diff --git a/CMakeLists.txt b/CMakeLists.txt
index 129e922..6947a82 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.16)
-project(fun VERSION 0.18.0 LANGUAGES C)
+project(fun VERSION 0.19.0 LANGUAGES C)
 
 set(CMAKE_C_STANDARD 11)
 set(CMAKE_C_STANDARD_REQUIRED ON)
diff --git a/examples/datetime_basic.fun b/examples/datetime_basic.fun
new file mode 100644
index 0000000..20d162c
--- /dev/null
+++ b/examples/datetime_basic.fun
@@ -0,0 +1,45 @@
+#!/usr/bin/env fun
+
+/*
+ * This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2025-10-04
+ */
+
+// Date/time opcode usage examples
+#include <utils/datetime.fun>
+
+fun main()
+  dt = DateTime()
+
+  ms = dt.now_ms()
+  print(join(["now ms: ", to_string(ms)], ""))
+
+  iso = dt.iso_now()
+  print(join(["iso now: ", iso], ""))
+
+  // Formatting an arbitrary timestamp (epoch ms)
+  print(dt.format(ms, "%Y-%m-%d %H:%M:%S %Z"))
+
+  // Measuring elapsed time with monotonic clock
+  start = dt.mono_ms()
+
+  sleep(100)
+  sleep(10)
+  elapsed = dt.mono_ms() - start
+  print(join(["elapsed ~100ms => ", to_string(elapsed), " ms"], ""))
+
+// Invoke main when script is executed directly
+main()
+
+/* Possible output:
+now ms: 1759531591326
+iso now: 2025-10-04T00:46:31
+2025-10-04 00:46:31 CEST
+elapsed ~100ms => 110 ms
+*/
diff --git a/lib/utils/datetime.fun b/lib/utils/datetime.fun
new file mode 100644
index 0000000..38517ca
--- /dev/null
+++ b/lib/utils/datetime.fun
@@ -0,0 +1,32 @@
+// Date/time utilities abstraction for the Fun stdlib.
+// Minimal version to validate syntax.
+
+/*
+ * Date/time utilities abstraction for the Fun stdlib.
+ * Provides a convenient class-based API over VM date/time opcodes.
+ *
+ * Methods:
+ *  - now_ms()    -> current wall clock ms since Unix epoch
+ *  - mono_ms()   -> monotonic clock ms (for measuring intervals)
+ *  - format(ms, fmt) -> format an epoch-ms timestamp using strftime format
+ *  - iso_now()   -> ISO-8601 like local timestamp (YYYY-MM-DDTHH:MM:SS)
+ */
+
+class DateTime()
+  // Current wall-clock time in milliseconds since Unix epoch
+  fun now_ms(this)
+    return time_now_ms()
+
+  // Monotonic clock in milliseconds
+  fun mono_ms(this)
+    return clock_mono_ms()
+
+  // Format an epoch-ms timestamp with a strftime() format string
+  fun format(this, ms, fmt)
+    // ensure argument order and types are okay
+    return date_format(to_number(ms), to_string(fmt))
+
+  // Convenience: ISO-like current datetime string (local time)
+  fun iso_now(this)
+    ms = time_now_ms()
+    return date_format(ms, "%Y-%m-%dT%H:%M:%S")
diff --git a/src/bytecode.c b/src/bytecode.c
index 6468910..901c67f 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -116,6 +116,30 @@ static const char *opcode_name(OpCode op) {
         case OP_HAS_KEY: return "HAS_KEY";
         case OP_READ_FILE: return "READ_FILE";
         case OP_WRITE_FILE: return "WRITE_FILE";
+        case OP_ENV: return "ENV";
+        case OP_INPUT_LINE: return "INPUT_LINE";
+        case OP_PROC_RUN: return "PROC_RUN";
+        case OP_PROC_SYSTEM: return "PROC_SYSTEM";
+        case OP_TIME_NOW_MS: return "TIME_NOW_MS";
+        case OP_CLOCK_MONO_MS: return "CLOCK_MONO_MS";
+        case OP_DATE_FORMAT: return "DATE_FORMAT";
+        case OP_THREAD_SPAWN: return "THREAD_SPAWN";
+        case OP_THREAD_JOIN: return "THREAD_JOIN";
+        case OP_SLEEP_MS: return "SLEEP_MS";
+        case OP_BAND: return "BAND";
+        case OP_BOR: return "BOR";
+        case OP_BXOR: return "BXOR";
+        case OP_BNOT: return "BNOT";
+        case OP_SHL: return "SHL";
+        case OP_SHR: return "SHR";
+        case OP_ROTL: return "ROTL";
+        case OP_ROTR: return "ROTR";
+        case OP_PCSC_ESTABLISH: return "PCSC_ESTABLISH";
+        case OP_PCSC_RELEASE: return "PCSC_RELEASE";
+        case OP_PCSC_LIST_READERS: return "PCSC_LIST_READERS";
+        case OP_PCSC_CONNECT: return "PCSC_CONNECT";
+        case OP_PCSC_DISCONNECT: return "PCSC_DISCONNECT";
+        case OP_PCSC_TRANSMIT: return "PCSC_TRANSMIT";
         default: return "???";
     }
 }
diff --git a/src/bytecode.h b/src/bytecode.h
index 6dd3a44..082cdb5 100644
--- a/src/bytecode.h
+++ b/src/bytecode.h
@@ -117,6 +117,9 @@ typedef enum {
     OP_INPUT_LINE,    // operand: 0=no prompt; 1=has prompt. Pops [prompt?]; pushes input string (no trailing newline)
     OP_PROC_RUN,      // pops command string; pushes map {"out": string, "code": int}
     OP_PROC_SYSTEM,   // pops command string; pushes exit code number
+    OP_TIME_NOW_MS,   // pushes current wall-clock time in milliseconds since Unix epoch
+    OP_CLOCK_MONO_MS, // pushes monotonic clock in milliseconds (not wall time)
+    OP_DATE_FORMAT,   // pops fmt string, ms epoch (int); pushes formatted date string using strftime
 
     // Threads
     OP_THREAD_SPAWN,  // operand: 0=no args, 1=has args; pops [args?], fn; pushes thread id (int>0)
diff --git a/src/parser.c b/src/parser.c
index 09ce41f..0f65f01 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -670,6 +670,30 @@ static int emit_primary(Bytecode *bc, const char *src, size_t len, size_t *pos)
                 free(name);
                 return 1;
             }
+            if (strcmp(name, "time_now_ms") == 0) {
+                (*pos)++; /* '(' */
+                if (!consume_char(src, len, pos, ')')) { parser_fail(*pos, "time_now_ms expects ()"); free(name); return 0; }
+                bytecode_add_instruction(bc, OP_TIME_NOW_MS, 0);
+                free(name);
+                return 1;
+            }
+            if (strcmp(name, "clock_mono_ms") == 0) {
+                (*pos)++; /* '(' */
+                if (!consume_char(src, len, pos, ')')) { parser_fail(*pos, "clock_mono_ms expects ()"); free(name); return 0; }
+                bytecode_add_instruction(bc, OP_CLOCK_MONO_MS, 0);
+                free(name);
+                return 1;
+            }
+            if (strcmp(name, "date_format") == 0) {
+                (*pos)++; /* '(' */
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "date_format expects (ms:int, fmt:string)"); free(name); return 0; }
+                if (!consume_char(src, len, pos, ',')) { parser_fail(*pos, "date_format expects 2 args"); free(name); return 0; }
+                if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "date_format expects (ms:int, fmt:string)"); free(name); return 0; }
+                if (!consume_char(src, len, pos, ')')) { parser_fail(*pos, "Expected ')' after date_format args"); free(name); return 0; }
+                bytecode_add_instruction(bc, OP_DATE_FORMAT, 0);
+                free(name);
+                return 1;
+            }
             if (strcmp(name, "env") == 0) {
                 (*pos)++; /* '(' */
                 if (!emit_expression(bc, src, len, pos)) { parser_fail(*pos, "env expects 1 argument"); free(name); return 0; }
diff --git a/src/vm.c b/src/vm.c
index 2b91edd..9e06dbe 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -326,6 +326,10 @@ void vm_run(VM *vm, Bytecode *entry) {
             #include "vm/os/thread_spawn.c"
             #include "vm/os/proc_run.c"
             #include "vm/os/proc_system.c"
+            #include "vm/os/time_now_ms.c"
+            #include "vm/os/clock_mono_ms.c"
+            #include "vm/os/date_format.c"
+
             #include "vm/pcsc/establish.c"
             #include "vm/pcsc/release.c"
             #include "vm/pcsc/list_readers.c"
diff --git a/src/vm.h b/src/vm.h
index 2dfc3f7..7028060 100644
--- a/src/vm.h
+++ b/src/vm.h
@@ -34,6 +34,7 @@ static const char *opcode_names[] = {
     "MIN","MAX","CLAMP","ABS","POW","RANDOM_SEED","RANDOM_INT",
     "MAKE_MAP","KEYS","VALUES","HAS_KEY",
     "READ_FILE","WRITE_FILE","ENV","INPUT_LINE","PROC_RUN","PROC_SYSTEM",
+    "TIME_NOW_MS","CLOCK_MONO_MS","DATE_FORMAT",
     "THREAD_SPAWN","THREAD_JOIN","SLEEP_MS",
     "BAND","BOR","BXOR","BNOT","SHL","SHR","ROTL","ROTR",
     "PCSC_ESTABLISH","PCSC_RELEASE","PCSC_LIST_READERS","PCSC_CONNECT","PCSC_DISCONNECT","PCSC_TRANSMIT"
diff --git a/src/vm/os/clock_mono_ms.c b/src/vm/os/clock_mono_ms.c
new file mode 100644
index 0000000..25206e9
--- /dev/null
+++ b/src/vm/os/clock_mono_ms.c
@@ -0,0 +1,39 @@
+/**
+ * This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2025-10-04
+ */
+
+/**
+ * @file clock_mono_ms.c
+ * @brief Implements OP_CLOCK_MONO_MS to push monotonic clock in ms.
+ *
+ * Stack before: []
+ * Stack after: [int ms]
+ */
+
+#include <time.h>
+#include <stdint.h>
+
+case OP_CLOCK_MONO_MS: {
+    int64_t ms;
+#if defined(CLOCK_MONOTONIC) && !defined(_WIN32)
+    struct timespec ts;
+    if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
+        ms = (int64_t)ts.tv_sec * 1000 + (int64_t)(ts.tv_nsec / 1000000);
+    } else {
+        time_t s = time(NULL);
+        ms = (int64_t)s * 1000;
+    }
+#else
+    time_t s = time(NULL);
+    ms = (int64_t)s * 1000;
+#endif
+    push_value(vm, make_int(ms));
+    break;
+}
diff --git a/src/vm/os/date_format.c b/src/vm/os/date_format.c
new file mode 100644
index 0000000..6e6ba99
--- /dev/null
+++ b/src/vm/os/date_format.c
@@ -0,0 +1,72 @@
+/**
+* This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2025-10-04
+ */
+
+/**
+ * @file date_format.c
+ * @brief Implements OP_DATE_FORMAT to format an epoch milliseconds timestamp using strftime.
+ *
+ * Behavior:
+ * - Pops fmt string, then milliseconds since Unix epoch (int).
+ * - Formats the local time according to fmt and pushes a string.
+ *
+ * Errors:
+ * - If types are wrong, prints error and pushes empty string to keep stack safe.
+ */
+
+#include <time.h>
+#include <string.h>
+#include <stdlib.h>
+
+case OP_DATE_FORMAT: {
+    Value fmt = pop_value(vm);
+    Value ms  = pop_value(vm);
+    if (ms.type != VAL_INT || fmt.type != VAL_STRING) {
+        fprintf(stderr, "DATE_FORMAT expects (fmt:string, ms:int)\n");
+        if (ms.type != VAL_NIL) free_value(ms);
+        if (fmt.type != VAL_NIL) free_value(fmt);
+        push_value(vm, make_string(""));
+        break;
+    }
+    time_t secs = (time_t)(ms.i / 1000);
+    struct tm tmv;
+#if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 1
+    localtime_r(&secs, &tmv);
+#else
+    struct tm *ptm = localtime(&secs);
+    if (!ptm) {
+        free_value(ms); free_value(fmt);
+        push_value(vm, make_string(""));
+        break;
+    }
+    tmv = *ptm;
+#endif
+    /* Determine buffer size by attempting once with a reasonable size and retrying if needed */
+    size_t cap = 128;
+    char *buf = (char*)malloc(cap);
+    size_t n = strftime(buf, cap, fmt.s, &tmv);
+    if (n == 0) {
+        /* try larger */
+        cap = 512;
+        buf = (char*)realloc(buf, cap);
+        n = strftime(buf, cap, fmt.s, &tmv);
+    }
+    Value out;
+    if (n == 0) {
+        out = make_string("");
+    } else {
+        out = make_string(buf);
+    }
+    free(buf);
+    free_value(ms);
+    free_value(fmt);
+    push_value(vm, out);
+    break;
+}
diff --git a/src/vm/os/time_now_ms.c b/src/vm/os/time_now_ms.c
new file mode 100644
index 0000000..389e19c
--- /dev/null
+++ b/src/vm/os/time_now_ms.c
@@ -0,0 +1,39 @@
+/**
+* This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the Apache-2.0 license.
+ * https://opensource.org/license/apache-2-0
+ *
+ * Added: 2025-10-04
+ */
+
+/**
+ * @file time_now_ms.c
+ * @brief Implements OP_TIME_NOW_MS to push current wall-clock time in ms since Unix epoch.
+ *
+ * Stack before: []
+ * Stack after: [int ms]
+ */
+
+#include <time.h>
+#include <stdint.h>
+
+case OP_TIME_NOW_MS: {
+    int64_t ms;
+#if defined(CLOCK_REALTIME) && !defined(_WIN32)
+    struct timespec ts;
+    if (clock_gettime(CLOCK_REALTIME, &ts) == 0) {
+        ms = (int64_t)ts.tv_sec * 1000 + (int64_t)(ts.tv_nsec / 1000000);
+    } else {
+        time_t s = time(NULL);
+        ms = (int64_t)s * 1000;
+    }
+#else
+    time_t s = time(NULL);
+    ms = (int64_t)s * 1000;
+#endif
+    push_value(vm, make_int(ms));
+    break;
+}