diff --git a/assets/i18n/en/main.ftl b/assets/i18n/en/main.ftl
index e042d65..f3c90b6 100644
--- a/assets/i18n/en/main.ftl
+++ b/assets/i18n/en/main.ftl
@@ -213,6 +213,8 @@ variants-options = Variants / options
 add-option = Add option
 option-label = Option label
 optional = optional
+stock-untracked-hint = Leave blank = available without stock tracking
+available = Available
 choose-option = Choose an option
 from-price = from { $price }
 admin-discounts = Discounts
diff --git a/assets/i18n/sk/main.ftl b/assets/i18n/sk/main.ftl
index b107e58..57ac596 100644
--- a/assets/i18n/sk/main.ftl
+++ b/assets/i18n/sk/main.ftl
@@ -213,6 +213,8 @@ variants-options = Varianty / možnosti
 add-option = Pridať možnosť
 option-label = Označenie možnosti
 optional = voliteľné
+stock-untracked-hint = Nechajte prázdne = dostupné bez sledovania zásob
+available = Dostupné
 choose-option = Vyberte možnosť
 from-price = od { $price }
 admin-discounts = Zľavy
diff --git a/assets/views/admin/catalog/product_form.html b/assets/views/admin/catalog/product_form.html
index b72e162..5130279 100644
--- a/assets/views/admin/catalog/product_form.html
+++ b/assets/views/admin/catalog/product_form.html
@@ -37,10 +37,11 @@
 
   {# --- Variants / options editor ------------------------------------------- #}
   {# Each product is sold as one or more variants (a free-text label such as     #}
-  {# "10cm x 13cm" or "5ml" plus its own price/stock, optional sku & business    #}
-  {# price). Price and stock are required; the browser blocks save if a row is    #}
-  {# incomplete. Rows are managed client-side; names are indexed (variants[i][…]) #}
-  {# and read back by the controller.                                             #}
+  {# "10cm x 13cm" or "5ml" plus its own price). Price is required. Stock is      #}
+  {# optional — leave it blank ("∞") to mark the option simply available (not     #}
+  {# inventory-tracked). SKU and business price are optional too. Rows are        #}
+  {# managed client-side; names are indexed (variants[i][…]) and read back by     #}
+  {# the controller.                                                              #}
   {% set opt = " (" ~ t(key="optional", lang=lang | default(value='sk')) ~ ")" %}
   <script id="variants-data" type="application/json">{{ variants | json_encode() | safe }}</script>
   <div class="space-y-3" x-data="variantEditor(JSON.parse(document.getElementById('variants-data').textContent))">
@@ -68,8 +69,8 @@
             <input :name="`variants[${i}][sku]`" x-model="row.sku" class="{{ inp }}">
           </div>
           <div class="space-y-1 sm:col-span-2">
-            <label class="{{ sublabel }} block truncate">{{ t(key="stock", lang=lang | default(value='sk')) }}</label>
-            <input type="number" min="0" required :name="`variants[${i}][stock]`" x-model="row.stock" class="{{ inp }}">
+            <label class="{{ sublabel }} block truncate">{{ t(key="stock", lang=lang | default(value='sk')) }}{{ opt }}</label>
+            <input type="number" min="0" :name="`variants[${i}][stock]`" x-model="row.stock" class="{{ inp }}" placeholder="∞" title="{{ t(key='stock-untracked-hint', lang=lang | default(value='sk')) }}">
           </div>
           <div class="space-y-1 sm:col-span-2">
             <label class="{{ sublabel }} block truncate">{{ t(key="price", lang=lang | default(value='sk')) }}</label>
diff --git a/assets/views/shop/_card.html b/assets/views/shop/_card.html
index e7b81d4..6decfc9 100644
--- a/assets/views/shop/_card.html
+++ b/assets/views/shop/_card.html
@@ -32,8 +32,8 @@
     {% if product.has_options %}
     {# Multiple variants: customer must pick on the product page. #}
     {{ ui::button(label=t(key="choose-option", lang=lang | default(value='sk')), href="/shop/" ~ product.slug, extra="w-full") }}
-    {% elif product.stock > 0 %}
-    <p class="text-xs text-on-surface/60 dark:text-on-surface-dark/60">{{ t(key="in-stock", lang=lang | default(value='sk')) }}: {{ product.stock }}</p>
+    {% elif product.in_stock %}
+    <p class="text-xs text-on-surface/60 dark:text-on-surface-dark/60">{% if product.tracked %}{{ t(key="in-stock", lang=lang | default(value='sk')) }}: {{ product.stock }}{% else %}{{ t(key="available", lang=lang | default(value='sk')) }}{% endif %}</p>
     <form method="post" action="/cart/add" hx-post="/cart/add" hx-swap="none"
       hx-on::after-request="if (event.detail.successful) toast('{{ t(key='cart-added', lang=lang | default(value='sk')) }}')">
   <input type="hidden" name="_csrf" value="{{ csrf_token() }}">
diff --git a/assets/views/shop/_cart_body.html b/assets/views/shop/_cart_body.html
index 448e642..cfe0a94 100644
--- a/assets/views/shop/_cart_body.html
+++ b/assets/views/shop/_cart_body.html
@@ -37,7 +37,7 @@
             hx-post="/cart/update" hx-trigger="cartchange" hx-target="#cart-body" hx-swap="innerHTML">
   {{ ui::csrf_field() }}
             <input type="hidden" name="variant_id" value="{{ item.id }}">
-            <input type="number" name="quantity" min="0" max="{{ item.stock }}" value="{{ item.quantity }}"
+            <input type="number" name="quantity" min="0" {% if item.stock %}max="{{ item.stock }}"{% endif %} value="{{ item.quantity }}"
               @change="
                 if (parseInt($el.value || '0') <= 0 && !window.confirm('{{ t(key='cart-remove-confirm', lang=lang | default(value='sk')) }}')) {
                   $el.value = '{{ item.quantity }}';
diff --git a/assets/views/shop/show.html b/assets/views/shop/show.html
index 3fce2bd..a9162e6 100644
--- a/assets/views/shop/show.html
+++ b/assets/views/shop/show.html
@@ -98,7 +98,14 @@
               </div>
               <button type="submit" class="{{ btn }}">{{ t(key="add-to-cart", lang=lang | default(value='sk')) }}</button>
             </form>
-            <p class="text-sm text-on-surface/60 dark:text-on-surface-dark/60">{{ t(key="in-stock", lang=lang | default(value='sk')) }}: <span x-text="current.stock"></span></p>
+            <p class="text-sm text-on-surface/60 dark:text-on-surface-dark/60">
+              <template x-if="current.tracked">
+                <span>{{ t(key="in-stock", lang=lang | default(value='sk')) }}: <span x-text="current.stock"></span></span>
+              </template>
+              <template x-if="!current.tracked">
+                <span>{{ t(key="available", lang=lang | default(value='sk')) }}</span>
+              </template>
+            </p>
           </div>
         </template>
         <template x-if="!current.in_stock">
diff --git a/migration/src/lib.rs b/migration/src/lib.rs
index 276f8a4..67e00f4 100644
--- a/migration/src/lib.rs
+++ b/migration/src/lib.rs
@@ -41,6 +41,7 @@ mod m20260621_000003_discount_profiles;
 mod m20260621_000004_add_business_sale_price_to_products;
 mod m20260622_000001_audience_discount_profiles;
 mod m20260622_000002_product_variants;
+mod m20260622_000003_variant_stock_nullable;
 pub struct Migrator;
 
 #[async_trait::async_trait]
@@ -86,6 +87,7 @@ impl MigratorTrait for Migrator {
             Box::new(m20260621_000004_add_business_sale_price_to_products::Migration),
             Box::new(m20260622_000001_audience_discount_profiles::Migration),
             Box::new(m20260622_000002_product_variants::Migration),
+            Box::new(m20260622_000003_variant_stock_nullable::Migration),
             // inject-above (do not remove this comment)
         ]
     }
diff --git a/migration/src/m20260622_000003_variant_stock_nullable.rs b/migration/src/m20260622_000003_variant_stock_nullable.rs
new file mode 100644
index 0000000..829ba9c
--- /dev/null
+++ b/migration/src/m20260622_000003_variant_stock_nullable.rs
@@ -0,0 +1,36 @@
+//! Make `product_variants.stock` nullable: a NULL stock means the variant is
+//! "available" but not inventory-tracked — always purchasable, no quantity cap,
+//! and never decremented on order. A numeric stock is tracked/capped as before.
+
+use sea_orm_migration::prelude::*;
+
+#[derive(DeriveMigrationName)]
+pub struct Migration;
+
+#[async_trait::async_trait]
+impl MigrationTrait for Migration {
+    async fn up(&self, m: &SchemaManager) -> Result<(), DbErr> {
+        m.get_connection()
+            .execute_unprepared(
+                r#"
+                ALTER TABLE product_variants ALTER COLUMN stock DROP DEFAULT;
+                ALTER TABLE product_variants ALTER COLUMN stock DROP NOT NULL;
+                "#,
+            )
+            .await?;
+        Ok(())
+    }
+
+    async fn down(&self, m: &SchemaManager) -> Result<(), DbErr> {
+        m.get_connection()
+            .execute_unprepared(
+                r#"
+                UPDATE product_variants SET stock = 0 WHERE stock IS NULL;
+                ALTER TABLE product_variants ALTER COLUMN stock SET DEFAULT 0;
+                ALTER TABLE product_variants ALTER COLUMN stock SET NOT NULL;
+                "#,
+            )
+            .await?;
+        Ok(())
+    }
+}
diff --git a/src/controllers/admin_products.rs b/src/controllers/admin_products.rs
index 9022e54..3ff0ee7 100644
--- a/src/controllers/admin_products.rs
+++ b/src/controllers/admin_products.rs
@@ -102,7 +102,8 @@ struct VariantInput {
     id: Option<i32>,
     label: String,
     sku: Option<String>,
-    stock: i32,
+    /// `None` = available but not inventory-tracked.
+    stock: Option<i32>,
     price_cents: i64,
     business_sale_cents: Option<i64>,
     position: i32,
@@ -156,11 +157,17 @@ fn parse_variants(form: &MultipartForm) -> Result<Vec<VariantInput>> {
         }
 
         let sku = form.text(&format!("variants[{i}][sku]"));
-        let stock = form
-            .text(&format!("variants[{i}][stock]"))
-            .and_then(|s| s.parse::<i32>().ok())
-            .filter(|n| *n >= 0)
-            .ok_or_else(|| Error::BadRequest("each option needs a stock quantity".to_string()))?;
+        // Stock is optional: blank means "available, not tracked". A value must
+        // be a non-negative integer.
+        let stock = match form.text(&format!("variants[{i}][stock]")) {
+            None => None,
+            Some(raw) => Some(
+                raw.parse::<i32>()
+                    .ok()
+                    .filter(|n| *n >= 0)
+                    .ok_or_else(|| Error::BadRequest("stock must be 0 or more".to_string()))?,
+            ),
+        };
         let business_sale_cents = parse_optional_sale(form, i, "business_sale", price_cents)?;
         let id = form
             .text(&format!("variants[{i}][id]"))
@@ -315,12 +322,22 @@ async fn index(
         let category_name = product
             .category_id
             .and_then(|id| category_name.get(&id).cloned());
-        let total_stock: i32 = variants.iter().map(|v| v.stock).sum();
+        // Stock column: total across tracked variants, or "∞" when any option is
+        // untracked (always available).
+        let stock_display = if variants.iter().any(|v| !v.tracked()) {
+            "∞".to_string()
+        } else {
+            variants
+                .iter()
+                .filter_map(|v| v.stock)
+                .sum::<i32>()
+                .to_string()
+        };
         rows.push(product_row(
             product,
             priced,
             variants.len(),
-            total_stock,
+            stock_display,
             image,
             category_name,
         ));
@@ -349,7 +366,7 @@ fn product_row(
     product: &products::Model,
     effective: &pricing::PricedProduct,
     variant_count: usize,
-    total_stock: i32,
+    stock_display: String,
     image: Option<String>,
     category_name: Option<String>,
 ) -> serde_json::Value {
@@ -358,7 +375,7 @@ fn product_row(
         "name": product.name,
         "slug": product.slug,
         "currency": product.currency,
-        "stock": total_stock,
+        "stock": stock_display,
         "variant_count": variant_count,
         "has_options": variant_count > 1,
         "published": product.published,
diff --git a/src/controllers/cart.rs b/src/controllers/cart.rs
index a693b98..44a215a 100644
--- a/src/controllers/cart.rs
+++ b/src/controllers/cart.rs
@@ -97,9 +97,9 @@ async fn add(
     let mut items = parse_cart(&jar);
     let add_qty = form.quantity.unwrap_or(1).max(1);
     if let Some(entry) = items.iter_mut().find(|(id, _)| *id == variant.id) {
-        entry.1 = (entry.1 + add_qty).min(variant.stock);
+        entry.1 = variant.cap(entry.1 + add_qty);
     } else {
-        items.push((variant.id, add_qty.min(variant.stock)));
+        items.push((variant.id, variant.cap(add_qty)));
     }
     items.retain(|(_, qty)| *qty > 0);
 
@@ -128,13 +128,14 @@ async fn update(
     headers: HeaderMap,
     Form(form): Form<UpdateForm>,
 ) -> Result<Response> {
-    let stock = published_variant(&ctx, form.variant_id)
-        .await?
-        .map(|(v, _)| v.stock)
-        .unwrap_or(0);
+    // Clamp the requested quantity to what's available (no cap for untracked
+    // variants); a removed variant clamps to 0 and drops out below.
+    let clamped = match published_variant(&ctx, form.variant_id).await? {
+        Some((variant, _)) => variant.cap(form.quantity),
+        None => 0,
+    };
 
     let mut items = parse_cart(&jar);
-    let clamped = form.quantity.clamp(0, stock);
     if let Some(entry) = items.iter_mut().find(|(id, _)| *id == form.variant_id) {
         entry.1 = clamped;
     }
@@ -208,7 +209,7 @@ pub(crate) async fn resolve_cart(
         let Some((variant, product)) = published_variant(ctx, id).await? else {
             continue;
         };
-        let qty = qty.clamp(0, variant.stock);
+        let qty = variant.cap(qty);
         if qty == 0 {
             continue;
         }
diff --git a/src/models/_entities/product_variants.rs b/src/models/_entities/product_variants.rs
index 1596b92..1f87e1d 100644
--- a/src/models/_entities/product_variants.rs
+++ b/src/models/_entities/product_variants.rs
@@ -14,7 +14,7 @@ pub struct Model {
     pub label: String,
     pub position: i32,
     pub sku: Option<String>,
-    pub stock: i32,
+    pub stock: Option<i32>,
     pub price_cents: i64,
     pub sale_price_cents: Option<i64>,
     pub business_sale_price_cents: Option<i64>,
diff --git a/src/models/orders.rs b/src/models/orders.rs
index 875b33b..044b4c1 100644
--- a/src/models/orders.rs
+++ b/src/models/orders.rs
@@ -65,11 +65,15 @@ pub async fn place(
             .one(&txn)
             .await?
             .ok_or_else(|| Error::BadRequest("a product is no longer available".to_string()))?;
-        if variant.stock < *qty {
-            return Err(Error::BadRequest(format!(
-                "not enough stock for {}",
-                product.name
-            )));
+        // Tracked variants can't oversell; untracked ones (stock = None) are
+        // always available and never decremented.
+        if let Some(on_hand) = variant.stock {
+            if on_hand < *qty {
+                return Err(Error::BadRequest(format!(
+                    "not enough stock for {}",
+                    product.name
+                )));
+            }
         }
         currency = product.currency.clone();
         // Snapshot the price the buyer actually pays — public sale or, for a
@@ -78,9 +82,11 @@ pub async fn place(
         let unit_price_cents = pricing::price_variant(ctx, &variant, user).await?.price_cents;
         subtotal += unit_price_cents * i64::from(*qty);
 
-        let mut active = variant.clone().into_active_model();
-        active.stock = Set(variant.stock - *qty);
-        active.update(&txn).await?;
+        if let Some(on_hand) = variant.stock {
+            let mut active = variant.clone().into_active_model();
+            active.stock = Set(Some(on_hand - *qty));
+            active.update(&txn).await?;
+        }
 
         snapshots.push((product.id, variant.id, product.name, variant.label, unit_price_cents, *qty));
     }
diff --git a/src/models/product_variants.rs b/src/models/product_variants.rs
index 22c8001..9710ad6 100644
--- a/src/models/product_variants.rs
+++ b/src/models/product_variants.rs
@@ -45,6 +45,30 @@ impl Model {
     pub fn business_on_sale(&self) -> bool {
         matches!(self.business_sale_price_cents, Some(sale) if sale < self.price_cents)
     }
+
+    /// Whether the variant's inventory is tracked. A `None` stock means
+    /// "available, not tracked" (always purchasable, unlimited).
+    #[must_use]
+    pub fn tracked(&self) -> bool {
+        self.stock.is_some()
+    }
+
+    /// Whether the variant can currently be bought: untracked variants are always
+    /// available; tracked ones need a positive quantity on hand.
+    #[must_use]
+    pub fn in_stock(&self) -> bool {
+        self.stock.map_or(true, |s| s > 0)
+    }
+
+    /// Clamp a desired quantity to what's available: capped at the tracked stock,
+    /// or left as-is (only floored at 0) when untracked.
+    #[must_use]
+    pub fn cap(&self, qty: i32) -> i32 {
+        match self.stock {
+            Some(s) => qty.clamp(0, s),
+            None => qty.max(0),
+        }
+    }
 }
 
 // implement your write-oriented logic here
diff --git a/src/seed.rs b/src/seed.rs
index f622871..0c5f2ed 100644
--- a/src/seed.rs
+++ b/src/seed.rs
@@ -177,7 +177,7 @@ pub async fn seed_catalog(ctx: &AppContext) -> Result<()> {
             label: Set(String::new()),
             position: Set(0),
             sku: Set(item.sku.map(|s| s.to_string())),
-            stock: Set(item.stock),
+            stock: Set(Some(item.stock)),
             price_cents: Set(item.price_cents),
             ..Default::default()
         }
diff --git a/src/views/shop.rs b/src/views/shop.rs
index bbf09d9..a946ac0 100644
--- a/src/views/shop.rs
+++ b/src/views/shop.rs
@@ -34,6 +34,8 @@ pub fn product_card(
         "currency": product.currency,
         "sku": representative.sku,
         "stock": representative.stock,
+        "tracked": representative.tracked(),
+        "in_stock": representative.in_stock(),
         "variant_count": variant_count,
         "has_options": variant_count > 1,
         "published": product.published,
@@ -49,7 +51,8 @@ pub fn variant_option(variant: &product_variants::Model, priced: &PricedProduct)
         "label": variant.label,
         "sku": variant.sku,
         "stock": variant.stock,
-        "in_stock": variant.stock > 0,
+        "tracked": variant.tracked(),
+        "in_stock": variant.in_stock(),
         "price": format_price(priced.price_cents),
         "on_sale": priced.is_reduced(),
         "regular_price": format_price(priced.regular_cents),