diff --git a/CMakeLists.txt b/CMakeLists.txt
index 901ac73..718a11b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -80,6 +80,12 @@ add_library(lib${PROJECT_NAME} SHARED
         src/vm/expr.cc
         src/vm/expr.hh
         src/vm/location.hh
+        src/assembler/lexer.cc
+        src/assembler/lexer.hh
+        src/assembler/assembler.cc
+        src/assembler/assembler.hh
+        src/assembler/as_exceptions.hh
+        src/bytecode/bc_exceptions.hh
 )
 
 target_compile_options(lib${PROJECT_NAME} PRIVATE ${warnings})
@@ -88,6 +94,8 @@ target_compile_options(lib${PROJECT_NAME} PRIVATE ${warnings})
 # tests
 #
 
+enable_testing()
+
 add_executable(${PROJECT_NAME}-bytecode-test src/bytecode/tests.cc)
 target_link_libraries(${PROJECT_NAME}-bytecode-test lib${PROJECT_NAME} gtest_main)
 add_test(NAME tyche_bytecode_test COMMAND ${PROJECT_NAME}-bytecode-test)
@@ -96,6 +104,10 @@ add_executable(${PROJECT_NAME}-vm-test src/vm/tests.cc)
 target_link_libraries(${PROJECT_NAME}-vm-test lib${PROJECT_NAME} gtest_main)
 add_test(NAME tyche_vm_test COMMAND ${PROJECT_NAME}-vm-test)
 
+add_executable(${PROJECT_NAME}-as-test src/assembler/tests.cc)
+target_link_libraries(${PROJECT_NAME}-as-test lib${PROJECT_NAME} gtest_main)
+add_test(NAME tyche_as_test COMMAND ${PROJECT_NAME}-as-test)
+
 #
 # check for leaks
 #
diff --git a/src/assembler/as_exceptions.hh b/src/assembler/as_exceptions.hh
new file mode 100644
index 0000000..9338341
--- /dev/null
+++ b/src/assembler/as_exceptions.hh
@@ -0,0 +1,18 @@
+#ifndef TYCHE_VM_EXCEPTIONS_HH
+#define TYCHE_VM_EXCEPTIONS_HH
+
+#include <stdexcept>
+#include <string>
+
+namespace tyche::as {
+
+class AssemblyError : public std::runtime_error
+{
+public:
+    explicit AssemblyError(std::string const& str, size_t line, size_t column)
+        : std::runtime_error((str + " at: line " + std::to_string(line) + ", column: " + std::to_string(column)).c_str()) {}
+};
+
+}
+
+#endif //TYCHE_VM_EXCEPTIONS_HH
diff --git a/src/assembler/assembler.cc b/src/assembler/assembler.cc
new file mode 100644
index 0000000..d189a26
--- /dev/null
+++ b/src/assembler/assembler.cc
@@ -0,0 +1,98 @@
+#include "assembler.hh"
+
+#include <unordered_map>
+
+#include "as_exceptions.hh"
+#include "../bytecode/bytecode.hh"
+#include "../vm/instruction.hh"
+
+using namespace std::string_literals;
+
+namespace tyche::as {
+
+ByteArray Assembler::assemble()
+{
+    bc::BytecodePrototype bp;
+
+    lexer_.reset();
+
+    enum class Section { Const, Function } section;
+    uint32_t function_id = 0;
+
+    for (;;) {
+        Token t = lexer_.ingest();
+        if (t.type == TokenType::Enter)
+            continue;
+
+        if (t.type == TokenType::Directive) {
+            if (std::get<std::string>(t.token) == ".const") {
+                section = Section::Const;
+                expect_token(TokenType::Enter);
+            } else if (std::get<std::string>(t.token) == ".func") {
+                section = Section::Function;
+                function_id = std::get<int>(expect_token(TokenType::Integer));
+                if (function_id >= bp.functions.size())
+                    bp.functions.resize(function_id + 1, { 0, 0 });
+                expect_token(TokenType::Enter);
+            } else {
+                throw AssemblyError("Invalid directive " + std::get<std::string>(t.token), t.line, t.column);
+            }
+
+        } else if (section == Section::Const && t.type == TokenType::Integer) {
+            int index = std::get<int>(t.token);
+            if ((size_t) index >= bp.constants.size())
+                bp.constants.resize(index + 1);
+            expect_token(TokenType::Colon);
+            Token tt = lexer_.ingest();
+            if (tt.type == TokenType::Float)
+                bp.constants[index] = std::get<float>(tt.token);
+            else if (tt.type == TokenType::String)
+                bp.constants[index] = std::get<std::string>(tt.token);
+            else
+                throw AssemblyError("Expected float or string as constant", tt.line, tt.column);
+            expect_token(TokenType::Enter);
+
+        } else if (section == Section::Function && t.type == TokenType::Instruction) {
+            std::string instruction = std::get<std::string>(t.token);
+            std::optional<int> oper = {};
+            Token tt = lexer_.ingest();
+            if (tt.type == TokenType::Integer) {
+                oper = std::get<int>(tt.token);
+                tt = lexer_.ingest();
+            }
+
+            auto oinst = vm::translate_instruction(instruction, oper);
+            if (!oinst)
+                throw AssemblyError("Invalid or misused instruction '" + instruction + "'", tt.line, tt.column);
+
+            bp.functions.at(function_id).code.append_byte((uint8_t) *oinst);
+            switch (vm::instruction_operand_type(*oinst)) {
+                case vm::OperandType::Int8:  bp.functions.at(function_id).code.append_int8((int8_t) *oper); break;
+                case vm::OperandType::Int16: bp.functions.at(function_id).code.append_int16((int16_t) *oper); break;
+                case vm::OperandType::Int32: bp.functions.at(function_id).code.append_int32(*oper); break;
+                case vm::OperandType::NoOperand: default:
+            }
+
+            if (tt.type != TokenType::Enter)
+                throw AssemblyError("Expected enter", tt.line, tt.column);
+
+        } else if (t.type == TokenType::EOF_) {
+            break;
+
+        } else if (t.type != TokenType::Enter) {
+            throw AssemblyError("Unexpected token of type " + token_type_name(t.type) + ")", t.line, t.column);
+        }
+    }
+
+    return bc::Bytecode::generate(bp);
+}
+
+TokenValue Assembler::expect_token(TokenType type)
+{
+    Token t = lexer_.ingest();
+    if (t.type != type)
+        throw AssemblyError("Expected " + token_type_name(t.type), t.line, t.column);
+    return t.token;
+}
+
+} // tyche
diff --git a/src/assembler/assembler.hh b/src/assembler/assembler.hh
new file mode 100644
index 0000000..00f87e5
--- /dev/null
+++ b/src/assembler/assembler.hh
@@ -0,0 +1,27 @@
+#ifndef TYCHE_ASSEMBLER_HH
+#define TYCHE_ASSEMBLER_HH
+
+#include <optional>
+#include <string>
+
+#include "lexer.hh"
+#include "../common/bytearray.hh"
+#include "../bytecode/bytecodeprototype.hh"
+
+namespace tyche::as {
+
+class Assembler {
+public:
+    explicit Assembler(std::string source) : lexer_(std::move(source)) {}
+
+    [[nodiscard]] ByteArray assemble();
+
+private:
+    Lexer lexer_;
+
+    TokenValue expect_token(TokenType type);
+};
+
+} // tyche
+
+#endif //TYCHE_ASSEMBLER_HH
diff --git a/src/assembler/lexer.cc b/src/assembler/lexer.cc
new file mode 100644
index 0000000..03b3836
--- /dev/null
+++ b/src/assembler/lexer.cc
@@ -0,0 +1,120 @@
+#include "lexer.hh"
+
+#include "as_exceptions.hh"
+
+namespace tyche::as {
+
+std::string token_type_name(TokenType type)
+{
+    switch (type) {
+        case TokenType::BOF: return "BOF";
+        case TokenType::Directive: return "directive";
+        case TokenType::Instruction: return "instruction";
+        case TokenType::Integer: return "integer";
+        case TokenType::Float: return "float";
+        case TokenType::String: return "string";
+        case TokenType::Enter: return "enter";
+        case TokenType::Colon: return "colon";
+        case TokenType::EOF_: return "EOF";
+        default: return "???";
+    }
+}
+
+void Lexer::reset()
+{
+    pos_ = 0;
+    ingest_next_token();
+}
+
+Token Lexer::peek() const
+{
+    return current_token_;
+}
+
+Token Lexer::ingest()
+{
+    Token t = current_token_;
+    ingest_next_token();
+    return t;
+}
+
+void Lexer::ingest_next_token()
+{
+    size_t current_line_pos = 1;
+    size_t current_line = 1;
+
+    if (pos_ >= source_.size()) {
+        current_token_ = { TokenType::EOF_ };
+        return;
+    }
+
+    char c = source_.at(pos_);
+
+    TokenType type {};
+    std::string stoken;
+    TokenValue value = std::monostate();
+
+    if (c == '.') {
+        type = TokenType::Directive;
+        stoken += '.';
+        while (c = source_.at(++pos_), isalpha(c) || c == '_')
+            stoken += c;
+        value = stoken;
+    } else if (c == '"') {
+        type = TokenType::String;
+        ++pos_;
+        while (true) {
+            if (source_.at(pos_) == '\\') {   // TODO - improve this for special characters
+                ++pos_;
+            } else if (source_.at(pos_) == '"') {
+                ++pos_;
+                break;
+            } else if (pos_ >= source_.size()) {
+                throw AssemblyError("Unterminated string", current_line, pos_ - current_line_pos);
+            }
+            stoken += source_.at(pos_++);
+        }
+        value = stoken;
+    } else if (isdigit(c) || c == '-') {
+        type = TokenType::Integer;
+        stoken += c;
+        while (c = source_.at(++pos_), isdigit(c) || c == '.') {
+            stoken += c;
+            if (c == '.') {
+                if (type == TokenType::Integer)
+                    type = TokenType::Float;
+                else
+                    throw AssemblyError("Double point in floating point number", current_line, pos_ - current_line_pos);
+            }
+        }
+        if (type == TokenType::Integer)
+            value = std::stoi(stoken);
+        else
+            value = std::stof(stoken);
+    } else if (isalpha(c)) {
+        type = TokenType::Instruction;
+        stoken += c;
+        while (c = source_.at(++pos_), isalpha(c))
+            stoken += c;
+        value = stoken;
+    } else if (c == ':') {
+        type = TokenType::Colon;
+        ++pos_;
+    } else if (c == '\n') {
+        type = TokenType::Enter;
+        value = "\n";
+        ++pos_;
+        ++current_line;
+        current_line_pos = pos_;
+    } else {
+        throw AssemblyError(std::string("Unexpected character '") + c + "' (ascii: " + std::to_string((int) c) + ")", current_line, pos_ - current_line_pos);
+    }
+
+    // skip ignored tokens
+    while (pos_ < source_.size() && (source_.at(pos_) == ' ' || source_.at(pos_) == '\t' || source_.at(pos_) == '\r'))
+        ++pos_;
+
+    current_token_ = { .type = type, .token = value, .line = current_line, .column = pos_ - current_line_pos };
+}
+
+} // tyche
diff --git a/src/assembler/lexer.hh b/src/assembler/lexer.hh
new file mode 100644
index 0000000..eab14aa
--- /dev/null
+++ b/src/assembler/lexer.hh
@@ -0,0 +1,45 @@
+#ifndef TYCHE_LEXER_HH
+#define TYCHE_LEXER_HH
+
+#include <string>
+#include <utility>
+#include <variant>
+
+namespace tyche::as {
+
+enum class TokenType {
+    BOF, Directive, Instruction, Integer, Float, String, Enter, Colon, EOF_
+};
+
+using TokenValue = std::variant<std::monostate, int, float, std::string>;
+
+struct Token {
+    TokenType   type;
+    TokenValue  token = std::monostate();
+    size_t      line = 0;
+    size_t      column = 0;
+
+    friend bool operator==(Token const& lhs, Token const& rhs) { return std::tie(lhs.type, lhs.token) == std::tie(rhs.type, rhs.token); }
+};
+
+std::string token_type_name(TokenType type);
+
+class Lexer {
+public:
+    explicit Lexer(std::string source) : source_(std::move(source)) { reset(); }
+
+    void reset();
+    [[nodiscard]] Token peek() const;
+    [[nodiscard]] Token ingest();
+
+private:
+    const std::string source_;
+    size_t pos_ = 0;
+    Token current_token_ { TokenType::BOF };
+
+    void ingest_next_token();
+};
+
+} // tyche
+
+#endif //TYCHE_LEXER_HH
diff --git a/src/assembler/tests.cc b/src/assembler/tests.cc
new file mode 100644
index 0000000..06b446a
--- /dev/null
+++ b/src/assembler/tests.cc
@@ -0,0 +1,76 @@
+#include "assembler.hh"
+#include "gtest/gtest.h"
+
+#include "../bytecode/bytecodeprototype.hh"
+#include "../bytecode/bytecode.hh"
+#include "../vm/instruction.hh"
+
+using namespace tyche;
+using namespace tyche::as;
+using namespace tyche::bc;
+using namespace tyche::vm;
+
+TEST(Lexer, Lexer)
+{
+    Token t;
+    Lexer lexer(".dir push 382 -12 3.14 -12.8 \"Hello\" \"Hel\\\"lo\"\n");
+
+    ASSERT_EQ(lexer.ingest(), (Token { TokenType::Directive, ".dir" }));
+    ASSERT_EQ(lexer.ingest(), (Token { TokenType::Instruction, "push" }));
+    t = lexer.ingest(); ASSERT_EQ(t.type, TokenType::Integer); ASSERT_EQ(std::get<int>(t.token), 382);
+    t = lexer.ingest(); ASSERT_EQ(t.type, TokenType::Integer); ASSERT_EQ(std::get<int>(t.token), -12);
+    t = lexer.ingest(); ASSERT_EQ(t.type, TokenType::Float); ASSERT_FLOAT_EQ(std::get<float>(t.token), 3.14f);
+    t = lexer.ingest(); ASSERT_EQ(t.type, TokenType::Float); ASSERT_FLOAT_EQ(std::get<float>(t.token), -12.8f);
+    ASSERT_EQ(lexer.ingest(), (Token { TokenType::String, "Hello" }));
+    ASSERT_EQ(lexer.ingest(), (Token { TokenType::String, "Hel\"lo" }));
+    ASSERT_EQ(lexer.ingest(), (Token { TokenType::Enter, "\n" }));
+    ASSERT_EQ(lexer.ingest(), (Token { TokenType::EOF_ }));
+    ASSERT_EQ(lexer.ingest(), (Token { TokenType::EOF_ }));
+    ASSERT_EQ(lexer.ingest(), (Token { TokenType::EOF_ }));
+
+    lexer.reset();
+    ASSERT_EQ(lexer.ingest(), (Token { TokenType::Directive, ".dir" }));
+}
+
+TEST(Assember, Assembler)
+{
+    BytecodePrototype bp;
+    bp.constants.emplace_back(3.14f);
+    bp.constants.emplace_back("Hello world");
+    bp.functions.emplace_back(0, 0);
+    bp.functions.at(0).code.append_byte((uint8_t) Instruction::PushInt8);
+    bp.functions.at(0).code.append_int8(2);
+    bp.functions.at(0).code.append_byte((uint8_t) Instruction::PushInt8);
+    bp.functions.at(0).code.append_int8(3);
+    bp.functions.at(0).code.append_byte((uint8_t) Instruction::Sum);
+    bp.functions.at(0).code.append_byte((uint8_t) Instruction::Return);
+    bp.functions.emplace_back(0, 0);
+    bp.functions.at(1).code.append_byte((uint8_t) Instruction::PushInt16);
+    bp.functions.at(1).code.append_int16(5000);
+    bp.functions.at(1).code.append_byte((uint8_t) Instruction::Return);
+    ByteArray expected = Bytecode::generate(bp);
+
+    std::string src = R"(
+.const
+    0: 3.14
+    1: "Hello world"
+
+.func 0
+    pushi   2
+    pushi   3
+    sum
+    ret
+.func 1
+    pushi   5000
+    ret
+)";
+
+    ByteArray actual = Assembler(src).assemble();
+    ASSERT_EQ(expected, actual);
+}
+
+int main(int argc, char** argv)
+{
+    testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}
diff --git a/src/bytecode/bc_exceptions.hh b/src/bytecode/bc_exceptions.hh
new file mode 100644
index 0000000..f5a83c3
--- /dev/null
+++ b/src/bytecode/bc_exceptions.hh
@@ -0,0 +1,15 @@
+#ifndef TYCHE_BC_EXCEPTIONS_HH
+#define TYCHE_BC_EXCEPTIONS_HH
+
+#include <stdexcept>
+
+namespace tyche::bc {
+
+class BytecodeParsingError : public std::runtime_error {
+public:
+    explicit BytecodeParsingError(std::string const& str) : std::runtime_error(str.c_str()) {}
+};
+
+}
+
+#endif //TYCHE_BC_EXCEPTIONS_HH
diff --git a/src/bytecode/bytecode.cc b/src/bytecode/bytecode.cc
index 1dd8d02..996ba2e 100644
--- a/src/bytecode/bytecode.cc
+++ b/src/bytecode/bytecode.cc
@@ -1,4 +1,6 @@
 #include "bytecode.hh"
+
+#include "bc_exceptions.hh"
 #include "../common/overloaded.hh"
 
 namespace tyche::bc {
diff --git a/src/bytecode/bytecodeprototype.hh b/src/bytecode/bytecodeprototype.hh
index df92c81..5a1bb58 100644
--- a/src/bytecode/bytecodeprototype.hh
+++ b/src/bytecode/bytecodeprototype.hh
@@ -14,7 +14,7 @@ struct BytecodePrototype {
     struct Function {
         uint16_t  n_pars;
         uint16_t  n_locals;
-        ByteArray code;
+        ByteArray code {};
 
         Function(uint16_t n_pars_, uint16_t n_locals_) : n_pars(n_pars_), n_locals(n_locals_), code(ByteArray {}) {}
     };
diff --git a/src/common/bytearray.hh b/src/common/bytearray.hh
index 3cf6ef6..c20a011 100644
--- a/src/common/bytearray.hh
+++ b/src/common/bytearray.hh
@@ -47,15 +47,12 @@ public:
 
     [[nodiscard]] std::string hexdump() const;
 
+    friend bool operator==(ByteArray const& lhs, ByteArray const& rhs) { return lhs.data_ == rhs.data_; }
+
 private:
     std::vector<uint8_t> data_ {};
 };
 
-class BytecodeParsingError : public std::runtime_error {
-public:
-    explicit BytecodeParsingError(std::string const& str) : std::runtime_error(str.c_str()) {}
-};
-
 }
 
 #endif //TYCHE_BYTEARRAY_HH
diff --git a/src/vm/instruction.cc b/src/vm/instruction.cc
index 5508962..f719fb8 100644
--- a/src/vm/instruction.cc
+++ b/src/vm/instruction.cc
@@ -1,7 +1,62 @@
 #include "instruction.hh"
 
+#include <limits>
+#include <unordered_map>
+
 namespace tyche::vm {
 
+const std::unordered_map<std::string, vm::Instruction> instruction_names = {
+    { "pushi", vm::Instruction::PushInt8 },
+    { "pushc", vm::Instruction::PushConstant8 },
+    { "pushz", vm::Instruction::PushZero },
+    { "pusht", vm::Instruction::PushTrue },
+    { "newa",  vm::Instruction::NewArray },
+    { "newt",  vm::Instruction::NewTable },
+    { "pop",   vm::Instruction::Pop },
+    { "dup",   vm::Instruction::Duplicate },
+    { "setl",  vm::Instruction::SetLocal8 },
+    { "getl",  vm::Instruction::GetLocal8 },
+    { "setg",  vm::Instruction::SetGlobal8 },
+    { "getl",  vm::Instruction::GetGlobal8 },
+    { "call8", vm::Instruction::Call8 },
+    { "ret",   vm::Instruction::Return },
+    { "retn",  vm::Instruction::ReturnNil },
+    { "getkv", vm::Instruction::GetKeyValue },
+    { "setkv", vm::Instruction::SetKeyValue },
+    { "geta",  vm::Instruction::GetArrayItem },
+    { "seta",  vm::Instruction::SetArrayItem },
+    { "appnd", vm::Instruction::Append },
+    { "next",  vm::Instruction::Next },
+    { "smt",   vm::Instruction::SetMetatable },
+    { "mt",    vm::Instruction::GetMetatable },
+    { "sum",   vm::Instruction::Sum },
+    { "sub",   vm::Instruction::Subtract },
+    { "mul",   vm::Instruction::Multiply },
+    { "div",   vm::Instruction::Divide },
+    { "idiv",  vm::Instruction::DivideInt },
+    { "eq",    vm::Instruction::Equals },
+    { "neq",   vm::Instruction::NotEquals },
+    { "lt",    vm::Instruction::LessThan },
+    { "lte",   vm::Instruction::LessThanEq },
+    { "gt",    vm::Instruction::GreaterThan },
+    { "gte",   vm::Instruction::GreaterThanEq },
+    { "and",   vm::Instruction::And },
+    { "or",    vm::Instruction::Or },
+    { "xor",   vm::Instruction::Xor },
+    { "len",   vm::Instruction::Len },
+    { "type",  vm::Instruction::Type },
+    { "cast",  vm::Instruction::Cast },
+    { "ver",   vm::Instruction::Version },
+    { "bz",    vm::Instruction::BranchIfZero8 },
+    { "bnz",   vm::Instruction::BranchIfNotZero8 },
+    { "jmp",   vm::Instruction::Jump8 },
+    { "cmpl",  vm::Instruction::Compile },
+    { "asmbl", vm::Instruction::Assemble },
+    { "load",  vm::Instruction::Load },
+};
+
+
+
 std::pair<std::string, size_t> debug_instruction(Instruction inst, int oper)
 {
     std::string out;
@@ -142,4 +197,27 @@ OperandType instruction_operand_type(Instruction inst)
     return OperandType::NoOperand;
 }
 
+std::optional<Instruction> translate_instruction(std::string const& txt, std::optional<int> op)
+{
+    auto it = instruction_names.find(txt);
+    if (it == instruction_names.end())
+        return {};
+    Instruction inst = it->second;
+    OperandType optype = instruction_operand_type(inst);
+
+    if (optype == OperandType::NoOperand && op)
+        return {};
+    if (optype != OperandType::NoOperand && !op)
+        return {};
+
+    if (optype == OperandType::NoOperand)
+        return inst;
+
+    if (op >= std::numeric_limits<int8_t>::min() && op <= std::numeric_limits<int8_t>::max())
+        return inst;
+    if (op >= std::numeric_limits<int16_t>::min() && op <= std::numeric_limits<int16_t>::max())
+        return (Instruction) ((uint8_t) inst + OPCODE_NEXT_SIZE);
+    return (Instruction) ((uint8_t) inst + (OPCODE_NEXT_SIZE * 2));
+}
+
 }
\ No newline at end of file
diff --git a/src/vm/instruction.hh b/src/vm/instruction.hh
index 1710cdf..e87622a 100644
--- a/src/vm/instruction.hh
+++ b/src/vm/instruction.hh
@@ -2,6 +2,7 @@
 #define TYCHE_INSTRUCTION_HH
 
 #include <cstdint>
+#include <optional>
 #include <string>
 #include <utility>
 
@@ -9,6 +10,8 @@
 
 namespace tyche::vm {
 
+constexpr uint8_t OPCODE_NEXT_SIZE = 0x20;
+
 enum class Instruction : uint8_t {
 
     // stack operations
@@ -101,6 +104,8 @@ std::pair<std::string, size_t> debug_instruction(bc::Bytecode const& bt, uint32_
 enum class OperandType { NoOperand, Int8, Int16, Int32 };
 OperandType instruction_operand_type(Instruction instruction);
 
+std::optional<Instruction> translate_instruction(std::string const& txt, std::optional<int> op);
+
 }
 
 #endif //TYCHE_INSTRUCTION_HH