diff --git a/tests/libslic3r/CMakeLists.txt b/tests/libslic3r/CMakeLists.txt
index d5e6eb958e..5ced761fea 100644
--- a/tests/libslic3r/CMakeLists.txt
+++ b/tests/libslic3r/CMakeLists.txt
@@ -14,6 +14,7 @@ add_executable(${_TEST_NAME}_tests
     test_config.cpp
     test_preset_bundle_loading.cpp
     test_preset_setting_id.cpp
+    test_vendor_cache.cpp
     test_elephant_foot_compensation.cpp
     test_geometry.cpp
     test_placeholder_parser.cpp
diff --git a/tests/libslic3r/test_vendor_cache.cpp b/tests/libslic3r/test_vendor_cache.cpp
new file mode 100644
index 0000000000..78509f96ba
--- /dev/null
+++ b/tests/libslic3r/test_vendor_cache.cpp
@@ -0,0 +1,384 @@
+#include <catch2/catch_all.hpp>
+
+#include <boost/filesystem.hpp>
+#include <fstream>
+#include <set>
+
+#include "libslic3r/PresetBundle.hpp"
+#include "libslic3r/Preset.hpp"
+#include "libslic3r/PrintConfig.hpp"
+
+using namespace Slic3r;
+namespace fs = boost::filesystem;
+
+namespace {
+
+struct TempDir {
+    fs::path path;
+    TempDir() {
+        path = fs::temp_directory_path() / fs::unique_path("orca-cache-test-%%%%-%%%%");
+        fs::create_directories(path);
+    }
+    ~TempDir() { boost::system::error_code ec; fs::remove_all(path, ec); }
+};
+
+// Write a minimal vendor JSON with a version field so get_vendor_cache_key() returns
+// a deterministic Semver string rather than an mtime-based key.
+std::string write_vendor_json(const fs::path& dir, const std::string& vendor_id,
+                               const std::string& version = "1.0.0")
+{
+    const fs::path p = dir / (vendor_id + ".json");
+    std::ofstream f(p.string());
+    f << R"({"version":")" << version << R"(","name":")" << vendor_id << R"("})";
+    return p.string();
+}
+
+void add_vendor(PresetBundle& bundle, const std::string& vendor_id)
+{
+    VendorProfile vp(vendor_id);
+    vp.name           = vendor_id + " Corp";
+    vp.config_version = Semver(1, 0, 0);
+    bundle.vendors.emplace(vendor_id, vp);
+}
+
+Preset& add_system_preset(PresetCollection& coll, const std::string& name,
+                            const VendorProfile* vp)
+{
+    Preset& p = coll.load_preset("", name, DynamicPrintConfig(coll.default_preset().config), false);
+    p.is_system = true;
+    p.vendor    = vp;
+    return p;
+}
+
+} // namespace
+
+TEST_CASE("VendorCache: save and load via guide API", "[VendorCache]")
+{
+    TempDir           tmp;
+    const std::string vid       = "Acme";
+    const std::string json_path = write_vendor_json(tmp.path, vid);
+    const fs::path    cache     = tmp.path / (vid + ".cache");
+
+    PresetBundle src;
+    add_vendor(src, vid);
+    const VendorProfile* vp = &src.vendors.at(vid);
+
+    Preset& fp = add_system_preset(src.filaments, vid + " PLA @0.4", vp);
+    fp.alias       = "Acme PLA";
+    fp.filament_id = "GFL_acme_pla";
+
+    add_system_preset(src.printers, vid + " Printer 0.4", vp);
+
+    const auto stats = src.save_bundled_vendor_cache(vid, json_path, false, cache.string());
+    REQUIRE(stats.ok);
+    CHECK(stats.filament_presets == 1);
+    CHECK(stats.printer_presets  == 1);
+    CHECK(stats.print_presets    == 0);
+
+    VendorProfile       out_profile;
+    std::vector<Preset> out_printers, out_filaments, out_prints;
+    REQUIRE(PresetBundle::load_vendor_cache_for_guide(
+        cache.string(), get_vendor_cache_key(json_path),
+        out_profile, out_printers, out_filaments, out_prints));
+
+    CHECK(out_profile.id == vid);
+    REQUIRE(out_filaments.size() == 1);
+    CHECK(out_filaments[0].name        == vid + " PLA @0.4");
+    CHECK(out_filaments[0].alias       == "Acme PLA");
+    CHECK(out_filaments[0].filament_id == "GFL_acme_pla");
+    REQUIRE(out_printers.size() == 1);
+    CHECK(out_printers[0].name == vid + " Printer 0.4");
+}
+
+TEST_CASE("VendorCache: stale json_ver is rejected", "[VendorCache]")
+{
+    TempDir           tmp;
+    const std::string vid       = "Acme";
+    const std::string json_path = write_vendor_json(tmp.path, vid, "1.0.0");
+    const fs::path    cache     = tmp.path / (vid + ".cache");
+
+    PresetBundle src;
+    add_vendor(src, vid);
+    add_system_preset(src.filaments, vid + " PLA", &src.vendors.at(vid));
+    src.save_bundled_vendor_cache(vid, json_path, false, cache.string());
+
+    VendorProfile       p; std::vector<Preset> pr, fi, pp;
+    CHECK_FALSE(PresetBundle::load_vendor_cache_for_guide(cache.string(), "2.0.0", p, pr, fi, pp));
+}
+
+TEST_CASE("VendorCache: missing file returns false", "[VendorCache]")
+{
+    TempDir tmp;
+    VendorProfile       p; std::vector<Preset> pr, fi, pp;
+    CHECK_FALSE(PresetBundle::load_vendor_cache_for_guide(
+        (tmp.path / "nonexistent.cache").string(), "1.0.0", p, pr, fi, pp));
+}
+
+TEST_CASE("VendorCache: corrupt data is rejected by CRC check", "[VendorCache]")
+{
+    TempDir           tmp;
+    const std::string vid       = "Acme";
+    const std::string json_path = write_vendor_json(tmp.path, vid);
+    const fs::path    cache     = tmp.path / (vid + ".cache");
+
+    PresetBundle src;
+    add_vendor(src, vid);
+    add_system_preset(src.filaments, vid + " PLA", &src.vendors.at(vid));
+    src.save_bundled_vendor_cache(vid, json_path, false, cache.string());
+
+    // Flip a byte in the data region (after the 20-byte CacheFileHeader).
+    {
+        std::fstream f(cache.string(), std::ios::in | std::ios::out | std::ios::binary);
+        f.seekp(30);
+        char b; f.read(&b, 1);
+        f.seekp(30);
+        b ^= 0xFF;
+        f.write(&b, 1);
+    }
+
+    VendorProfile       p; std::vector<Preset> pr, fi, pp;
+    CHECK_FALSE(PresetBundle::load_vendor_cache_for_guide(
+        cache.string(), get_vendor_cache_key(json_path), p, pr, fi, pp));
+}
+
+TEST_CASE("VendorCache: multiple vendors do not bleed into each other", "[VendorCache]")
+{
+    TempDir tmp;
+    const std::string vid1 = "VendorA";
+    const std::string vid2 = "VendorB";
+
+    PresetBundle src;
+    const std::string json1 = write_vendor_json(tmp.path, vid1);
+    const std::string json2 = write_vendor_json(tmp.path, vid2);
+
+    for (const auto& vid : {vid1, vid2}) {
+        add_vendor(src, vid);
+        const VendorProfile* vp = &src.vendors.at(vid);
+        add_system_preset(src.filaments, vid + " PLA",     vp);
+        add_system_preset(src.printers,  vid + " Printer", vp);
+    }
+
+    src.save_bundled_vendor_cache(vid1, json1, false, (tmp.path / (vid1 + ".cache")).string());
+    src.save_bundled_vendor_cache(vid2, json2, false, (tmp.path / (vid2 + ".cache")).string());
+
+    for (const auto& [vid, jpath] : std::vector<std::pair<std::string, std::string>>{{vid1, json1}, {vid2, json2}}) {
+        VendorProfile       p; std::vector<Preset> pr, fi, pp;
+        REQUIRE(PresetBundle::load_vendor_cache_for_guide(
+            (tmp.path / (vid + ".cache")).string(), get_vendor_cache_key(jpath),
+            p, pr, fi, pp));
+        REQUIRE(fi.size() == 1);
+        CHECK(fi[0].name == vid + " PLA");
+        REQUIRE(pr.size() == 1);
+        CHECK(pr[0].name == vid + " Printer");
+    }
+}
+
+TEST_CASE("VendorCache: vendor profile fields are preserved", "[VendorCache]")
+{
+    TempDir           tmp;
+    const std::string vid       = "Acme";
+    const std::string json_path = write_vendor_json(tmp.path, vid, "2.5.1");
+    const fs::path    cache     = tmp.path / (vid + ".cache");
+
+    PresetBundle src;
+    VendorProfile vp(vid);
+    vp.name           = "Acme Corporation";
+    vp.config_version = Semver(2, 5, 1);
+    VendorProfile::PrinterModel model;
+    model.id   = "AcmePro";
+    model.name = "Acme Pro";
+    VendorProfile::PrinterVariant v0_4; v0_4.name = "0.4";
+    model.variants.push_back(v0_4);
+    vp.models.push_back(model);
+    src.vendors.emplace(vid, vp);
+
+    src.save_bundled_vendor_cache(vid, json_path, false, cache.string());
+
+    VendorProfile       out_p; std::vector<Preset> pr, fi, pp;
+    REQUIRE(PresetBundle::load_vendor_cache_for_guide(
+        cache.string(), get_vendor_cache_key(json_path), out_p, pr, fi, pp));
+
+    CHECK(out_p.id   == vid);
+    CHECK(out_p.name == "Acme Corporation");
+    REQUIRE(out_p.models.size() == 1);
+    CHECK(out_p.models[0].id   == "AcmePro");
+    CHECK(out_p.models[0].name == "Acme Pro");
+    REQUIRE(out_p.models[0].variants.size() == 1);
+    CHECK(out_p.models[0].variants[0].name  == "0.4");
+}
+
+TEST_CASE("VendorCache: config option values are preserved", "[VendorCache]")
+{
+    TempDir           tmp;
+    const std::string vid       = "Acme";
+    const std::string json_path = write_vendor_json(tmp.path, vid);
+    const fs::path    cache     = tmp.path / (vid + ".cache");
+
+    PresetBundle src;
+    add_vendor(src, vid);
+    const VendorProfile* vp = &src.vendors.at(vid);
+
+    Preset& fp = add_system_preset(src.filaments, vid + " PETG @0.4", vp);
+    fp.config.set_key_value("filament_type", new ConfigOptionStrings({"PETG"}));
+
+    src.save_bundled_vendor_cache(vid, json_path, false, cache.string());
+
+    VendorProfile       p; std::vector<Preset> pr, fi, pp;
+    REQUIRE(PresetBundle::load_vendor_cache_for_guide(
+        cache.string(), get_vendor_cache_key(json_path), p, pr, fi, pp));
+
+    REQUIRE(fi.size() == 1);
+    const auto* ft = fi[0].config.option<ConfigOptionStrings>("filament_type");
+    REQUIRE(ft != nullptr);
+    REQUIRE(ft->values.size() >= 1);
+    CHECK(ft->values[0] == "PETG");
+}
+
+TEST_CASE("VendorCache: multiple presets per collection round-trip", "[VendorCache]")
+{
+    TempDir           tmp;
+    const std::string vid       = "Acme";
+    const std::string json_path = write_vendor_json(tmp.path, vid);
+    const fs::path    cache     = tmp.path / (vid + ".cache");
+
+    PresetBundle src;
+    add_vendor(src, vid);
+    const VendorProfile* vp = &src.vendors.at(vid);
+
+    const std::vector<std::string> fi_names = {vid + " PLA", vid + " PETG", vid + " ABS"};
+    const std::vector<std::string> pr_names = {vid + " Printer 0.4", vid + " Printer 0.6"};
+
+    for (const auto& n : fi_names) add_system_preset(src.filaments, n, vp);
+    for (const auto& n : pr_names) add_system_preset(src.printers,  n, vp);
+
+    const auto stats = src.save_bundled_vendor_cache(vid, json_path, false, cache.string());
+    REQUIRE(stats.ok);
+    CHECK(stats.filament_presets == 3);
+    CHECK(stats.printer_presets  == 2);
+
+    VendorProfile       p; std::vector<Preset> pr, fi, pp;
+    REQUIRE(PresetBundle::load_vendor_cache_for_guide(
+        cache.string(), get_vendor_cache_key(json_path), p, pr, fi, pp));
+
+    REQUIRE(fi.size() == 3);
+    REQUIRE(pr.size() == 2);
+    std::set<std::string> fi_got, pr_got;
+    for (const auto& x : fi) fi_got.insert(x.name);
+    for (const auto& x : pr) pr_got.insert(x.name);
+    for (const auto& n : fi_names) CHECK(fi_got.count(n) == 1);
+    for (const auto& n : pr_names) CHECK(pr_got.count(n) == 1);
+}
+
+TEST_CASE("VendorCache: truncated file is rejected", "[VendorCache]")
+{
+    TempDir        tmp;
+    const fs::path cache = tmp.path / "truncated.cache";
+
+    // 3 bytes — shorter than the 20-byte CacheFileHeader
+    {
+        std::ofstream f(cache.string(), std::ios::binary);
+        const char data[] = {0x4F, 0x52, 0x43};
+        f.write(data, sizeof(data));
+    }
+
+    VendorProfile       p; std::vector<Preset> pr, fi, pp;
+    CHECK_FALSE(PresetBundle::load_vendor_cache_for_guide(
+        cache.string(), "1.0.0", p, pr, fi, pp));
+}
+
+TEST_CASE("VendorCache: wrong magic is rejected", "[VendorCache]")
+{
+    TempDir           tmp;
+    const std::string vid       = "Acme";
+    const std::string json_path = write_vendor_json(tmp.path, vid);
+    const fs::path    cache     = tmp.path / (vid + ".cache");
+
+    PresetBundle src;
+    add_vendor(src, vid);
+    add_system_preset(src.filaments, vid + " PLA", &src.vendors.at(vid));
+    src.save_bundled_vendor_cache(vid, json_path, false, cache.string());
+
+    // Overwrite first 4 bytes (magic field) with a wrong value; rest of file stays valid.
+    {
+        std::fstream f(cache.string(), std::ios::in | std::ios::out | std::ios::binary);
+        const uint32_t bad = 0xDEADBEEFu;
+        f.write(reinterpret_cast<const char*>(&bad), sizeof(bad));
+    }
+
+    VendorProfile       p; std::vector<Preset> pr, fi, pp;
+    CHECK_FALSE(PresetBundle::load_vendor_cache_for_guide(
+        cache.string(), get_vendor_cache_key(json_path), p, pr, fi, pp));
+}
+
+TEST_CASE("VendorCache: vendor with no presets saves and loads cleanly", "[VendorCache]")
+{
+    TempDir           tmp;
+    const std::string vid       = "Acme";
+    const std::string json_path = write_vendor_json(tmp.path, vid);
+    const fs::path    cache     = tmp.path / (vid + ".cache");
+
+    PresetBundle src;
+    VendorProfile vp(vid);
+    vp.name           = "Acme Corporation";
+    vp.config_version = Semver(1, 0, 0);
+    src.vendors.emplace(vid, vp);
+
+    const auto stats = src.save_bundled_vendor_cache(vid, json_path, false, cache.string());
+    REQUIRE(stats.ok);
+    CHECK(stats.print_presets    == 0);
+    CHECK(stats.filament_presets == 0);
+    CHECK(stats.printer_presets  == 0);
+
+    VendorProfile       p; std::vector<Preset> pr, fi, pp;
+    REQUIRE(PresetBundle::load_vendor_cache_for_guide(
+        cache.string(), get_vendor_cache_key(json_path), p, pr, fi, pp));
+    CHECK(p.id   == vid);
+    CHECK(p.name == "Acme Corporation");
+    CHECK(fi.empty());
+    CHECK(pr.empty());
+    CHECK(pp.empty());
+}
+
+TEST_CASE("VendorCache: all Preset metadata fields are preserved", "[VendorCache]")
+{
+    TempDir           tmp;
+    const std::string vid       = "Acme";
+    const std::string json_path = write_vendor_json(tmp.path, vid);
+    const fs::path    cache     = tmp.path / (vid + ".cache");
+
+    PresetBundle src;
+    add_vendor(src, vid);
+    const VendorProfile* vp = &src.vendors.at(vid);
+
+    Preset& fp          = add_system_preset(src.filaments, vid + " PLA @0.4", vp);
+    fp.setting_id       = "sid-test-001";
+    fp.description      = "A test filament preset";
+    fp.bundle_id        = "bundle-xyz";
+    fp.user_id          = "user-abc";
+    fp.base_id          = "base-123";
+    fp.sync_info        = "update";
+    fp.updated_time     = 1700000000LL;
+    fp.key_values       = {{"color", "red"}, {"diameter", "1.75"}};
+    fp.ini_str          = "[filament]\nnozzle_temperature = 230\n";
+
+    src.save_bundled_vendor_cache(vid, json_path, false, cache.string());
+
+    VendorProfile       p; std::vector<Preset> pr, fi, pp;
+    REQUIRE(PresetBundle::load_vendor_cache_for_guide(
+        cache.string(), get_vendor_cache_key(json_path), p, pr, fi, pp));
+
+    REQUIRE(fi.size() == 1);
+    const Preset& out = fi[0];
+    CHECK(out.setting_id   == "sid-test-001");
+    CHECK(out.description  == "A test filament preset");
+    CHECK(out.bundle_id    == "bundle-xyz");
+    CHECK(out.user_id      == "user-abc");
+    CHECK(out.base_id      == "base-123");
+    CHECK(out.sync_info    == "update");
+    CHECK(out.updated_time == 1700000000LL);
+    REQUIRE(out.key_values.count("color") == 1);
+    CHECK(out.key_values.at("color")      == "red");
+    REQUIRE(out.key_values.count("diameter") == 1);
+    CHECK(out.key_values.at("diameter")   == "1.75");
+    CHECK(out.ini_str == "[filament]\nnozzle_temperature = 230\n");
+}