diff --git a/src/fn/solderjumper.ts b/src/fn/solderjumper.ts
index af1b7d20..0123e0eb 100644
--- a/src/fn/solderjumper.ts
+++ b/src/fn/solderjumper.ts
@@ -20,13 +20,13 @@ import { length } from "circuit-json"
  *   solderjumper({ num_pins: 3, pw: 2.0, ph: 1.0 }) // custom pad size
  */
 export const solderjumper = (params: {
-  num_pins: 2 | 3
+  num_pins?: 2 | 3
   bridged?: string
   p?: number
   pw?: number
   ph?: number
 }) => {
-  const { num_pins, bridged, p = 2.54, pw = 1.5, ph = 1.5 } = params
+  const { num_pins = 2, bridged, p = 2.54, pw = 1.5, ph = 1.5 } = params
   const padSpacing = length.parse(p)
   const padWidth = length.parse(pw)
   const padHeight = length.parse(ph)
diff --git a/tests/solderjumper-bare-string.test.ts b/tests/solderjumper-bare-string.test.ts
new file mode 100644
index 00000000..591a2e30
--- /dev/null
+++ b/tests/solderjumper-bare-string.test.ts
@@ -0,0 +1,22 @@
+import { test, expect } from "bun:test"
+import { fp } from "../src"
+
+test("solderjumper bare string defaults to 2 pins and emits finite geometry (#784)", () => {
+  const circuitJson = fp.string("solderjumper").circuitJson()
+
+  const smtpads = circuitJson.filter((e) => e.type === "pcb_smtpad")
+  expect(smtpads.length).toBe(2)
+
+  const courtyard = circuitJson.find((e) => e.type === "pcb_courtyard_rect") as any
+  expect(courtyard).toBeDefined()
+  expect(Number.isFinite(courtyard.width)).toBe(true)
+  expect(Number.isFinite(courtyard.height)).toBe(true)
+  expect(Number.isFinite(courtyard.center.x)).toBe(true)
+  expect(Number.isFinite(courtyard.center.y)).toBe(true)
+
+  const text = circuitJson.find((e) => e.type === "pcb_silkscreen_text") as any
+  if (text) {
+    expect(Number.isFinite(text.anchor_position.x)).toBe(true)
+    expect(Number.isFinite(text.anchor_position.y)).toBe(true)
+  }
+})