diff --git a/index.js b/index.js
index d4c1253d..79bfce1b 100644
--- a/index.js
+++ b/index.js
@@ -93,10 +93,10 @@ const createMeasurement = async (req, res, client, getCurrentRound) => {
     measurement.protocol,
     measurement.participantAddress,
     measurement.timeout || false,
-    new Date(measurement.startAt),
+    parseOptionalDate(measurement.startAt),
     measurement.statusCode,
-    new Date(measurement.firstByteAt),
-    new Date(measurement.endAt),
+    parseOptionalDate(measurement.firstByteAt),
+    parseOptionalDate(measurement.endAt),
     measurement.byteLength,
     measurement.attestation,
     inetGroup,
@@ -285,3 +285,18 @@ export const createHandler = async ({
       })
   }
 }
+
+/**
+ * Parse a date string field that may be `undefined` or `null`.
+ *
+ * - undefined -> undefined
+ * - null -> undefined
+ * - "iso-date-string" -> new Date("iso-date-string")
+ *
+ * @param {string | null | undefined} str
+ * @returns {Date | undefined}
+ */
+const parseOptionalDate = (str) => {
+  if (str === undefined || str === null) return undefined
+  return new Date(str)
+}
diff --git a/spark-publish/test/test.js b/spark-publish/test/test.js
index 8fe35cff..78c5e7bc 100644
--- a/spark-publish/test/test.js
+++ b/spark-publish/test/test.js
@@ -98,7 +98,7 @@ describe('integration', () => {
       startAt: new Date('2023-09-18T13:33:51.239Z'),
       statusCode: 200,
       firstByteAt: new Date('2023-09-18T13:33:51.239Z'),
-      endAt: new Date('2023-09-18T13:33:51.239Z'),
+      endAt: null,
       byteLength: 100,
       attestation: 'json.sig',
       inetGroup: 'MTIzNDU2Nzg',
@@ -208,6 +208,7 @@ describe('integration', () => {
     assert.strictEqual(published.cid, measurementRecorded.cid)
     assert.strictEqual(published.inet_group, measurementRecorded.inetGroup)
     assert.strictEqual(published.car_too_large, measurementRecorded.carTooLarge)
+    assert.strictEqual(published.end_at, null)
     // TODO: test other fields
 
     // We are publishing records with invalid wallet addresses too
diff --git a/test/test.js b/test/test.js
index 08020ee3..9377d4dd 100644
--- a/test/test.js
+++ b/test/test.js
@@ -213,6 +213,43 @@ describe('Routes', () => {
       ])
       assert.strictEqual(measurementRow.participant_address, participantAddress)
     })
+
+    it('handles date fields set to null', async () => {
+      await client.query('DELETE FROM measurements')
+
+      const measurement = {
+        cid: 'bafytest',
+        providerAddress: '/dns4/localhost/tcp/8080',
+        protocol: 'graphsync',
+        sparkVersion: '1.2.3',
+        zinniaVersion: '2.3.4',
+        participantAddress,
+        startAt: new Date(),
+        statusCode: undefined,
+        firstByteAt: null,
+        endAt: null
+      }
+
+      const createRequest = await fetch(`${spark}/measurements`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify(measurement)
+      })
+      await assertResponseStatus(createRequest, 200)
+      const { id } = await createRequest.json()
+
+      const { rows: [measurementRow] } = await client.query(`
+          SELECT *
+          FROM measurements
+          WHERE id = $1
+        `, [
+        id
+      ])
+
+      assert.strictEqual(measurementRow.status_code, null)
+      assert.strictEqual(measurementRow.first_byte_at, null)
+      assert.strictEqual(measurementRow.end_at, null)
+    })
   })
 
   describe('GET /measurements/:id', () => {