diff --git a/miniapp/assets/assembly.js b/miniapp/assets/assembly.js
index 94c2e00..d715af1 100644
--- a/miniapp/assets/assembly.js
+++ b/miniapp/assets/assembly.js
@@ -21,7 +21,7 @@ const Assembly = (function () {
     const ctrl = new AbortController();
     const timer = setTimeout(() => ctrl.abort(), timeoutMs);
     try {
-      const res = await fetch(url, { method: "POST", signal: ctrl.signal, body: JSON.stringify(body) });
+      const res = await fetch(url, { method: "POST", signal: ctrl.signal, headers: { "Content-Type": "application/json" }, body: JSON.stringify(body) });
       return await res.json();
     } catch (e) {
       if (e.name === "AbortError") throw new Error("Сервер не отвечает — попробуйте ещё раз");
diff --git a/miniapp/assets/inbox.js b/miniapp/assets/inbox.js
index fb9f48c..0f57255 100644
--- a/miniapp/assets/inbox.js
+++ b/miniapp/assets/inbox.js
@@ -24,6 +24,7 @@ const InboxScreen = (function () {
     try {
       const res = await fetch(`${BACKEND_URL}/api/${path}`, {
         method: "POST", signal: ctrl.signal,
+        headers: { "Content-Type": "application/json" },
         body: JSON.stringify({ initData: tg?.initData || "", initDataUnsafe: tg?.initDataUnsafe || null, ...body }),
       });
       return await res.json();
diff --git a/miniapp/assets/me.js b/miniapp/assets/me.js
index a6303e7..a010e17 100644
--- a/miniapp/assets/me.js
+++ b/miniapp/assets/me.js
@@ -15,7 +15,7 @@ const MeScreen = (function () {
     const ctrl = new AbortController();
     const t = setTimeout(() => ctrl.abort(), ms);
     try {
-      const res = await fetch(url, { method: "POST", signal: ctrl.signal, body: JSON.stringify(body) });
+      const res = await fetch(url, { method: "POST", signal: ctrl.signal, headers: { "Content-Type": "application/json" }, body: JSON.stringify(body) });
       return await res.json();
     } catch (e) {
       if (e.name === "AbortError") throw new Error("Сервер не отвечает");
diff --git a/miniapp/assets/measurements.js b/miniapp/assets/measurements.js
index 2f99d70..d41e79e 100644
--- a/miniapp/assets/measurements.js
+++ b/miniapp/assets/measurements.js
@@ -98,7 +98,7 @@ const Measurements = (function () {
     const ctrl = new AbortController();
     const timer = setTimeout(() => ctrl.abort(), timeoutMs);
     try {
-      const res = await fetch(url, { method: "POST", signal: ctrl.signal, body: JSON.stringify(body) });
+      const res = await fetch(url, { method: "POST", signal: ctrl.signal, headers: { "Content-Type": "application/json" }, body: JSON.stringify(body) });
       return await res.json();
     } catch (e) {
       if (e.name === "AbortError") throw new Error("Сервер не отвечает — попробуйте ещё раз");
diff --git a/miniapp/assets/proposals.js b/miniapp/assets/proposals.js
index b9efa33..8bcfe4e 100644
--- a/miniapp/assets/proposals.js
+++ b/miniapp/assets/proposals.js
@@ -26,6 +26,7 @@ const Proposals = (function () {
       const res = await fetch(`${BACKEND_URL}/api/${path}`, {
         method: "POST",
         signal: ctrl.signal,
+        headers: { "Content-Type": "application/json" },
         body: JSON.stringify({ ...authBody(), ...extra }),
       });
       if (!res.ok) throw new Error("HTTP " + res.status);
diff --git a/miniapp/assets/request.js b/miniapp/assets/request.js
index 046d76c..05981df 100644
--- a/miniapp/assets/request.js
+++ b/miniapp/assets/request.js
@@ -19,7 +19,7 @@ const MeasurementRequest = (function () {
     const ctrl = new AbortController();
     const timer = setTimeout(() => ctrl.abort(), timeoutMs);
     try {
-      const res = await fetch(url, { method: "POST", signal: ctrl.signal, body: JSON.stringify(body) });
+      const res = await fetch(url, { method: "POST", signal: ctrl.signal, headers: { "Content-Type": "application/json" }, body: JSON.stringify(body) });
       return await res.json();
     } catch (e) {
       if (e.name === "AbortError") throw new Error("Сервер не отвечает — попробуйте ещё раз");