diff --git a/crates/zapcode-core/src/compiler/instruction.rs b/crates/zapcode-core/src/compiler/instruction.rs
index c8b8ef0..e55e087 100644
--- a/crates/zapcode-core/src/compiler/instruction.rs
+++ b/crates/zapcode-core/src/compiler/instruction.rs
@@ -60,6 +60,8 @@ pub enum Instruction {
     Call(usize),
     Return,
     CallExternal(String, usize),
+    /// Call a global builtin function by name (e.g. parseInt, isNaN, Number).
+    CallBuiltin(String, usize),
 
     // Control flow
     Jump(usize),
diff --git a/crates/zapcode-core/src/compiler/mod.rs b/crates/zapcode-core/src/compiler/mod.rs
index 9d2284e..ced4930 100644
--- a/crates/zapcode-core/src/compiler/mod.rs
+++ b/crates/zapcode-core/src/compiler/mod.rs
@@ -34,6 +34,15 @@ struct Compiler {
     external_functions: HashSet<String>,
 }
 
+/// Global functions dispatched via `Instruction::CallBuiltin`. Kept in sync with
+/// `builtins::call_global_function`.
+fn is_global_builtin_fn(name: &str) -> bool {
+    matches!(
+        name,
+        "parseInt" | "parseFloat" | "isNaN" | "isFinite" | "String" | "Number" | "Boolean"
+    )
+}
+
 struct LoopInfo {
     break_patches: Vec<usize>,
     continue_patches: Vec<usize>,
@@ -919,6 +928,17 @@ impl Compiler {
                         return Ok(());
                     }
                 }
+                // Direct call to a global builtin function (parseInt, Number, …),
+                // unless shadowed by a local of the same name.
+                if let Expr::Ident(name) = callee.as_ref() {
+                    if self.resolve_local(name).is_none() && is_global_builtin_fn(name) {
+                        for arg in args {
+                            self.compile_expr(arg)?;
+                        }
+                        self.emit(Instruction::CallBuiltin(name.clone(), args.len()));
+                        return Ok(());
+                    }
+                }
                 self.compile_expr(callee)?;
                 for arg in args {
                     self.compile_expr(arg)?;
diff --git a/crates/zapcode-core/src/vm/builtins.rs b/crates/zapcode-core/src/vm/builtins.rs
index 2b20d44..7313dcc 100644
--- a/crates/zapcode-core/src/vm/builtins.rs
+++ b/crates/zapcode-core/src/vm/builtins.rs
@@ -707,6 +707,136 @@ fn call_array_method(arr: &[Value], method: &str, args: &[Value]) -> Result<Opti
     Ok(Some(result))
 }
 
+/// Dispatch a global builtin function call (parseInt, isNaN, Number, …).
+/// Returns `None` only for an unrecognized name (the compiler shouldn't emit one).
+pub fn call_global_function(name: &str, args: &[Value]) -> Option<Value> {
+    let value = match name {
+        "parseInt" => parse_int(args),
+        "parseFloat" => parse_float(args),
+        "isNaN" => Value::Bool(arg_num(args, 0).is_nan()),
+        "isFinite" => Value::Bool(arg_num(args, 0).is_finite()),
+        "String" => match args.first() {
+            Some(v) => Value::String(Arc::from(v.to_js_string().as_str())),
+            None => Value::String(Arc::from("")),
+        },
+        "Number" => match args.first() {
+            Some(v) => narrow_number(v.to_number()),
+            None => Value::Int(0),
+        },
+        "Boolean" => Value::Bool(args.first().map(|v| v.is_truthy()).unwrap_or(false)),
+        _ => return None,
+    };
+    Some(value)
+}
+
+/// Represent a finite integral number as `Int` (nicer `===`), else `Float`.
+fn narrow_number(n: f64) -> Value {
+    if n.is_finite() && n.fract() == 0.0 && n.abs() < i64::MAX as f64 {
+        Value::Int(n as i64)
+    } else {
+        Value::Float(n)
+    }
+}
+
+fn parse_int(args: &[Value]) -> Value {
+    let s = args.first().map(|v| v.to_js_string()).unwrap_or_default();
+    let chars: Vec<char> = s.trim_start().chars().collect();
+    let mut i = 0;
+    let mut sign = 1.0;
+    if i < chars.len() && (chars[i] == '+' || chars[i] == '-') {
+        if chars[i] == '-' {
+            sign = -1.0;
+        }
+        i += 1;
+    }
+
+    let radix_arg = args.get(1).map(|v| v.to_number()).unwrap_or(f64::NAN);
+    let mut radix: i64 = if radix_arg.is_nan() || radix_arg == 0.0 {
+        0
+    } else {
+        radix_arg as i64
+    };
+    if radix != 0 && !(2..=36).contains(&radix) {
+        return Value::Float(f64::NAN);
+    }
+    if (radix == 0 || radix == 16)
+        && i + 1 < chars.len()
+        && chars[i] == '0'
+        && (chars[i + 1] == 'x' || chars[i + 1] == 'X')
+    {
+        i += 2;
+        radix = 16;
+    }
+    if radix == 0 {
+        radix = 10;
+    }
+
+    let mut value = 0.0;
+    let mut any = false;
+    while i < chars.len() {
+        match chars[i].to_digit(36) {
+            Some(d) if (d as i64) < radix => {
+                value = value * radix as f64 + d as f64;
+                any = true;
+                i += 1;
+            }
+            _ => break,
+        }
+    }
+    if !any {
+        return Value::Float(f64::NAN);
+    }
+    narrow_number(sign * value)
+}
+
+fn parse_float(args: &[Value]) -> Value {
+    let s = args.first().map(|v| v.to_js_string()).unwrap_or_default();
+    let s = s.trim_start();
+    if s.starts_with("Infinity") || s.starts_with("+Infinity") {
+        return Value::Float(f64::INFINITY);
+    }
+    if s.starts_with("-Infinity") {
+        return Value::Float(f64::NEG_INFINITY);
+    }
+    let b = s.as_bytes();
+    let n = b.len();
+    let mut i = 0;
+    if i < n && (b[i] == b'+' || b[i] == b'-') {
+        i += 1;
+    }
+    let mut saw_digit = false;
+    while i < n && b[i].is_ascii_digit() {
+        i += 1;
+        saw_digit = true;
+    }
+    if i < n && b[i] == b'.' {
+        i += 1;
+        while i < n && b[i].is_ascii_digit() {
+            i += 1;
+            saw_digit = true;
+        }
+    }
+    if saw_digit && i < n && (b[i] == b'e' || b[i] == b'E') {
+        let mut j = i + 1;
+        if j < n && (b[j] == b'+' || b[j] == b'-') {
+            j += 1;
+        }
+        if j < n && b[j].is_ascii_digit() {
+            while j < n && b[j].is_ascii_digit() {
+                j += 1;
+            }
+            i = j;
+        }
+    }
+    if !saw_digit {
+        return Value::Float(f64::NAN);
+    }
+    s[..i]
+        .parse::<f64>()
+        .map(Value::Float)
+        .unwrap_or(Value::Float(f64::NAN))
+}
+
 // ── Object static methods ────────────────────────────────────────────
 
 fn call_object_method(method: &str, args: &[Value]) -> Result<Option<Value>> {
diff --git a/crates/zapcode-core/src/vm/mod.rs b/crates/zapcode-core/src/vm/mod.rs
index f0f39d9..eb918db 100644
--- a/crates/zapcode-core/src/vm/mod.rs
+++ b/crates/zapcode-core/src/vm/mod.rs
@@ -1808,6 +1808,22 @@ impl Vm {
                     snapshot,
                 }));
             }
+            Instruction::CallBuiltin(name, arg_count) => {
+                let mut args = Vec::with_capacity(arg_count);
+                for _ in 0..arg_count {
+                    args.push(self.pop()?);
+                }
+                args.reverse();
+                match builtins::call_global_function(&name, &args) {
+                    Some(val) => self.push(val)?,
+                    None => {
+                        return Err(ZapcodeError::TypeError(format!(
+                            "{} is not a function",
+                            name
+                        )))
+                    }
+                }
+            }
 
             // Control flow
             Instruction::Jump(target) => {
diff --git a/crates/zapcode-core/tests/builtins.rs b/crates/zapcode-core/tests/builtins.rs
index c69bb02..2651c70 100644
--- a/crates/zapcode-core/tests/builtins.rs
+++ b/crates/zapcode-core/tests/builtins.rs
@@ -574,3 +574,43 @@ fn test_array_some_empty() {
     let result = eval_ts("[].some((x) => x > 0)").unwrap();
     assert_eq!(result, Value::Bool(false));
 }
+
+// ── global builtin functions (regression: parseInt/parseFloat were missing) ──
+
+#[test]
+fn test_parse_int() {
+    assert_eq!(eval_ts("parseInt('42px')").unwrap(), Value::Int(42));
+    assert_eq!(eval_ts("parseInt('  -7')").unwrap(), Value::Int(-7));
+    assert_eq!(eval_ts("parseInt('0xFF')").unwrap(), Value::Int(255));
+    assert_eq!(eval_ts("parseInt('101', 2)").unwrap(), Value::Int(5));
+    assert_eq!(eval_ts("parseInt('ff', 16)").unwrap(), Value::Int(255));
+    assert!(matches!(eval_ts("parseInt('abc')").unwrap(), Value::Float(f) if f.is_nan()));
+}
+
+#[test]
+fn test_parse_float() {
+    assert_eq!(eval_ts("parseFloat('2.5xyz')").unwrap(), Value::Float(2.5));
+    assert_eq!(
+        eval_ts("parseFloat('  1e3')").unwrap(),
+        Value::Float(1000.0)
+    );
+    assert!(matches!(eval_ts("parseFloat('nope')").unwrap(), Value::Float(f) if f.is_nan()));
+}
+
+#[test]
+fn test_isnan_isfinite_number_string_boolean() {
+    assert_eq!(eval_ts("isNaN(NaN)").unwrap(), Value::Bool(true));
+    assert_eq!(eval_ts("isNaN(3)").unwrap(), Value::Bool(false));
+    assert_eq!(eval_ts("isFinite(1/0)").unwrap(), Value::Bool(false));
+    assert_eq!(eval_ts("isFinite(42)").unwrap(), Value::Bool(true));
+    assert_eq!(eval_ts("Number('42')").unwrap(), Value::Int(42));
+    assert_eq!(eval_ts("String(42)").unwrap(), Value::String("42".into()));
+    assert_eq!(eval_ts("Boolean(0)").unwrap(), Value::Bool(false));
+}
+
+#[test]
+fn test_global_builtin_shadowed_by_local() {
+    // A local named `Number` must win over the builtin.
+    let r = eval_ts("const Number = (x) => x + 1; Number(41)").unwrap();
+    assert_eq!(r, Value::Int(42));
+}