diff --git a/apps/web/src/components/ui/Filter.tsx b/apps/web/src/components/ui/Filter.tsx
index b091b813..0df55016 100644
--- a/apps/web/src/components/ui/Filter.tsx
+++ b/apps/web/src/components/ui/Filter.tsx
@@ -1,7 +1,7 @@
 "use client";
 
 import { AccordionContent, AccordionItem, AccordionTrigger } from "./accordion";
-import { RadioGroup, RadioGroupItem } from "@/components/ui/radio-group";
+import { Checkbox } from "@/components/ui/checkbox";
 import { Label } from "@/components/ui/label";
 import { useFilterInputStore } from "@/store/useFilterInputStore";
 import clsx from "clsx";
@@ -15,12 +15,8 @@ export default function Filter({
   filters: string[];
   onClick?: () => void;
 }) {
-  const { updateFilters } = useFilterInputStore();
-  const inputData: { [key: string]: string } = {};
-  const recordFilterInput = (filter: string) => {
-    inputData[filterName] = filter;
-    updateFilters(inputData);
-  };
+  const { filters: selectedFilters, toggleFilter } = useFilterInputStore();
+  const selectedValues = selectedFilters[filterName] || [];
 
   const triggerClasses = clsx("text-sm font-medium", {
     "text-slate-300": ["Hire contributors", "Funding", "Trending"].includes(
@@ -35,25 +31,24 @@ export default function Filter({
           <span className="text-sm font-medium text-white">{filterName}</span>
         </AccordionTrigger>
         <AccordionContent className="pt-1 pb-3">
-          <RadioGroup className="space-y-3">
+          <div className="space-y-3">
             {filters.map((filter) => (
               <div key={filter} className="flex items-center space-x-3">
-                <RadioGroupItem
-                  value={filter}
-                  id={filter}
-                  onClick={() => recordFilterInput(filter)}
-                  className="border-[#28282c] bg-[#141418] text-ox-purple transition data-[state=checked]:border-ox-purple data-[state=checked]:bg-ox-purple/20 data-[state=checked]:ring-2 data-[state=checked]:ring-ox-purple/50"
+                <Checkbox
+                  id={`${filterName}-${filter}`}
+                  checked={selectedValues.includes(filter)}
+                  onCheckedChange={() => toggleFilter(filterName, filter)}
+                  className="border-[#28282c] bg-[#141418] transition data-[state=checked]:border-ox-purple data-[state=checked]:bg-ox-purple data-[state=checked]:text-white"
                 />
                 <Label
-                  htmlFor={filter}
-                  onClick={() => recordFilterInput(filter)}
+                  htmlFor={`${filterName}-${filter}`}
                   className="text-sm text-zinc-300 cursor-pointer transition-colors"
                 >
                   {filter}
                 </Label>
               </div>
             ))}
-          </RadioGroup>
+          </div>
         </AccordionContent>
       </AccordionItem>
     </div>
diff --git a/apps/web/src/store/useFilterInputStore.ts b/apps/web/src/store/useFilterInputStore.ts
index 927eb80e..62414715 100644
--- a/apps/web/src/store/useFilterInputStore.ts
+++ b/apps/web/src/store/useFilterInputStore.ts
@@ -1,16 +1,22 @@
 import { create } from "zustand";
 
 interface FilterInputState {
-  filters: object;
-  updateFilters: (newFilter: Record<string, string>) => void;
+  filters: Record<string, string[]>;
+  toggleFilter: (filterName: string, value: string) => void;
   resetFilters: () => void;
 }
 
 export const useFilterInputStore = create<FilterInputState>((set) => ({
   filters: {},
-  updateFilters: (newFilter) =>
-    set((state) => ({
-      filters: { ...state.filters, ...newFilter },
-    })),
+  toggleFilter: (filterName, value) =>
+    set((state) => {
+      const currentValues = state.filters[filterName] || [];
+      const newValues = currentValues.includes(value)
+        ? currentValues.filter((v) => v !== value)
+        : [...currentValues, value];
+      return {
+        filters: { ...state.filters, [filterName]: newValues },
+      };
+    }),
   resetFilters: () => set({ filters: {} }),
 }));
diff --git a/apps/web/src/types/filter.ts b/apps/web/src/types/filter.ts
index db245af3..f00bb2c6 100644
--- a/apps/web/src/types/filter.ts
+++ b/apps/web/src/types/filter.ts
@@ -48,9 +48,9 @@ export type ProjectProps = {
 };
 
 export type UserInputFilterProps = {
-  "Tech stack"?: string;
-  Popularity?: string;
-  Competition?: string;
-  Stage?: string;
-  Activity?: string;
+  "Tech stack"?: string[];
+  Popularity?: string[];
+  Competition?: string[];
+  Stage?: string[];
+  Activity?: string[];
 };
diff --git a/apps/web/src/utils/converter.ts b/apps/web/src/utils/converter.ts
index 53a5c793..50ec37fa 100644
--- a/apps/web/src/utils/converter.ts
+++ b/apps/web/src/utils/converter.ts
@@ -111,27 +111,62 @@ export const convertUserInputToApiInput = (
 ): FilterProps => {
   const data: Partial<FilterProps> = {};
 
-  if (filter["Tech stack"]) {
-    data.language = filter["Tech stack"];
+  // Handle multiple tech stacks - join with comma for API
+  if (filter["Tech stack"] && filter["Tech stack"].length > 0) {
+    data.language = filter["Tech stack"].join(",");
   }
 
-  if (filter.Popularity) {
-    data.stars =
-      userInputValues.Popularity[filter.Popularity as keyof PopularityProps];
+  // Handle multiple popularity values - merge ranges (min of mins, max of maxes)
+  if (filter.Popularity && filter.Popularity.length > 0) {
+    const ranges = filter.Popularity.map(
+      (p) => userInputValues.Popularity[p as keyof PopularityProps]
+    ).filter(Boolean);
+    if (ranges.length > 0) {
+      const mins = ranges.map((r) => parseInt(r.min || "0", 10));
+      const maxes = ranges.map((r) => (r.max ? parseInt(r.max, 10) : Infinity));
+      data.stars = {
+        min: String(Math.min(...mins)),
+        ...(Math.max(...maxes) !== Infinity && { max: String(Math.max(...maxes)) }),
+      };
+    }
   }
 
-  if (filter.Competition) {
-    data.forks =
-      userInputValues.Competition[filter.Competition as keyof CompetitionProps];
+  // Handle multiple competition values - merge ranges
+  if (filter.Competition && filter.Competition.length > 0) {
+    const ranges = filter.Competition.map(
+      (c) => userInputValues.Competition[c as keyof CompetitionProps]
+    ).filter(Boolean);
+    if (ranges.length > 0) {
+      const mins = ranges.map((r) => parseInt(r.min || "0", 10));
+      const maxes = ranges.map((r) => (r.max ? parseInt(r.max, 10) : Infinity));
+      data.forks = {
+        min: String(Math.min(...mins)),
+        ...(Math.max(...maxes) !== Infinity && { max: String(Math.max(...maxes)) }),
+      };
+    }
   }
 
-  if (filter.Activity) {
-    data.pushed =
-      userInputValues.Activity[filter.Activity as keyof ActivityProps];
+  // Handle multiple activity values - use the most recent date (broadest range)
+  if (filter.Activity && filter.Activity.length > 0) {
+    const dates = filter.Activity.map(
+      (a) => userInputValues.Activity[a as keyof ActivityProps]
+    ).filter(Boolean);
+    if (dates.length > 0) {
+      // Find the oldest date (most inclusive)
+      const oldestDate = dates.sort()[0];
+      data.pushed = oldestDate;
+    }
   }
 
-  if (filter.Stage) {
-    data.created = userInputValues.Stage[filter.Stage as keyof StageProps];
+  // Handle multiple stage values - use the oldest date (most inclusive)
+  if (filter.Stage && filter.Stage.length > 0) {
+    const dates = filter.Stage.map(
+      (s) => userInputValues.Stage[s as keyof StageProps]
+    ).filter(Boolean);
+    if (dates.length > 0) {
+      const oldestDate = dates.sort()[0];
+      data.created = oldestDate;
+    }
   }
 
   return data as FilterProps;
@@ -149,10 +184,10 @@ export const convertApiOutputToUserOutput = (
     avatarUrl: item.owner.avatarUrl,
     totalIssueCount: item.issues.totalCount,
     primaryLanguage: item.primaryLanguage?.name || "Other",
-    popularity: filters.Popularity ? filters.Popularity : "-",
-    stage: filters.Stage ? filters.Stage : "-",
-    competition: filters.Competition ? filters.Competition : "-",
-    activity: filters.Activity ? filters.Activity : "-",
+    popularity: filters.Popularity?.join(", ") || "-",
+    stage: filters.Stage?.join(", ") || "-",
+    competition: filters.Competition?.join(", ") || "-",
+    activity: filters.Activity?.join(", ") || "-",
   }));
   return data;
 };