diff --git a/public/app.mjs b/public/app.mjs
index 4ee9202..08b8365 100644
--- a/public/app.mjs
+++ b/public/app.mjs
@@ -33,7 +33,9 @@ let all_bin_types = [];
 let bin_tab = 'bins'; // 'bins' | 'sources' | 'types'
 let bin_editor_instance = null;
 let bin_editor_bin_id = null;
+let bin_editor_get_fields = null;
 let bin_type_dialog_callback = null;
+let bin_content_dialog_callback = null;
 
 // ---------------------------------------------------------------------------
 // Data loading
@@ -159,6 +161,98 @@ function field_by_id(id) {
 	return all_fields.find(f => f.id === id);
 }
 
+// Attaches a reusable field editor UI to existing DOM elements.
+// Returns { get_fields() } — call get_fields() to collect trimmed non-empty values.
+function build_field_editor(rows_el, add_sel_el, new_btn_el, initial_fields) {
+	const active = new Map(Object.entries(initial_fields ?? {}));
+
+	function rebuild_rows() {
+		const sorted = [...active.entries()].sort(([a], [b]) =>
+			(field_by_id(a)?.name ?? a).localeCompare(field_by_id(b)?.name ?? b));
+		rows_el.replaceChildren(...sorted.map(([fid, val]) => {
+			const def = field_by_id(fid);
+			const row = document.createElement('div');
+			row.className = 'c-field-input-row';
+			const lbl = document.createElement('div');
+			lbl.className = 'c-field-input-label';
+			lbl.textContent = def ? def.name : fid;
+			if (def?.unit) {
+				const u = document.createElement('span');
+				u.className = 'c-field-unit-hint';
+				u.textContent = `[${def.unit}]`;
+				lbl.appendChild(u);
+			}
+			const inp = document.createElement('input');
+			inp.type = 'text';
+			inp.className = 'c-field-value';
+			inp.value = val;
+			inp.autocomplete = 'off';
+			inp.dataset.field_id = fid;
+			inp.addEventListener('input', e => active.set(fid, e.target.value));
+			const rm = document.createElement('button');
+			rm.type = 'button';
+			rm.className = 'btn-icon btn-danger';
+			rm.textContent = '✕';
+			rm.title = 'Remove field';
+			rm.addEventListener('click', () => { active.delete(fid); rebuild_rows(); rebuild_sel(); });
+			row.append(lbl, inp, rm);
+			return row;
+		}));
+	}
+
+	function rebuild_sel() {
+		const available = all_fields.filter(f => !active.has(f.id));
+		add_sel_el.replaceChildren(
+			Object.assign(document.createElement('option'), { value: '', textContent: '— add a field —' }),
+			...available.map(f => Object.assign(document.createElement('option'), {
+				value: f.id, textContent: f.name + (f.unit ? ` [${f.unit}]` : ''),
+			}))
+		);
+	}
+
+	rebuild_rows();
+	rebuild_sel();
+
+	const prev = add_sel_el._field_handler;
+	if (prev) add_sel_el.removeEventListener('change', prev);
+	add_sel_el._field_handler = (e) => {
+		const fid = e.target.value;
+		if (!fid) return;
+		active.set(fid, '');
+		rebuild_rows();
+		rebuild_sel();
+		rows_el.querySelector(`[data-field_id="${fid}"]`)?.focus();
+	};
+	add_sel_el.addEventListener('change', add_sel_el._field_handler);
+
+	if (new_btn_el) {
+		new_btn_el.onclick = () => {
+			const known = new Set(all_fields.map(f => f.id));
+			open_field_dialog(null);
+			document.getElementById('dialog-field').addEventListener('close', () => {
+				const nf = all_fields.find(f => !known.has(f.id));
+				rebuild_sel();
+				if (nf) {
+					active.set(nf.id, '');
+					rebuild_rows();
+					rebuild_sel();
+					rows_el.querySelector(`[data-field_id="${nf.id}"]`)?.focus();
+				}
+			}, { once: true });
+		};
+	}
+
+	return {
+		get_fields() {
+			const out = {};
+			for (const [fid, val] of active.entries()) {
+				if (val.trim()) out[fid] = val.trim();
+			}
+			return out;
+		},
+	};
+}
+
 function matches_search(component, query) {
 	if (!query) return true;
 	const words = query.toLowerCase().split(/\s+/).filter(Boolean);
@@ -2090,6 +2184,14 @@ function open_bin_type_dialog(bt = null) {
 	document.getElementById('bt-width').value = bt?.phys_w ?? '';
 	document.getElementById('bt-height').value = bt?.phys_h ?? '';
 	document.getElementById('bt-description').value = bt?.description ?? '';
+
+	const { get_fields } = build_field_editor(
+		document.getElementById('bt-field-rows'),
+		document.getElementById('bt-add-field-select'),
+		document.getElementById('bt-new-field'),
+		bt?.fields ?? {}
+	);
+
 	bin_type_dialog_callback = async () => {
 		const name = document.getElementById('bt-name').value.trim();
 		const phys_w = parseFloat(document.getElementById('bt-width').value);
@@ -2097,11 +2199,12 @@ function open_bin_type_dialog(bt = null) {
 		const description = document.getElementById('bt-description').value.trim();
 		if (!name) { alert('Name is required.'); return; }
 		if (!(phys_w > 0) || !(phys_h > 0)) { alert('Dimensions must be positive numbers.'); return; }
+		const fields = get_fields();
 		if (bt) {
-			const r = await api.update_bin_type(bt.id, { name, phys_w, phys_h, description });
+			const r = await api.update_bin_type(bt.id, { name, phys_w, phys_h, description, fields });
 			all_bin_types = all_bin_types.map(t => t.id === bt.id ? r.bin_type : t);
 		} else {
-			const r = await api.create_bin_type({ name, phys_w, phys_h, description });
+			const r = await api.create_bin_type({ name, phys_w, phys_h, description, fields });
 			all_bin_types = [...all_bin_types, r.bin_type].sort((a, b) => a.name.localeCompare(b.name));
 		}
 		render_bin_types_list();
@@ -2166,6 +2269,91 @@ function render_bin_source_list() {
 	}));
 }
 
+function render_bin_contents(bin_id, container_el) {
+	const bin = all_bins.find(b => b.id === bin_id);
+	const contents = bin?.contents ?? [];
+	if (contents.length === 0) {
+		const empty = clone('t-empty-block');
+		empty.textContent = 'No items yet.';
+		container_el.replaceChildren(empty);
+		return;
+	}
+	container_el.replaceChildren(...contents.map(item => {
+		const row = clone('t-bin-content-row');
+		let display_name = item.name ?? '';
+		if (item.type === 'component') {
+			const comp = all_components.find(c => c.id === item.component_id);
+			display_name = comp ? component_display_name(comp) : `[unknown component]`;
+		}
+		qs(row, '.bin-content-name').textContent = display_name;
+		qs(row, '.bin-content-qty').textContent = item.quantity ? `×${item.quantity}` : '';
+		qs(row, '.bin-content-notes').textContent = item.notes || '';
+		qs(row, '.btn-edit').addEventListener('click', () => open_bin_content_dialog(bin_id, item));
+		qs(row, '.btn-delete').addEventListener('click', async () => {
+			try {
+				await api.delete_bin_content(bin_id, item.id);
+				const cur = all_bins.find(b => b.id === bin_id);
+				const updated = { ...cur, contents: cur.contents.filter(c => c.id !== item.id) };
+				all_bins = all_bins.map(b => b.id === bin_id ? updated : b);
+				render_bin_contents(bin_id, container_el);
+			} catch (err) {
+				alert(err.message);
+			}
+		});
+		return row;
+	}));
+}
+
+function open_bin_content_dialog(bin_id, item = null) {
+	const dlg = document.getElementById('dialog-bin-content');
+	qs(dlg, '.dialog-title').textContent = item ? 'Edit item' : 'Add item';
+
+	const type_sel  = document.getElementById('bc-type');
+	const comp_row  = document.getElementById('bc-component-row');
+	const name_row  = document.getElementById('bc-name-row');
+	const comp_sel  = document.getElementById('bc-component');
+	const name_inp  = document.getElementById('bc-name');
+	const qty_inp   = document.getElementById('bc-quantity');
+	const notes_inp = document.getElementById('bc-notes');
+
+	comp_sel.replaceChildren(
+		new Option('— select —', ''),
+		...all_components.map(c => new Option(component_display_name(c), c.id))
+	);
+
+	type_sel.value   = item?.type ?? 'component';
+	comp_sel.value   = item?.component_id ?? '';
+	name_inp.value   = item?.name ?? '';
+	qty_inp.value    = item?.quantity ?? '';
+	notes_inp.value  = item?.notes ?? '';
+	type_sel.disabled = !!item;
+
+	function sync_type() {
+		const is_comp = type_sel.value === 'component';
+		comp_row.hidden = !is_comp;
+		name_row.hidden = is_comp;
+	}
+	type_sel.onchange = sync_type;
+	sync_type();
+
+	bin_content_dialog_callback = async () => {
+		const body = {
+			type:         type_sel.value,
+			component_id: type_sel.value === 'component' ? comp_sel.value : undefined,
+			name:         type_sel.value === 'item' ? name_inp.value.trim() : undefined,
+			quantity:     qty_inp.value.trim(),
+			notes:        notes_inp.value.trim(),
+		};
+		const result = item
+			? await api.update_bin_content(bin_id, item.id, body)
+			: await api.add_bin_content(bin_id, body);
+		all_bins = all_bins.map(b => b.id === bin_id ? result.bin : b);
+		render_bin_contents(bin_id, document.getElementById('bin-contents-list'));
+	};
+
+	dlg.showModal();
+}
+
 function open_bin_editor(bin) {
 	const dlg = document.getElementById('dialog-bin-editor');
 	if (!dlg) return;
@@ -2197,8 +2385,40 @@ function open_bin_editor(bin) {
 	type_sel.addEventListener('change', sync_dims_row);
 	sync_dims_row();
 
-	// Show dialog first so the canvas has correct layout dimensions before
-	// load_image reads parentElement.clientWidth to size itself.
+	// Tabs
+	let active_tab = 'corners';
+	const tab_panels = {
+		corners:  document.getElementById('bin-editor-tab-corners'),
+		fields:   document.getElementById('bin-editor-tab-fields'),
+		contents: document.getElementById('bin-editor-tab-contents'),
+	};
+	qs(dlg, '#bin-editor-tabs').onclick = (e) => {
+		const tab = e.target.dataset.tab;
+		if (!tab) return;
+		active_tab = tab;
+		qs(dlg, '#bin-editor-tabs').querySelectorAll('.tab-btn').forEach(btn => {
+			btn.classList.toggle('active', btn.dataset.tab === tab);
+		});
+		for (const [name, el] of Object.entries(tab_panels)) {
+			el.hidden = name !== tab;
+		}
+		const save_btn = document.getElementById('bin-editor-save');
+		save_btn.textContent = active_tab === 'corners' ? 'Save & process' : 'Save';
+	};
+
+	// Fields tab
+	bin_editor_get_fields = build_field_editor(
+		document.getElementById('bin-field-rows'),
+		document.getElementById('bin-add-field-select'),
+		document.getElementById('bin-new-field'),
+		bin.fields ?? {}
+	).get_fields;
+
+	// Contents tab
+	render_bin_contents(bin.id, document.getElementById('bin-contents-list'));
+	document.getElementById('bin-add-content').onclick = () => open_bin_content_dialog(bin.id);
+
+	// Show dialog first so the canvas has correct layout dimensions
 	dlg.showModal();
 
 	const canvas = document.getElementById('bin-editor-canvas');
@@ -2343,7 +2563,7 @@ async function init() {
 	const html = await fetch('/templates.html').then(r => r.text());
 	document.body.insertAdjacentHTML('beforeend', html);
 
-	for (const id of ['t-dialog-component', 't-dialog-inventory', 't-dialog-field', 't-dialog-confirm', 't-dialog-file-picker', 't-dialog-bin-editor', 't-dialog-bin-type']) {
+	for (const id of ['t-dialog-component', 't-dialog-inventory', 't-dialog-field', 't-dialog-confirm', 't-dialog-file-picker', 't-dialog-bin-editor', 't-dialog-bin-type', 't-dialog-bin-content']) {
 		document.body.appendChild(document.getElementById(id).content.cloneNode(true));
 	}
 
@@ -2453,26 +2673,46 @@ async function init() {
 	});
 
 	document.getElementById('bin-editor-save').addEventListener('click', async () => {
-		const corners = bin_editor_instance?.get_corners();
+		const id = bin_editor_bin_id;
 		const name = document.getElementById('bin-editor-name').value.trim() || 'Bin';
 		const type_id = document.getElementById('bin-editor-type').value || null;
-		const phys_w = parseFloat(document.getElementById('bin-editor-width').value) || null;
-		const phys_h = parseFloat(document.getElementById('bin-editor-height').value) || null;
-		if (!corners) { alert('Load an image first.'); return; }
-		const id = bin_editor_bin_id;
+		const fields = bin_editor_get_fields?.() ?? {};
 		try {
-			await api.update_bin(id, { name, type_id });
-			const r = await api.update_bin_corners(id, corners, phys_w, phys_h);
-			all_bins = all_bins.map(b => b.id === id ? r.bin : b);
+			// Always save name, type, and fields
+			const corners = bin_editor_instance?.get_corners();
+			if (corners) {
+				// Corners tab active (or image loaded) — also re-process
+				const phys_w = parseFloat(document.getElementById('bin-editor-width').value) || null;
+				const phys_h = parseFloat(document.getElementById('bin-editor-height').value) || null;
+				await api.update_bin(id, { name, type_id, fields });
+				const r = await api.update_bin_corners(id, corners, phys_w, phys_h);
+				all_bins = all_bins.map(b => b.id === id ? r.bin : b);
+			} else {
+				const r = await api.update_bin(id, { name, type_id, fields });
+				all_bins = all_bins.map(b => b.id === id ? r.bin : b);
+			}
 			document.getElementById('dialog-bin-editor').close();
 			bin_editor_instance = null;
 			bin_editor_bin_id = null;
+			bin_editor_get_fields = null;
 			render_bins();
 		} catch (err) {
 			alert(err.message);
 		}
 	});
 
+	document.getElementById('bc-cancel').addEventListener('click', () => {
+		document.getElementById('dialog-bin-content').close();
+	});
+	document.getElementById('bc-save').addEventListener('click', async () => {
+		try {
+			await bin_content_dialog_callback?.();
+			document.getElementById('dialog-bin-content').close();
+		} catch (err) {
+			alert(err.message);
+		}
+	});
+
 	document.querySelectorAll('.nav-btn').forEach(btn => {
 		btn.addEventListener('click', () => navigate('/' + btn.dataset.section));
 	});
diff --git a/public/style.css b/public/style.css
index 14d0d49..1c1e279 100644
--- a/public/style.css
+++ b/public/style.css
@@ -2033,3 +2033,36 @@ nav {
 	text-overflow: ellipsis;
 	white-space: nowrap;
 }
+
+.bin-content-row {
+	display: flex;
+	align-items: center;
+	gap: 0.75rem;
+	padding: 0.4rem 0;
+	border-bottom: 1px solid var(--border);
+}
+
+.bin-content-name {
+	flex: 1;
+	font-weight: 500;
+	min-width: 0;
+	overflow: hidden;
+	text-overflow: ellipsis;
+	white-space: nowrap;
+}
+
+.bin-content-qty {
+	font-size: 0.85rem;
+	color: var(--text-muted);
+	flex-shrink: 0;
+}
+
+.bin-content-notes {
+	font-size: 0.8rem;
+	color: var(--text-faint);
+	flex: 1;
+	min-width: 0;
+	overflow: hidden;
+	text-overflow: ellipsis;
+	white-space: nowrap;
+}