diff --git a/Cargo.lock b/Cargo.lock
index f387f71..a6592b4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -118,6 +118,12 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "bumpalo"
+version = "3.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d32a994c2b3ca201d9b263612a374263f05e7adde37c4707f693dcd375076d1f"
+
 [[package]]
 name = "byteorder"
 version = "1.5.0"
@@ -195,6 +201,31 @@ version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5443807d6dff69373d433ab9ef5378ad8df50ca6298caf15de6e52e24aaf54d5"
 
+[[package]]
+name = "erased-serde"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "388979d208a049ffdfb22fa33b9c81942215b940910bccfe258caeb25d125cb3"
+dependencies = [
+ "serde",
+]
+
+[[package]]
+name = "femme"
+version = "2.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc04871e5ae3aa2952d552dae6b291b3099723bf779a8054281c1366a54613ef"
+dependencies = [
+ "cfg-if",
+ "js-sys",
+ "log",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "wasm-bindgen",
+ "web-sys",
+]
+
 [[package]]
 name = "fnv"
 version = "1.0.7"
@@ -450,6 +481,15 @@ version = "1.0.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b1a46d1a171d865aa5f83f92695765caa047a9b4cbae2cbf37dbd613a793fd4c"
 
+[[package]]
+name = "js-sys"
+version = "0.3.68"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "406cda4b368d531c842222cf9d2600a9a4acce8d29423695379c6868a143a9ee"
+dependencies = [
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "libc"
 version = "0.2.153"
@@ -477,6 +517,10 @@ name = "log"
 version = "0.4.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b5e6163cb8c49088c2c36f57875e58ccd8c87c7427f7fbd50ea6710b2f3f2e8f"
+dependencies = [
+ "serde",
+ "value-bag",
+]
 
 [[package]]
 name = "memchr"
@@ -744,6 +788,8 @@ name = "sandy"
 version = "0.1.0"
 dependencies = [
  "askama",
+ "femme",
+ "log",
  "rand",
  "serde",
  "serde_json",
@@ -784,6 +830,15 @@ dependencies = [
  "syn 2.0.49",
 ]
 
+[[package]]
+name = "serde_fmt"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e1d4ddca14104cd60529e8c7f7ba71a2c8acd8f7f5cfcdc2faf97eeb7c3010a4"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "serde_json"
 version = "1.0.113"
@@ -875,6 +930,84 @@ dependencies = [
  "warp",
 ]
 
+[[package]]
+name = "sval"
+version = "2.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "82a2386bea23a121e4e72450306b1dd01078b6399af11b93897bf84640a28a59"
+
+[[package]]
+name = "sval_buffer"
+version = "2.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b16c047898a0e19002005512243bc9ef1c1037aad7d03d6c594e234efec80795"
+dependencies = [
+ "sval",
+ "sval_ref",
+]
+
+[[package]]
+name = "sval_dynamic"
+version = "2.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a74fb116e2ecdcb280b0108aa2ee4434df50606c3208c47ac95432730eaac20c"
+dependencies = [
+ "sval",
+]
+
+[[package]]
+name = "sval_fmt"
+version = "2.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "10837b4f0feccef271b2b1c03784e08f6d0bb6d23272ec9e8c777bfadbb8f1b8"
+dependencies = [
+ "itoa",
+ "ryu",
+ "sval",
+]
+
+[[package]]
+name = "sval_json"
+version = "2.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "891f5ecdf34ce61a8ab2d10f9cfdc303347b0afec4dad6702757419d2d8312a9"
+dependencies = [
+ "itoa",
+ "ryu",
+ "sval",
+]
+
+[[package]]
+name = "sval_nested"
+version = "2.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "63fcffb4b79c531f38e3090788b64f3f4d54a180aacf02d69c42fa4e4bf284c3"
+dependencies = [
+ "sval",
+ "sval_buffer",
+ "sval_ref",
+]
+
+[[package]]
+name = "sval_ref"
+version = "2.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "af725f9c2aa7cec4ca9c47da2cc90920c4c82d3fa537094c66c77a5459f5809d"
+dependencies = [
+ "sval",
+]
+
+[[package]]
+name = "sval_serde"
+version = "2.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3d7589c649a03d21df40b9a926787d2c64937fa1dccec8d87c6cd82989a2e0a4"
+dependencies = [
+ "serde",
+ "sval",
+ "sval_nested",
+]
+
 [[package]]
 name = "syn"
 version = "1.0.109"
@@ -1109,6 +1242,42 @@ version = "0.7.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "09cc8ee72d2a9becf2f2febe0205bbed8fc6615b7cb429ad062dc7b7ddd036a9"
 
+[[package]]
+name = "value-bag"
+version = "1.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "126e423afe2dd9ac52142e7e9d5ce4135d7e13776c529d27fd6bc49f19e3280b"
+dependencies = [
+ "value-bag-serde1",
+ "value-bag-sval2",
+]
+
+[[package]]
+name = "value-bag-serde1"
+version = "1.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ede32f342edc46e84bd41fd394ce2192b553de11725dd83b6223150610c21b44"
+dependencies = [
+ "erased-serde",
+ "serde",
+ "serde_fmt",
+]
+
+[[package]]
+name = "value-bag-sval2"
+version = "1.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0024e44b25144c2f4d0ed35d39688e0090d57753e20fef38d08e0c1a40bdf23d"
+dependencies = [
+ "sval",
+ "sval_buffer",
+ "sval_dynamic",
+ "sval_fmt",
+ "sval_json",
+ "sval_ref",
+ "sval_serde",
+]
+
 [[package]]
 name = "version_check"
 version = "0.9.4"
@@ -1161,6 +1330,72 @@ version = "0.11.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9c8d87e72b64a3b4db28d11ce29237c246188f4f51057d65a7eab63b7987e423"
 
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.91"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1e124130aee3fb58c5bdd6b639a0509486b0338acaaae0c84a5124b0f588b7f"
+dependencies = [
+ "cfg-if",
+ "serde",
+ "serde_json",
+ "wasm-bindgen-macro",
+]
+
+[[package]]
+name = "wasm-bindgen-backend"
+version = "0.2.91"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c9e7e1900c352b609c8488ad12639a311045f40a35491fb69ba8c12f758af70b"
+dependencies = [
+ "bumpalo",
+ "log",
+ "once_cell",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.49",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.91"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b30af9e2d358182b5c7449424f017eba305ed32a7010509ede96cdc4696c46ed"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.91"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "642f325be6301eb8107a83d12a8ac6c1e1c54345a7ef1a9261962dfefda09e66"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.49",
+ "wasm-bindgen-backend",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.91"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4f186bd2dcf04330886ce82d6f33dd75a7bfcf69ecf5763b89fcde53b6ac9838"
+
+[[package]]
+name = "web-sys"
+version = "0.3.68"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96565907687f7aceb35bc5fc03770a8a0471d82e479f25832f54a0e3f4b28446"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.48.0"
diff --git a/Cargo.toml b/Cargo.toml
index 61a9f20..013ae4f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,8 @@ edition = "2021"
 
 [dependencies]
 askama = "0.12.1"
+femme = "2.2.1"
+log = "0.4.20"
 rand = "0.8.5"
 serde = { version = "1.0.196", features = ["derive"] }
 serde_json = "1.0.113"
diff --git a/src/executor.rs b/src/executor.rs
index cefbed1..18ea100 100644
--- a/src/executor.rs
+++ b/src/executor.rs
@@ -15,7 +15,7 @@ pub fn executors() -> Vec<Box<dyn Executor>> {
 }
 
 pub fn executors_id() -> Vec<String> {
-    executors()
+    filter_unavailable(&executors())
         .iter()
             .map(|x| x.id())
         .collect()
@@ -27,7 +27,15 @@ pub fn get_executor<'a, T: Into<String>>(id: T, executors: &'a Vec<Box<dyn Execu
     found
 }
 
+pub fn filter_unavailable<'a>(executors: &'a Vec<Box<dyn Executor>>) -> Vec<&Box<dyn Executor>> {
+    executors
+        .iter()
+            .filter(|x| x.available())
+        .collect()
+}
+
 pub trait Executor {
     fn id(&self) -> String;
     fn exec(&self, code: String) -> Result<String, String>;
+    fn available(&self) -> bool;
 }
\ No newline at end of file
diff --git a/src/executor/helper.rs b/src/executor/helper.rs
index 6bed093..0df2e5b 100644
--- a/src/executor/helper.rs
+++ b/src/executor/helper.rs
@@ -1,4 +1,4 @@
-use std::{fs::create_dir_all, io::Read, process::{ChildStdout, ExitStatus}};
+use std::{env, fs::{self, create_dir_all}, io::Read, process::{ChildStdout, ExitStatus}};
 
 use rand::{distributions::Alphanumeric, Rng, thread_rng};
 
@@ -41,4 +41,26 @@ pub fn get_stdout(stdout: Option<ChildStdout>) -> Result<String, String> {
     };
 
     Ok(ret)
+}
+
+
+pub fn cmd_exists<T: Into<String>, B: From<bool>>(program: T) -> B {
+    let program: String = program.into();
+
+    if let Ok(path) = env::var("PATH") {
+        const SEP: char = {
+            if cfg!(unix) {
+                ':'
+            } else {
+                ';'
+            }
+        };
+        for p in path.split(SEP) {
+            let p_str = format!("{}/{}", p, program);
+            if fs::metadata(p_str).is_ok() {
+                return true.into();
+            }
+        }
+    }
+    false.into()
 }
\ No newline at end of file
diff --git a/src/executor/javascript.rs b/src/executor/javascript.rs
index e13bbfa..13f2531 100644
--- a/src/executor/javascript.rs
+++ b/src/executor/javascript.rs
@@ -6,9 +6,14 @@ use super::Executor;
 
 use super::helper::*;
 
+#[derive(Debug, Clone, Copy)]
 pub struct NodeJSExecutor {}
 
 impl Executor for NodeJSExecutor {
+    fn available(&self) -> bool {
+        cmd_exists("node")
+    }
+
     fn id(&self) -> String {
         "javascript".into()
     }
diff --git a/src/executor/php.rs b/src/executor/php.rs
index 38cc157..52bb443 100644
--- a/src/executor/php.rs
+++ b/src/executor/php.rs
@@ -10,6 +10,10 @@ use super::helper::*;
 pub struct PhpExecutor {}
 
 impl Executor for PhpExecutor {
+    fn available(&self) -> bool {
+        cmd_exists("php")
+    }
+
     fn id(&self) -> String {
         "php".into()
     }
diff --git a/src/executor/python.rs b/src/executor/python.rs
index 37489c4..70e4b47 100644
--- a/src/executor/python.rs
+++ b/src/executor/python.rs
@@ -11,6 +11,34 @@ use super::helper::*;
 pub struct PythonExecutor {}
 
 impl Executor for PythonExecutor {
+    fn available(&self) -> bool {
+        let cmd_ok = cmd_exists("python");
+        if cmd_ok {
+            let version_check =
+                Command::new("python")
+                    .arg("--version")
+                    .stdout(Stdio::piped())
+                    .spawn();
+            if let Ok(version_check) = version_check {
+                if let Some(mut sout) = version_check.stdout {
+                    let mut buf = String::new();
+                    let res = sout.read_to_string(&mut buf);
+                    if res.is_err() {
+                        return false;
+                    }
+                    
+                    let is_py3 = buf.starts_with("Python 3");
+                    if ! is_py3 {
+                        log::warn!("`python` command is not a Python 3 interpreter.")
+                    }
+                    return is_py3
+                }
+            }
+        }
+
+        false
+    }
+
     fn id(&self) -> String {
         "python".into()
     }
diff --git a/src/main.rs b/src/main.rs
index de78901..a99c6bc 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,7 +3,7 @@
 use std::{fs::create_dir_all, net::SocketAddr, process::Stdio};
 
 use web::state::{SharedState, TemplateState};
-use executor::executors_id;
+use executor::{executors, executors_id, Executor};
 
 mod web;
 pub mod executor;
@@ -21,10 +21,34 @@ fn check() {
     if create_dir_all("/tmp/sandy-tmp").is_err() {
         panic!("Cannot create temporary directory on /tmp/sandy-tmp");
     }
+
+    let execs = executors();
+    let available = execs
+        .iter()
+            .map(|x| {
+                if ! x.available() {
+                    log::warn!("{} is not available in this environment!", x.id())
+                }
+                x
+            })
+            .filter(|x| x.available())
+            .collect::<Vec<&Box<dyn Executor>>>()
+        .len();
+
+    if available == 0 {
+        panic!("No executors are available.");
+    }
 }
 
 #[tokio::main]
 async fn main() {
+
+    if cfg!(debug_assertions) {
+        femme::with_level(log::LevelFilter::Debug)
+    } else {
+        femme::with_level(log::LevelFilter::Info)
+    }
+
     check();
     
     let state = SharedState {