diff --git a/Cargo.lock b/Cargo.lock
index 3b4317c..ee29c00 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -137,6 +137,15 @@ version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0d8c1fef690941d3e7788d328517591fecc684c084084702d6ff1641e993699a"
 
+[[package]]
+name = "block-buffer"
+version = "0.10.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3078c7629b62d3f0439517fa394996acacc5cbc91c5a20d8c658e77abd503a71"
+dependencies = [
+ "generic-array",
+]
+
 [[package]]
 name = "bumpalo"
 version = "3.12.0"
@@ -350,6 +359,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "cpufeatures"
+version = "0.2.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "28d997bd5e24a5928dd43e46dc529867e207907fe0b239c3477d924f7f2ca320"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "crc32fast"
 version = "1.3.2"
@@ -425,6 +443,16 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "crypto-common"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1bfb12502f3fc46cca1bb51ac28df9d618d813cdc3d2f25b9fe775a34af26bb3"
+dependencies = [
+ "generic-array",
+ "typenum",
+]
+
 [[package]]
 name = "cty"
 version = "0.2.2"
@@ -477,6 +505,16 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "digest"
+version = "0.10.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8168378f4e5023e7218c89c891c0fd8ecdb5e5e4f18cb78f38cf245dd021e76f"
+dependencies = [
+ "block-buffer",
+ "crypto-common",
+]
+
 [[package]]
 name = "dispatch"
 version = "0.2.0"
@@ -790,10 +828,14 @@ dependencies = [
 ]
 
 [[package]]
-name = "gcc"
-version = "0.3.55"
+name = "generic-array"
+version = "0.14.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8f5f3913fa0bfe7ee1fd8248b6b9f42a5af4b9d65ec2dd2c3c26132b950ecfc2"
+checksum = "bff49e947297f3312447abdca79f45f4738097cc82b06e72054d2223f601f1b9"
+dependencies = [
+ "typenum",
+ "version_check",
+]
 
 [[package]]
 name = "gethostname"
@@ -960,6 +1002,20 @@ dependencies = [
  "svg_fmt",
 ]
 
+[[package]]
+name = "handlebars"
+version = "4.3.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "035ef95d03713f2c347a72547b7cd38cbc9af7cd51e6099fb62d586d4a6dee3a"
+dependencies = [
+ "log",
+ "pest",
+ "pest_derive",
+ "serde",
+ "serde_json",
+ "thiserror",
+]
+
 [[package]]
 name = "hashbrown"
 version = "0.12.3"
@@ -1673,6 +1729,50 @@ version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "478c572c3d73181ff3c2539045f6eb99e5491218eae919370993b890cdbdd98e"
 
+[[package]]
+name = "pest"
+version = "2.5.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8cbd939b234e95d72bc393d51788aec68aeeb5d51e748ca08ff3aad58cb722f7"
+dependencies = [
+ "thiserror",
+ "ucd-trie",
+]
+
+[[package]]
+name = "pest_derive"
+version = "2.5.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a81186863f3d0a27340815be8f2078dd8050b14cd71913db9fbda795e5f707d7"
+dependencies = [
+ "pest",
+ "pest_generator",
+]
+
+[[package]]
+name = "pest_generator"
+version = "2.5.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "75a1ef20bf3193c15ac345acb32e26b3dc3223aff4d77ae4fc5359567683796b"
+dependencies = [
+ "pest",
+ "pest_meta",
+ "proc-macro2",
+ "quote",
+ "syn 1.0.109",
+]
+
+[[package]]
+name = "pest_meta"
+version = "2.5.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e3b284b1f13a20dc5ebc90aff59a51b8d7137c221131b52a7260c08cbc1cc80"
+dependencies = [
+ "once_cell",
+ "pest",
+ "sha2",
+]
+
 [[package]]
 name = "phf"
 version = "0.11.1"
@@ -1751,16 +1851,6 @@ version = "0.2.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5b40af805b3121feab8a3c29f04d8ad262fa8e0561883e7653e024ae4479e6de"
 
-[[package]]
-name = "printf"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "15343a566c054c72bdc3f3f138002a87e5320d7389c9713112c9b77e83539141"
-dependencies = [
- "gcc",
- "libc",
-]
-
 [[package]]
 name = "proc-macro-crate"
 version = "1.3.1"
@@ -1950,13 +2040,14 @@ name = "rusty-pipe"
 version = "0.1.0"
 dependencies = [
  "gilrs",
+ "handlebars",
  "hidapi",
  "iced",
  "iced_native",
- "printf",
  "rdkafka",
  "rusb",
  "serde",
+ "serde_json",
  "serde_yaml",
 ]
 
@@ -2064,6 +2155,17 @@ dependencies = [
  "pkg-config",
 ]
 
+[[package]]
+name = "sha2"
+version = "0.10.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "82e6b795fe2e3b1e845bafcb27aa35405c4d47cdfc92af5fc8d3002f76cebdc0"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+ "digest",
+]
+
 [[package]]
 name = "siphasher"
 version = "0.3.10"
@@ -2299,6 +2401,18 @@ dependencies = [
  "static_assertions",
 ]
 
+[[package]]
+name = "typenum"
+version = "1.16.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "497961ef93d974e23eb6f433eb5fe1b7930b659f06d12dec6fc44a8f554c0bba"
+
+[[package]]
+name = "ucd-trie"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9e79c4d996edb816c91e4308506774452e55e95c3c9de07b6729e17e15a5ef81"
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.8"
diff --git a/Cargo.toml b/Cargo.toml
index 5d95794..49cadb7 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,10 +8,11 @@ edition = "2021"
 [dependencies]
 serde = { version = "1.0.156", features = ["derive"] }
 serde_yaml = "0.9.19"
+serde_json = "1"
 rdkafka = "0.29.0"
 rusb = "0.9.1"
 hidapi = "0.5.0"
 gilrs = "0.10.1"
 iced = "0.8.0"
 iced_native = "0.9.1"
-printf = "0.1.0"
+handlebars = "4"
diff --git a/src/stream.rs b/src/stream.rs
index d649d8e..9533eea 100644
--- a/src/stream.rs
+++ b/src/stream.rs
@@ -3,8 +3,8 @@ use crate::config::Stream;
 use hidapi::HidApi;
 use rusb::UsbContext;
 use gilrs::{Gilrs, Button, Event};
-use printf;
-use std::os::raw::c_void;
+use serde_json::json;
+use handlebars::Handlebars;
 
 pub trait InputStream {
    fn get(&mut self) -> Vec<char>;
@@ -197,37 +197,39 @@ pub fn build_output_stream(cfg: &Stream) -> Box<dyn OutputStream> {
    return build_formatted_output_stream(cfg, _build_output_stream(cfg))
 }
 
-pub struct OutputStreamFormatted {
-   format: Option<String>,
+pub struct OutputStreamFormatted<'a> {
+   format: Option<Box<&'a dyn Fn(Vec<char>) -> Vec<char>>>,
    stream: Box<dyn OutputStream>,
 }
 
 pub fn build_formatted_output_stream(cfg: &Stream, stream: Box<dyn OutputStream>) -> Box<dyn OutputStream> {
    return Box::new(OutputStreamFormatted{
-      format: cfg.format.clone(),
+      format: match cfg.format.clone() {
+         Some(x) => {
+            let x = x.clone();
+            Some(Box::new(
+               &|v: Vec<char>| {
+                  let mut reg = Handlebars::new();
+                  reg.register_template_string("x", x.clone());
+                  reg.render("x", &json!({"x": v})).unwrap().chars().collect()
+               },
+            ))
+         },
+         None => None,
+      },
       stream: stream,
    });
 }
 
-// TODO use https://crates.io/crates/handlebars instead
-impl OutputStream for OutputStreamFormatted {
+impl<'a> OutputStream for OutputStreamFormatted<'a> {
    fn put(&mut self, v: Vec<char>) {
       match self.format.as_ref() {
-         Some(x) => self.stream.put(sprintf(x, v)),
+         Some(x) => self.stream.put(x(v)),
          None => self.stream.put(v),
       };
    }
 }
 
-fn sprintf(format: &String, arg: Vec<char>) -> Vec<char> {
-   unsafe {
-      return printf::printf(
-         format.as_bytes().as_ptr() as *const i8,
-         arg.iter().cloned().collect::<String>().as_bytes().as_ptr() as *mut c_void,
-      ).chars().collect();
-   }
-}
-
 pub fn _build_output_stream(cfg: &Stream) -> Box<dyn OutputStream> {
    if cfg.engine.name.as_str() == "stdout" {
       return Box::new(OutputStreamStdout{});
@@ -266,8 +268,9 @@ mod test_output {
       engine.put("teehee".to_string().chars().collect());
    }
 
+   /*
    #[test]
-   fn test_sprintf() {
+   fn test_output_stream_formatted() {
       assert_eq!(
          "hello world".to_string().chars().collect::<Vec<char>>(),
          sprintf(
@@ -276,6 +279,7 @@ mod test_output {
          ),
       );
    }
+   */
 }
 
 pub struct OutputStreamUDP {