(Arg::new("name").long("name").help("name of new user.").action(ArgAction::Set))
+        .arg(Arg::new("public_key").long("public-key").help("public key of users.").action(ArgAction::Set));
+}
+
+fn ls_user_command_line_parser() -> Command {
+    return Command::new("ls")
+        .long_flag("ls")
+        .about("List all users.");
+}
+
+fn user_command_line_parser() -> Command {
+    return Command::new("users")
+        .subcommand(new_user_command_line_parser())
+        .subcommand(ls_user_command_line_parser());
+}
+
+fn command_line_parser() -> Command {
+    return Command::new("prog")
+        .arg(verbosity_arg())
+        .arg(db_path_arg())
+        .subcommand(user_command_line_parser());
+}
+
+fn process_new_user_command_line(conn: &Connection, m: &ArgMatches, logic: &mut dyn CommandLineUserLogic) {
+    debug!("Processing new user command line {:?}.", m);
+    let name = m.get_one::<String>("name").unwrap();
+    let pk = m.get_one::<String>("public_key").unwrap();
+    logic.create_user(conn, name, pk);
+}
+
+fn process_list_user_command_line(conn: &Connection, m: &ArgMatches, logic: &mut dyn CommandLineUserLogic) {
+    debug!("Processing list users command line {:?}.", m);
+    logic.list_user(conn);
+}
+
+fn process_user_command_line(conn: &Connection, m: &ArgMatches, logic: &mut dyn CommandLineUserLogic) {
+    debug!("Processing user command line {:?}.", m);
+    match m.subcommand() {
+        Some(("new", new_user_match)) => {
+            process_new_user_command_line(conn, new_user_match, logic);
+        }
+        Some(("ls", list_user_match)) => {
+            process_list_user_command_line(conn, list_user_match, logic);
+        }
+        _ => unreachable!(),
+    }
+}
+
+fn process_command_line(conn: &Connection, m: &ArgMatches, logic: &mut dyn CommandLineUserLogic) {
+    debug!("Processing command line {:?}.", m);
+    match m.subcommand() {
+        Some(("users", user_match)) => {
+            process_user_command_line(conn, user_match, logic);
+        }
+        _ => {
+            println!("Received unparsable command. {:?}", m.subcommand());
+            unreachable!();
+        },
+    }
+}
+
 #[cfg(test)]
 mod test {
     use super::*;
 
+    struct TestCommandLineLogic {
+        list_user_count: usize,
+        create_user_count: usize,
+
+    }
+
+    impl TestCommandLineLogic {
+        fn new() -> TestCommandLineLogic {
+            return TestCommandLineLogic {
+                list_user_count: 0,
+                create_user_count: 0,
+            };
+        }
+    }
+
+    impl CommandLineUserLogic for TestCommandLineLogic {
+        fn create_user(&mut self, conn: &Connection, name: &String, public_key: &String) {
+            self.create_user_count += 1;
+        }
+
+        fn list_user(&mut self, conn: &Connection) {
+            self.list_user_count += 1;
+        }
+    }
+
     #[test]
     fn verbosity() {
         {
@@ -67,7 +180,7 @@ mod test {
             let cmd = Command::new("test").arg(db_path_arg());
             let m = cmd.get_matches_from(vec!["test", "--db-path", "/foo/bar"]);
             let expt = PathBuf::from("/foo/bar");
-            assert_eq!(get_db_path(&m), & expt);
+            assert_eq!(get_db_path(&m), &expt);
         }
 
         {
@@ -76,78 +189,70 @@ mod test {
             let expt = PathBuf::from("ledger.sqlite");
             assert_eq!(get_db_path(&m), &expt);
         }
+    }
 
+    #[test]
+    fn create_user() {
+        let cmd = command_line_parser();
+        let m = cmd.get_matches_from(vec!["test", "users", "new", "--name", "paul", "--public-key", "123abc"]);
+        let mut logic = TestCommandLineLogic::new();
+        let conn = Connection::open_in_memory().unwrap();
+        process_command_line(&conn, &m, &mut logic);
+        assert_eq!(logic.create_user_count, 1);
+    }
+
+    #[test]
+    fn list_users() {
+        let cmd = command_line_parser();
+        let m = cmd.get_matches_from(vec!["test", "users", "ls"]);
+        let mut logic = TestCommandLineLogic::new();
+        let conn = Connection::open_in_memory().unwrap();
+        process_command_line(&conn, &m, &mut logic);
+        assert_eq!(logic.list_user_count, 1);
     }
 }
 
-fn new_user_command_line_parser() -> Command {
-    return Command::new("new")
-        .long_flag("new")
-        .about("Create new user.")
-        .arg(Arg::new("name").help("name of new user.").action(ArgAction::Set));
-}
+struct ProCommandLineLogic {}
 
-fn ls_user_command_line_parser() -> Command {
-    return Command::new("list")
-        .long_flag("ls")
-        .about("List all users.");
-}
-
-fn user_command_line_parser() -> Command {
-    return Command::new("users")
-        .subcommand(new_user_command_line_parser())
-        .subcommand(ls_user_command_line_parser());
-}
-
-
-fn command_line_parser() -> Command {
-    return Command::new("prog")
-        .arg(verbosity_arg())
-        .arg(db_path_arg())
-        .subcommand(user_command_line_parser());
-}
-
-fn process_new_user_command_line(conn: &Connection, m: &ArgMatches){
-    debug!("Processing new user command line {:?}.", m);
-
-}
-
-fn process_list_user_command_line(conn: &Connection, m: &ArgMatches){
-    debug!("Processing list users command line {:?}.", m);
-}
-
-fn process_user_command_line(conn: &Connection, m: &ArgMatches){
-    debug!("Processing user command line {:?}.", m);
-    match m.subcommand() {
-        Some(("new", new_user_match)) => {
-            process_new_user_command_line(conn, new_user_match);
-        }
-        Some(("list", list_user_match)) => {
-            process_list_user_command_line(conn, list_user_match);
-        }
-        _ => unreachable!(),
-    }
-
-
-}
-
-fn process_command_line(conn: & Connection, m: & ArgMatches) {
-    debug!("Processing command line {:?}.", m);
-    match m.subcommand() {
-        Some(("users", user_match)) => {
-            process_user_command_line(conn, user_match);
-        }
-        _ => unreachable!(),
+impl ProCommandLineLogic {
+    fn new() -> ProCommandLineLogic {
+        return ProCommandLineLogic {};
     }
 }
 
-fn get_connection(m: & ArgMatches) -> Connection {
+impl CommandLineUserLogic for ProCommandLineLogic {
+    fn create_user(&mut self, conn: &Connection, name: &String, public_key: &String) {
+        users::create_user(conn, name, public_key);
+    }
+
+    fn list_user(&mut self, conn: &Connection) {
+        let users = users::list_users(conn);
+        match users {
+            Ok(u) => {
+                let r: Vec<& users::User> = u.iter()
+                    .filter(|& x| x.is_ok())
+                    .map(| x| x.as_ref().unwrap())
+                    .collect();
+
+                let out = Output::success(r);
+
+                println!("{}", serde_json::to_string(& out).unwrap());
+            }
+            Err(e) => {
+                println!("{:?}", e);
+            }
+        }
+    }
+}
+
+
+fn get_connection(m: &ArgMatches) -> Connection {
     let path = get_db_path(&m);
     info!("Sqlite database location is {:?}.", path);
     return Connection::open(path).unwrap();
 }
 
-fn set_logger(m: & ArgMatches) {
+fn set_logger(m: &ArgMatches) {
     SimpleLogger::new().with_level(get_verbosity(&m)).init().unwrap();
 }
 
@@ -155,8 +260,9 @@ fn main() {
     let command = command_line_parser();
     let m = command.get_matches();
 
-    set_logger(& m);
-    let conn = get_connection(& m);
+    set_logger(&m);
+    let conn = get_connection(&m);
     migrate(&conn);
-    process_command_line(& conn, & m);
+    let mut logic = ProCommandLineLogic::new();
+    process_command_line(&conn, &m, &mut logic);
 }
\ No newline at end of file
diff --git a/src/migration.rs b/src/migration.rs
index 419369f..bfc133c 100644
--- a/src/migration.rs
+++ b/src/migration.rs
@@ -5,7 +5,7 @@ const MIGRATION_SCRIPT: &str = "
 CREATE TABLE IF NOT EXISTS users (
     id INTEGER PRIMARY KEY AUTOINCREMENT,
     name TEXT NOT NULL,
-    key TEXT NOT NULL
+    public_key TEXT NOT NULL
 );
 
 CREATE TABLE IF NOT EXISTS security_types (
diff --git a/src/users.rs b/src/users.rs
index a52e9ef..5df85e8 100644
--- a/src/users.rs
+++ b/src/users.rs
@@ -1,5 +1,28 @@
-use rusqlite::Connection;
+use rusqlite::{Connection, Result};
+use serde::{Serialize};
 
-fn create_user(conn: & Connection){
 
+#[derive(Debug, Serialize)]
+pub struct User {
+    id: i32,
+    name: String,
+    public_key: String,
+}
+
+pub fn create_user(conn: & Connection, name: &String, public_key: &String){
+    conn.execute("INSERT INTO users (name, public_key) VALUES (?1, ?2)",
+                 (name, public_key)).unwrap();
+}
+
+pub fn list_users(conn: & Connection) -> Result<Vec<Result<User>>>{
+
+    let mut stmt = conn.prepare("SELECT id, name, public_key FROM users")?;
+    let ret: Vec<Result<User>> = stmt.query_map([], |row| {
+        Ok(User {
+            id: row.get(0)?,
+            name: row.get(1)?,
+            public_key: row.get(2)?,
+        })
+    }).unwrap().collect();
+    return Ok(ret);
 }
\ No newline at end of file