diff --git a/builtin-functions/kphp-light/stdlib/zlib-functions.txt b/builtin-functions/kphp-light/stdlib/zlib-functions.txt
index c340c48be7..2121dc2f37 100644
--- a/builtin-functions/kphp-light/stdlib/zlib-functions.txt
+++ b/builtin-functions/kphp-light/stdlib/zlib-functions.txt
@@ -6,23 +6,6 @@ define('ZLIB_ENCODING_RAW', -0x0f);
 define('ZLIB_ENCODING_DEFLATE', 0x0f);
 define('ZLIB_ENCODING_GZIP', 0x1f);
 
-function gzcompress ($str ::: string, $level ::: int = -1): string;
-
-function gzuncompress ($str ::: string): string;
-
-function gzencode ($str ::: string, $level ::: int = -1) ::: string;
-
-function gzdecode ($str ::: string) ::: string;
-
-function gzdeflate ($str ::: string, $level ::: int = -1) ::: string;
-
-function gzinflate ($str ::: string) ::: string;
-
-// ===== UNSUPPORTED =====
-
-/** @kphp-extern-func-info stub generation-required */
-function md5_file ($s ::: string, $raw_output ::: bool = false) ::: string | false;
-
 define('ZLIB_NO_FLUSH', 0);
 define('ZLIB_PARTIAL_FLUSH', 1);
 define('ZLIB_SYNC_FLUSH', 2);
@@ -37,15 +20,28 @@ define('ZLIB_RLE', 3);
 define('ZLIB_FIXED', 4);
 define('ZLIB_DEFAULT_STRATEGY', 0);
 
-/** @kphp-generate-stub-class */
+function gzcompress ($str ::: string, $level ::: int = -1): string;
+
+function gzuncompress ($str ::: string): string;
+
+function gzencode ($str ::: string, $level ::: int = -1) ::: string;
+
+function gzdecode ($str ::: string) ::: string;
+
+function gzdeflate ($str ::: string, $level ::: int = -1) ::: string;
+
+function gzinflate ($str ::: string) ::: string;
+
+function deflate_init(int $encoding, array $options = []) ::: ?DeflateContext;
+
+function deflate_add(DeflateContext $context, string $data, int $flush_mode = ZLIB_SYNC_FLUSH) ::: string | false;
+
 final class DeflateContext {
-    /** @kphp-extern-func-info stub generation-required */
     private function __construct() ::: DeflateContext;
 }
 
-// todo: deflate_init php signature has type array instead mixed
-/** @kphp-extern-func-info stub generation-required */
-function deflate_init(int $encoding, mixed $options = []) ::: ?DeflateContext;
-/** @kphp-extern-func-info stub generation-required */
-function deflate_add(DeflateContext $context, string $data, int $flush_mode = ZLIB_SYNC_FLUSH) ::: string | false;
 
+// ===== UNSUPPORTED =====
+
+/** @kphp-extern-func-info stub generation-required */
+function md5_file ($s ::: string, $raw_output ::: bool = false) ::: string | false;
diff --git a/runtime-light/stdlib/zlib/deflate-context.h b/runtime-light/stdlib/zlib/deflate-context.h
new file mode 100644
index 0000000000..4b030981d2
--- /dev/null
+++ b/runtime-light/stdlib/zlib/deflate-context.h
@@ -0,0 +1,26 @@
+// Compiler for PHP (aka KPHP)
+// Copyright (c) 2025 LLC «V Kontakte»
+// Distributed under the GPL v3 License, see LICENSE.notice.txt
+
+#pragma once
+
+#include "zlib/zlib.h"
+
+#include "runtime-common/core/class-instance/refcountable-php-classes.h"
+#include "runtime-common/stdlib/visitors/dummy-visitor-methods.h"
+
+struct C$DeflateContext : public refcountable_php_classes<C$DeflateContext>, private DummyVisitorMethods {
+  C$DeflateContext() noexcept = default;
+  using DummyVisitorMethods::accept;
+
+  C$DeflateContext(const C$DeflateContext&) = delete;
+  C$DeflateContext(C$DeflateContext&&) = delete;
+  C$DeflateContext& operator=(const C$DeflateContext&) = delete;
+  C$DeflateContext& operator=(C$DeflateContext&&) = delete;
+
+  ~C$DeflateContext() {
+    deflateEnd(std::addressof(stream));
+  }
+
+  z_stream stream{};
+};
diff --git a/runtime-light/stdlib/zlib/zlib-functions.cpp b/runtime-light/stdlib/zlib/zlib-functions.cpp
index d0783e0bee..45ac6d02b4 100644
--- a/runtime-light/stdlib/zlib/zlib-functions.cpp
+++ b/runtime-light/stdlib/zlib/zlib-functions.cpp
@@ -15,6 +15,7 @@
 #include "zlib/zlib.h"
 
 #include "common/containers/final_action.h"
+#include "runtime-common/core/allocator/script-malloc-interface.h"
 #include "runtime-common/core/runtime-core.h"
 #include "runtime-light/stdlib/diagnostics/logs.h"
 #include "runtime-light/stdlib/string/string-state.h"
@@ -36,6 +37,18 @@ voidpf zlib_static_alloc(voidpf opaque, uInt items, uInt size) noexcept {
 
 void zlib_static_free([[maybe_unused]] voidpf opaque, [[maybe_unused]] voidpf address) noexcept {}
 
+voidpf zlib_dynamic_alloc([[maybe_unused]] voidpf opaque, uInt items, uInt size) noexcept {
+  auto* mem{kphp::memory::script::calloc(items, size)};
+  if (mem == nullptr) [[unlikely]] {
+    kphp::log::warning("zlib dynamic alloc: can't allocate {} bytes", items * size);
+  }
+  return mem;
+}
+
+void zlib_dynamic_free([[maybe_unused]] voidpf opaque, voidpf address) noexcept {
+  kphp::memory::script::free(address);
+}
+
 } // namespace
 
 namespace kphp::zlib {
@@ -73,8 +86,7 @@ std::optional<string> encode(std::span<const char> data, int64_t level, int64_t
   zstrm.avail_out = out_size_upper_bound;
   zstrm.next_out = reinterpret_cast<Bytef*>(runtime_ctx.static_SB.buffer());
 
-  const auto deflate_res{deflate(std::addressof(zstrm), Z_FINISH)};
-  if (deflate_res != Z_STREAM_END) [[unlikely]] {
+  if (const auto deflate_res{deflate(std::addressof(zstrm), Z_FINISH)}; deflate_res != Z_STREAM_END) [[unlikely]] {
     kphp::log::warning("can't encode data of length {} due to zlib error {}", data.size(), deflate_res);
     return {};
   }
@@ -104,9 +116,8 @@ std::optional<string> decode(std::span<const char> data, int64_t encoding) noexc
   runtime_ctx.static_SB.clean().reserve(StringInstanceState::STATIC_BUFFER_LENGTH);
   zstrm.avail_out = StringInstanceState::STATIC_BUFFER_LENGTH;
   zstrm.next_out = reinterpret_cast<Bytef*>(runtime_ctx.static_SB.buffer());
-  const auto inflate_res{inflate(std::addressof(zstrm), Z_NO_FLUSH)};
 
-  if (inflate_res != Z_STREAM_END) [[unlikely]] {
+  if (const auto inflate_res{inflate(std::addressof(zstrm), Z_NO_FLUSH)}; inflate_res != Z_STREAM_END) [[unlikely]] {
     kphp::log::warning("can't decode data of length {} due to zlib error {}", data.size(), inflate_res);
     return {};
   }
@@ -115,3 +126,152 @@ std::optional<string> decode(std::span<const char> data, int64_t encoding) noexc
 }
 
 } // namespace kphp::zlib
+
+class_instance<C$DeflateContext> f$deflate_init(int64_t encoding, const array<mixed>& options) noexcept {
+  int32_t level{-1};
+  int32_t memory{8};
+  int32_t window{15};
+  auto strategy{Z_DEFAULT_STRATEGY};
+  constexpr auto extract_int_option{[](int32_t lbound, int32_t ubound, const array_iterator<const mixed>& option, int32_t& dst) noexcept {
+    if (const mixed & value{option.get_value()}; value.is_int() && value.as_int() >= lbound && value.as_int() <= ubound) {
+      dst = value.as_int();
+      return true;
+    } else {
+      kphp::log::warning("option {} should be number between {}..{}", option.get_string_key().c_str(), lbound, ubound);
+      return false;
+    }
+  }};
+
+  switch (encoding) {
+  case kphp::zlib::ENCODING_RAW:
+  case kphp::zlib::ENCODING_DEFLATE:
+  case kphp::zlib::ENCODING_GZIP:
+    break;
+  default:
+    kphp::log::warning("encoding should be one of ZLIB_ENCODING_RAW, ZLIB_ENCODING_DEFLATE, ZLIB_ENCODING_GZIP");
+    return {};
+  }
+
+  for (const auto& option : options) {
+    if (!option.is_string_key()) {
+      kphp::log::warning("unsupported option");
+      return {};
+    }
+
+    const auto& key{option.get_string_key()};
+    if (std::string_view{key.c_str(), key.size()} == "level") {
+      if (!extract_int_option(-1, 9, option, level)) {
+        return {};
+      }
+    } else if (std::string_view{key.c_str(), key.size()} == "memory") {
+      if (!extract_int_option(1, 9, option, memory)) {
+        return {};
+      }
+    } else if (std::string_view{key.c_str(), key.size()} == "window") {
+      if (!extract_int_option(8, 15, option, window)) {
+        return {};
+      }
+    } else if (std::string_view{key.c_str(), key.size()} == "strategy") {
+      if (mixed value{option.get_value()}; value.is_int()) {
+        switch (value.as_int()) {
+        case Z_FILTERED:
+        case Z_HUFFMAN_ONLY:
+        case Z_RLE:
+        case Z_FIXED:
+        case Z_DEFAULT_STRATEGY:
+          strategy = value.as_int();
+          break;
+        default:
+          kphp::log::warning("option strategy should be one of ZLIB_FILTERED, ZLIB_HUFFMAN_ONLY, ZLIB_RLE, ZLIB_FIXED or ZLIB_DEFAULT_STRATEGY");
+          return {};
+        }
+      } else {
+        kphp::log::warning("option strategy should be one of ZLIB_FILTERED, ZLIB_HUFFMAN_ONLY, ZLIB_RLE, ZLIB_FIXED or ZLIB_DEFAULT_STRATEGY");
+        return {};
+      }
+    } else if (std::string_view{key.c_str(), key.size()} == "dictionary") {
+      kphp::log::warning("option dictionary isn't supported yet");
+      return {};
+    } else {
+      kphp::log::warning("unknown option name \"{}\"", option.get_string_key().c_str());
+      return {};
+    }
+  }
+
+  class_instance<C$DeflateContext> context;
+  context.alloc();
+
+  z_stream* stream{std::addressof(context.get()->stream)};
+  stream->zalloc = zlib_dynamic_alloc;
+  stream->zfree = zlib_dynamic_free;
+  stream->opaque = nullptr;
+
+  if (encoding < 0) {
+    encoding += 15 - window;
+  } else {
+    encoding -= 15 - window;
+  }
+
+  if (auto err{deflateInit2(stream, level, Z_DEFLATED, encoding, memory, strategy)}; err != Z_OK) {
+    kphp::log::warning("zlib error {}", zError(err));
+    context.destroy();
+    return {};
+  }
+  return context;
+}
+
+Optional<string> f$deflate_add(const class_instance<C$DeflateContext>& context, const string& data, int64_t flush_type) noexcept {
+  constexpr uint64_t EXTRA_OUT_SIZE{30};
+  constexpr uint64_t MIN_OUT_SIZE{64};
+
+  switch (flush_type) {
+  case Z_BLOCK:
+  case Z_NO_FLUSH:
+  case Z_PARTIAL_FLUSH:
+  case Z_SYNC_FLUSH:
+  case Z_FULL_FLUSH:
+  case Z_FINISH:
+    break;
+  default:
+    kphp::log::warning("flush type should be one of ZLIB_NO_FLUSH, ZLIB_PARTIAL_FLUSH, ZLIB_SYNC_FLUSH, ZLIB_FULL_FLUSH, ZLIB_FINISH, ZLIB_BLOCK, ZLIB_TREES");
+    return {};
+  }
+
+  z_stream* stream{std::addressof(context.get()->stream)};
+  auto out_size{deflateBound(stream, data.size()) + EXTRA_OUT_SIZE};
+  out_size = out_size < MIN_OUT_SIZE ? MIN_OUT_SIZE : out_size;
+  string out{static_cast<string::size_type>(out_size), false};
+  stream->next_in = const_cast<Bytef*>(reinterpret_cast<const Bytef*>(data.c_str()));
+  stream->next_out = reinterpret_cast<Bytef*>(out.buffer());
+  stream->avail_in = data.size();
+  stream->avail_out = out_size;
+
+  auto status{Z_OK};
+  uint64_t buffer_used{};
+  do {
+    if (stream->avail_out == 0) {
+      out.reserve_at_least(out_size + MIN_OUT_SIZE);
+      out_size += MIN_OUT_SIZE;
+      stream->avail_out = MIN_OUT_SIZE;
+      stream->next_out = reinterpret_cast<Bytef*>(std::next(out.buffer(), buffer_used));
+    }
+    status = deflate(stream, flush_type);
+    buffer_used = out_size - stream->avail_out;
+  } while (status == Z_OK && stream->avail_out == 0);
+
+  std::ptrdiff_t len{};
+  switch (status) {
+  case Z_OK:
+    len = std::distance(reinterpret_cast<Bytef*>(out.buffer()), stream->next_out);
+    out.shrink(len);
+    return out;
+  case Z_STREAM_END:
+    len = std::distance(reinterpret_cast<Bytef*>(out.buffer()), stream->next_out);
+    deflateReset(stream);
+    out.shrink(len);
+    return out;
+  default:
+    kphp::log::warning("zlib error {}", zError(status));
+    return {};
+  }
+}
diff --git a/runtime-light/stdlib/zlib/zlib-functions.h b/runtime-light/stdlib/zlib/zlib-functions.h
index 968a141f36..3168e3d4af 100644
--- a/runtime-light/stdlib/zlib/zlib-functions.h
+++ b/runtime-light/stdlib/zlib/zlib-functions.h
@@ -10,6 +10,7 @@
 #include <span>
 
 #include "runtime-common/core/runtime-core.h"
+#include "runtime-light/stdlib/zlib/deflate-context.h"
 
 namespace kphp::zlib {
 
@@ -53,3 +54,7 @@ inline string f$gzdeflate(const string& data, int64_t level = kphp::zlib::MIN_CO
 inline string f$gzinflate(const string& data) noexcept {
   return kphp::zlib::decode({data.c_str(), static_cast<size_t>(data.size())}, kphp::zlib::ENCODING_RAW).value_or(string{});
 }
+
+class_instance<C$DeflateContext> f$deflate_init(int64_t encoding, const array<mixed>& options = {}) noexcept;
+
+Optional<string> f$deflate_add(const class_instance<C$DeflateContext>& context, const string& data, int64_t flush_type = Z_SYNC_FLUSH) noexcept;
diff --git a/tests/phpt/pk/016_gzip.php b/tests/phpt/pk/016_gzip.php
index 93e7c980a7..9032555ed8 100644
--- a/tests/phpt/pk/016_gzip.php
+++ b/tests/phpt/pk/016_gzip.php
@@ -1,4 +1,4 @@
-@ok k2_skip
+@ok
 <?php
 
 $x = "";