diff --git a/src/location/GeoCache.zig b/src/location/GeoCache.zig
index 958f9ec..7180182 100644
--- a/src/location/GeoCache.zig
+++ b/src/location/GeoCache.zig
@@ -88,6 +88,34 @@ pub fn saveIfNeeded(self: *GeoCache) void {
     self.last_save = now;
 }
 
+fn load(allocator: std.mem.Allocator, cache: *std.StringHashMap(CachedLocation), content: []const u8) !void {
+    const CacheData = struct {
+        name: []const u8,
+        latitude: f64,
+        longitude: f64,
+    };
+
+    const parsed = try std.json.parseFromSlice(
+        std.json.ArrayHashMap(CacheData),
+        allocator,
+        content,
+        .{},
+    );
+    defer parsed.deinit();
+
+    for (parsed.value.map.keys(), parsed.value.map.values()) |key, value| {
+        const cache_key = try allocator.dupe(u8, key);
+        const cache_value = CachedLocation{
+            .name = try allocator.dupe(u8, value.name),
+            .coords = .{
+                .latitude = value.latitude,
+                .longitude = value.longitude,
+            },
+        };
+        try cache.put(cache_key, cache_value);
+    }
+}
+
 fn loadFromFile(allocator: std.mem.Allocator, cache: *std.StringHashMap(CachedLocation), file_path: []const u8) !void {
     const file = try std.fs.cwd().openFile(file_path, .{});
     defer file.close();
@@ -95,37 +123,10 @@ fn loadFromFile(allocator: std.mem.Allocator, cache: *std.StringHashMap(CachedLo
     const content = try file.readToEndAlloc(allocator, 10 * 1024 * 1024); // 10MB max
     defer allocator.free(content);
 
-    const parsed = try std.json.parseFromSlice(
-        std.json.Value,
-        allocator,
-        content,
-        .{},
-    );
-    defer parsed.deinit();
-
-    var it = parsed.value.object.iterator();
-    while (it.next()) |entry| {
-        const obj = entry.value_ptr.object;
-        const key = try allocator.dupe(u8, entry.key_ptr.*);
-        const value = CachedLocation{
-            .name = try allocator.dupe(u8, obj.get("name").?.string),
-            .coords = .{
-                .latitude = obj.get("latitude").?.float,
-                .longitude = obj.get("longitude").?.float,
-            },
-        };
-        try cache.put(key, value);
-    }
+    try load(allocator, cache, content);
 }
 
-fn saveToFile(self: *GeoCache, file_path: []const u8) !void {
-    const file = try std.fs.cwd().createFile(file_path, .{});
-    defer file.close();
-
-    var buffer: [4096]u8 = undefined;
-    var file_writer = file.writer(&buffer);
-    const writer = &file_writer.interface;
-
+fn save(self: *GeoCache, writer: *std.Io.Writer) !void {
     try writer.writeAll("{\n");
 
     var it = self.cache.iterator();
@@ -134,7 +135,7 @@ fn saveToFile(self: *GeoCache, file_path: []const u8) !void {
         if (!first) try writer.writeAll(",\n");
         first = false;
 
-        try writer.print("  {any}: {any}", .{
+        try writer.print("  {f}: {f}", .{
             std.json.fmt(entry.key_ptr.*, .{}),
             std.json.fmt(.{
                 .name = entry.value_ptr.name,
@@ -145,6 +146,17 @@ fn saveToFile(self: *GeoCache, file_path: []const u8) !void {
     }
 
     try writer.writeAll("\n}\n");
+}
+
+fn saveToFile(self: *GeoCache, file_path: []const u8) !void {
+    const file = try std.fs.cwd().createFile(file_path, .{});
+    defer file.close();
+
+    var buffer: [4096]u8 = undefined;
+    var file_writer = file.writer(&buffer);
+    const writer = &file_writer.interface;
+
+    try self.save(writer);
     try writer.flush();
 }
 
@@ -176,3 +188,90 @@ test "GeoCache miss returns null" {
     const result = cache.get("NonExistent");
     try std.testing.expect(result == null);
 }
+
+test "save produces valid JSON" {
+    const allocator = std.testing.allocator;
+    var cache = try GeoCache.init(allocator, null);
+    defer cache.deinit();
+
+    try cache.put("London", .{
+        .name = "London, UK",
+        .coords = .{ .latitude = 51.5074, .longitude = -0.1278 },
+    });
+    try cache.put("Paris", .{
+        .name = "Paris, France",
+        .coords = .{ .latitude = 48.8566, .longitude = 2.3522 },
+    });
+
+    var buffer: [1024]u8 = undefined;
+    var writer = std.Io.Writer.fixed(&buffer);
+    try cache.save(&writer);
+
+    const output = buffer[0..writer.end];
+    try std.testing.expect(std.mem.indexOf(u8, output, "London") != null);
+    try std.testing.expect(std.mem.indexOf(u8, output, "Paris") != null);
+    try std.testing.expect(std.mem.indexOf(u8, output, "51.5074") != null);
+}
+
+test "load parses valid JSON" {
+    const allocator = std.testing.allocator;
+    var cache_map = std.StringHashMap(CachedLocation).init(allocator);
+    defer {
+        var it = cache_map.iterator();
+        while (it.next()) |entry| {
+            allocator.free(entry.key_ptr.*);
+            allocator.free(entry.value_ptr.name);
+        }
+        cache_map.deinit();
+    }
+
+    const json =
+        \\{
+        \\  "London": {"name": "London, UK", "latitude": 51.5074, "longitude": -0.1278},
+        \\  "Paris": {"name": "Paris, France", "latitude": 48.8566, "longitude": 2.3522}
+        \\}
+    ;
+
+    try load(allocator, &cache_map, json);
+
+    const london = cache_map.get("London");
+    try std.testing.expect(london != null);
+    try std.testing.expectApproxEqAbs(@as(f64, 51.5074), london.?.coords.latitude, 0.0001);
+
+    const paris = cache_map.get("Paris");
+    try std.testing.expect(paris != null);
+    try std.testing.expectApproxEqAbs(@as(f64, 48.8566), paris.?.coords.latitude, 0.0001);
+}
+
+test "save and load round-trip" {
+    const allocator = std.testing.allocator;
+    var cache1 = try GeoCache.init(allocator, null);
+    defer cache1.deinit();
+
+    try cache1.put("Berlin", .{
+        .name = "Berlin, Germany",
+        .coords = .{ .latitude = 52.5200, .longitude = 13.4050 },
+    });
+
+    var buffer: [1024]u8 = undefined;
+    var writer = std.Io.Writer.fixed(&buffer);
+    try cache1.save(&writer);
+
+    var cache2 = std.StringHashMap(CachedLocation).init(allocator);
+    defer {
+        var it = cache2.iterator();
+        while (it.next()) |entry| {
+            allocator.free(entry.key_ptr.*);
+            allocator.free(entry.value_ptr.name);
+        }
+        cache2.deinit();
+    }
+
+    try load(allocator, &cache2, buffer[0..writer.end]);
+
+    const berlin = cache2.get("Berlin");
+    try std.testing.expect(berlin != null);
+    try std.testing.expectEqualStrings("Berlin, Germany", berlin.?.name);
+    try std.testing.expectApproxEqAbs(@as(f64, 52.5200), berlin.?.coords.latitude, 0.0001);
+    try std.testing.expectApproxEqAbs(@as(f64, 13.4050), berlin.?.coords.longitude, 0.0001);
+}