diff --git a/app.js b/app.js
index 1ae44dc..16ab83e 100644
--- a/app.js
+++ b/app.js
@@ -872,7 +872,7 @@ function renderKeys(keys) {
             </div>
             <button type="button" class="btn btn-ghost btn-sm"
                     style="align-self:center"
-                    onclick="buyCredits('${escAttr(k.name)}', this)">
+                    onclick="buyCredits('${escAttr(k.name)}')">
                 Buy Credits
             </button>
         </div>`;
@@ -880,9 +880,31 @@ function renderKeys(keys) {
     .join("");
 }
 
-function buyCredits(keyName, btn) {
-  btnLoad(btn, "Redirecting\u2026");
+function buyCredits(keyName) {
+  const backdrop = document.getElementById("credits-backdrop");
+  backdrop._keyName = keyName;
+  document.getElementById("credits-key-name").textContent = keyName;
+  // default to first option
+  const radios = backdrop.querySelectorAll('input[name="credits-amount"]');
+  radios.forEach((r, i) => (r.checked = i === 0));
+  backdrop.classList.add("open");
+}
 
+function buyCreditsClose() {
+  document.getElementById("credits-backdrop").classList.remove("open");
+}
+
+function buyCreditsSubmit() {
+  const backdrop = document.getElementById("credits-backdrop");
+  const selected = backdrop.querySelector(
+    'input[name="credits-amount"]:checked',
+  );
+  if (!selected) {
+    toast("Please select an amount.", "warning");
+    return;
+  }
+
+  const keyName = backdrop._keyName;
   const params = new URLSearchParams(window.location.search);
   const activeAgent = agents.find((a) => a.UUID === activeUUID);
   const couponInput = document.getElementById("coupon-input");
@@ -891,6 +913,7 @@ function buyCredits(keyName, btn) {
   const fields = {
     product: "prod_Ufj2wCf4rhemT8",
     key: keyName || "",
+    value: selected.value,
     agent: activeUUID || "",
     period: "",
     location: activeAgent?.server || "",
@@ -908,11 +931,11 @@ function buyCredits(keyName, btn) {
   form.action = CREDITS_URL;
   form.target = "_self";
 
-  for (const [name, value] of Object.entries(fields)) {
+  for (const [name, val] of Object.entries(fields)) {
     const inp = document.createElement("input");
     inp.type = "hidden";
     inp.name = name;
-    inp.value = value;
+    inp.value = val;
     form.appendChild(inp);
   }
 
diff --git a/index.html b/index.html
index 2f300ea..ed0b2a9 100644
--- a/index.html
+++ b/index.html
@@ -875,6 +875,81 @@
         </div>
         <!-- /app-shell -->
 
+        <!-- ═══════════════════════════════════════════════════════════
+     BUY CREDITS MODAL
+════════════════════════════════════════════════════════════════ -->
+        <div id="credits-backdrop" class="modal-backdrop">
+            <div class="modal" style="max-width: 460px">
+                <div class="modal-header">
+                    <span class="modal-title">Buy Credits</span>
+                </div>
+                <div class="modal-body">
+                    <p class="credits-key-label">
+                        Credits will be assigned to key:
+                        <span id="credits-key-name"></span>
+                    </p>
+                    <div class="credits-options">
+                        <label class="credits-option">
+                            <input
+                                type="radio"
+                                name="credits-amount"
+                                value="5.50"
+                            />
+                            <span class="credits-option-label"
+                                >&euro;&thinsp;5.50</span
+                            >
+                        </label>
+                        <label class="credits-option">
+                            <input
+                                type="radio"
+                                name="credits-amount"
+                                value="11.00"
+                            />
+                            <span class="credits-option-label"
+                                >&euro;&thinsp;11.00</span
+                            >
+                        </label>
+                        <label class="credits-option">
+                            <input
+                                type="radio"
+                                name="credits-amount"
+                                value="22.00"
+                            />
+                            <span class="credits-option-label"
+                                >&euro;&thinsp;22.00</span
+                            >
+                        </label>
+                        <label class="credits-option">
+                            <input
+                                type="radio"
+                                name="credits-amount"
+                                value="55.00"
+                            />
+                            <span class="credits-option-label"
+                                >&euro;&thinsp;55.00</span
+                            >
+                        </label>
+                    </div>
+                    <p class="credits-fee-note">
+                        A 10% handling fee is added on top of the OpenRouter
+                        credits value.
+                    </p>
+                </div>
+                <div class="modal-footer">
+                    <button class="btn btn-ghost" onclick="buyCreditsClose()">
+                        Cancel
+                    </button>
+                    <button
+                        id="credits-buy-btn"
+                        class="btn btn-primary"
+                        onclick="buyCreditsSubmit()"
+                    >
+                        Buy Credits
+                    </button>
+                </div>
+            </div>
+        </div>
+
         <!-- ═══════════════════════════════════════════════════════════
      CONFIRM DIALOG
 ════════════════════════════════════════════════════════════════ -->
diff --git a/styles.css b/styles.css
index 685259c..1401b72 100644
--- a/styles.css
+++ b/styles.css
@@ -1438,6 +1438,71 @@ body::after {
     gap: 10px;
 }
 
+/* ─── Credits Modal ────────────────────────────────────────── */
+.credits-key-label {
+    font-size: 12px;
+    color: var(--text-muted);
+    margin: 0 0 14px;
+}
+
+.credits-key-label span {
+    color: var(--accent);
+    font-weight: 600;
+}
+
+.credits-options {
+    display: grid;
+    grid-template-columns: 1fr 1fr;
+    gap: 10px;
+    margin-bottom: 14px;
+}
+
+.credits-option {
+    display: flex;
+    align-items: center;
+    gap: 10px;
+    padding: 11px 14px;
+    background: var(--bg-inner);
+    border: 1px solid var(--border);
+    border-radius: var(--radius);
+    cursor: pointer;
+    transition:
+        border-color 0.15s,
+        background 0.15s;
+    user-select: none;
+}
+
+.credits-option:has(input:checked) {
+    border-color: var(--accent);
+    background: var(--accent-dim);
+}
+
+.credits-option input[type="radio"] {
+    accent-color: var(--accent);
+    width: 15px;
+    height: 15px;
+    flex-shrink: 0;
+    cursor: pointer;
+}
+
+.credits-option-label {
+    font-size: 15px;
+    font-weight: 600;
+    color: var(--text);
+    letter-spacing: 0.02em;
+}
+
+.credits-fee-note {
+    font-size: 12px;
+    color: var(--text-muted);
+    line-height: 1.55;
+    background: var(--bg-inner);
+    border: 1px solid var(--border);
+    border-radius: var(--radius);
+    padding: 10px 12px;
+    margin: 0;
+}
+
 /* ─── Utility ───────────────────────────────────────────────── */
 .text-muted {
     color: var(--text-muted);