diff --git a/src/app/api/applications/route.ts b/src/app/api/applications/route.ts
index 51f0dcc4..7c5d2ef7 100644
--- a/src/app/api/applications/route.ts
+++ b/src/app/api/applications/route.ts
@@ -46,7 +46,7 @@ export async function POST(request: NextRequest) {
       .from("gigs")
       .select("poster_id, status, title, poster:profiles!poster_id(full_name, username)")
       .eq("id", gig_id)
-      .single();
+      .maybeSingle();
 
     if (!gig) {
       return NextResponse.json({ error: "Gig not found" }, { status: 404 });
@@ -76,7 +76,7 @@ export async function POST(request: NextRequest) {
       .select("id")
       .eq("gig_id", gig_id)
       .eq("applicant_id", user.id)
-      .single();
+      .maybeSingle();
 
     if (existingApplication) {
       return NextResponse.json(
@@ -94,7 +94,7 @@ export async function POST(request: NextRequest) {
         ...applicationData,
       })
       .select()
-      .single();
+      .maybeSingle();
 
     if (error) {
       return NextResponse.json({ error: error.message }, { status: 400 });
@@ -121,7 +121,7 @@ export async function POST(request: NextRequest) {
         .from("profiles")
         .select("full_name, username")
         .eq("id", user.id)
-        .single();
+        .maybeSingle();
 
       const applicantName = applicantProfile?.full_name || applicantProfile?.username || "A candidate";
       const posterName = poster?.full_name || poster?.username || "there";
diff --git a/src/app/api/conversations/route.ts b/src/app/api/conversations/route.ts
index d1c8d2bf..e45099df 100644
--- a/src/app/api/conversations/route.ts
+++ b/src/app/api/conversations/route.ts
@@ -140,7 +140,7 @@ export async function POST(request: NextRequest) {
       .from("profiles")
       .select("id")
       .eq("id", recipient_id)
-      .single();
+      .maybeSingle();
 
     if (!recipient) {
       return NextResponse.json(
@@ -159,7 +159,7 @@ export async function POST(request: NextRequest) {
         .from("gigs")
         .select("id, poster_id")
         .eq("id", gig_id)
-        .single();
+        .maybeSingle();
 
       if (!gig) {
         return NextResponse.json({ error: "Gig not found" }, { status: 404 });
@@ -175,7 +175,7 @@ export async function POST(request: NextRequest) {
           .select("id")
           .eq("gig_id", gig_id)
           .eq("applicant_id", user.id)
-          .single();
+          .maybeSingle();
 
         isApplicant = !!application;
       }
@@ -193,7 +193,7 @@ export async function POST(request: NextRequest) {
         .select("*")
         .eq("gig_id", gig_id)
         .contains("participant_ids", participantIds)
-        .single();
+        .maybeSingle();
 
       if (existingConv) {
         return NextResponse.json({ data: existingConv });
@@ -207,7 +207,7 @@ export async function POST(request: NextRequest) {
           gig_id,
         })
         .select()
-        .single();
+        .maybeSingle();
 
       if (error) {
         return NextResponse.json({ error: error.message }, { status: 400 });
@@ -236,7 +236,7 @@ export async function POST(request: NextRequest) {
           gig_id: null,
         })
         .select()
-        .single();
+        .maybeSingle();
 
       if (error) {
         return NextResponse.json({ error: error.message }, { status: 400 });
@@ -277,7 +277,7 @@ export async function PATCH(request: NextRequest) {
       .select("id, participant_ids")
       .eq("id", conversation_id)
       .contains("participant_ids", [user.id])
-      .single();
+      .maybeSingle();
 
     if (!conv) {
       return NextResponse.json(
@@ -293,7 +293,7 @@ export async function PATCH(request: NextRequest) {
       })
       .eq("id", conversation_id)
       .select()
-      .single();
+      .maybeSingle();
 
     if (error) {
       return NextResponse.json({ error: error.message }, { status: 400 });
diff --git a/src/app/api/gigs/route.ts b/src/app/api/gigs/route.ts
index cd218842..17e782e9 100644
--- a/src/app/api/gigs/route.ts
+++ b/src/app/api/gigs/route.ts
@@ -73,7 +73,7 @@ export async function GET(request: NextRequest) {
       )
       .eq("status", "active");
 
-    // Apply filters — use textSearch or individual filters to prevent PostgREST filter injection (#71)
+    // Apply filters �use textSearch or individual filters to prevent PostgREST filter injection (#71)
     if (search) {
       // Sanitize: escape PostgREST special chars and SQL wildcards
       const safeSearch = search
@@ -113,7 +113,7 @@ export async function GET(request: NextRequest) {
 
     // Default to 'hiring' unless explicitly requesting for_hire or 'all'
     if (listing_type === "all") {
-      // No filter — return both types
+      // No filter �return both types
     } else if (listing_type) {
       query = query.eq("listing_type", listing_type);
     } else {
@@ -139,7 +139,7 @@ export async function GET(request: NextRequest) {
         query = query.order("created_at", { ascending: false });
     }
 
-    // Apply pagination — ensure non-negative offset (#69)
+    // Apply pagination �ensure non-negative offset (#69)
     const offset = Math.max(0, (page - 1) * limit);
     query = query.range(offset, offset + limit - 1);
 
@@ -222,7 +222,7 @@ export async function POST(request: NextRequest) {
         .from("subscriptions")
         .select("plan")
         .eq("user_id", user.id)
-        .single();
+        .maybeSingle();
 
       if (!subscription || subscription.plan === "free") {
         const { data: usage } = await supabase
@@ -231,7 +231,7 @@ export async function POST(request: NextRequest) {
           .eq("user_id", user.id)
           .eq("month", month)
           .eq("year", year)
-          .single();
+          .maybeSingle();
 
         if (usage && usage.posts_count >= 10) {
           return NextResponse.json(
@@ -254,7 +254,7 @@ export async function POST(request: NextRequest) {
         ...validationResult.data,
       })
       .select()
-      .single();
+      .maybeSingle();
 
     if (error) {
       return NextResponse.json({ error: error.message }, { status: 400 });
diff --git a/src/app/api/messages/send/route.ts b/src/app/api/messages/send/route.ts
index 5bb068fa..52ced6bf 100644
--- a/src/app/api/messages/send/route.ts
+++ b/src/app/api/messages/send/route.ts
@@ -43,7 +43,7 @@ export async function POST(request: NextRequest) {
       .from("profiles")
       .select("id, full_name, username, last_active_at")
       .eq("username", recipient)
-      .single();
+      .maybeSingle();
 
     if (recipientError || !recipientProfile) {
       return NextResponse.json(
@@ -67,7 +67,7 @@ export async function POST(request: NextRequest) {
       .select("id, participant_ids")
       .is("gig_id", null)
       .contains("participant_ids", participantIds)
-      .single();
+      .maybeSingle();
 
     let conversationId: string;
 
@@ -82,7 +82,7 @@ export async function POST(request: NextRequest) {
           gig_id: null,
         })
         .select("id")
-        .single();
+        .maybeSingle();
 
       if (createError || !newConversation) {
         return NextResponse.json(
@@ -114,7 +114,7 @@ export async function POST(request: NextRequest) {
         )
       `
       )
-      .single();
+      .maybeSingle();
 
     if (messageError || !message) {
       return NextResponse.json(
@@ -134,7 +134,7 @@ export async function POST(request: NextRequest) {
       .from("profiles")
       .select("full_name, username")
       .eq("id", user.id)
-      .single();
+      .maybeSingle();
 
     const senderName =
       senderProfile?.full_name || senderProfile?.username || "Someone";
diff --git a/src/app/api/profile/route.ts b/src/app/api/profile/route.ts
index e7b030c4..253f71ea 100644
--- a/src/app/api/profile/route.ts
+++ b/src/app/api/profile/route.ts
@@ -18,9 +18,9 @@ export async function GET(request: NextRequest) {
       .from("profiles")
       .select("*")
       .eq("id", user.id)
-      .single();
+      .maybeSingle();
 
-    if (error) {
+    if (error || !profile) {
       return NextResponse.json({ error: error.message }, { status: 400 });
     }
 
@@ -100,7 +100,7 @@ export async function PUT(request: NextRequest) {
       .from("profiles")
       .select("did, resume_url")
       .eq("id", user.id)
-      .single();
+      .maybeSingle();
 
     // Check if profile is complete
     const isComplete = Boolean(
@@ -120,9 +120,9 @@ export async function PUT(request: NextRequest) {
       .update(updateData)
       .eq("id", user.id)
       .select()
-      .single();
+      .maybeSingle();
 
-    if (error) {
+    if (error || !profile) {
       console.error("Profile update error:", error);
       console.error("Error details:", JSON.stringify(error, null, 2));
       return NextResponse.json({ error: error.message }, { status: 400 });