diff --git a/cmd/testwrapper/testwrapper.go b/cmd/testwrapper/testwrapper.go
index 7cfb15a28..78c8b5ae9 100644
--- a/cmd/testwrapper/testwrapper.go
+++ b/cmd/testwrapper/testwrapper.go
@@ -38,12 +38,12 @@ const (
 )
 
 type testAttempt struct {
-	pkg           string // "tailscale.com/types/key"
-	testName      string // "TestFoo"
-	outcome       string // "pass", "fail", "skip"
+	pkg           string // "tailscale.com/types/key" `json:",inline"`
+	testName      string // "TestFoo" `json:",inline"`
+	outcome       string // "pass", "fail", "skip" `json:",omitempty"`
 	logs          bytes.Buffer
-	isMarkedFlaky bool   // set if the test is marked as flaky
-	issueURL      string // set if the test is marked as flaky
+	isMarkedFlaky bool   // set if the test is marked as flaky `json:",omitempty"`
+	issueURL      string // set if the test is marked as flaky `json:",omitempty"`
 
 	pkgFinished bool
 }
@@ -201,6 +201,12 @@ func main() {
 		return
 	}
 
+	f, err := os.Create("test_attempts.json")
+	if err != nil {
+		log.Printf("error creating test attempt json file: %v", err)
+	}
+	defer f.Close()
+
 	ctx := context.Background()
 	type nextRun struct {
 		tests   []*packageTests
@@ -320,6 +326,11 @@ func main() {
 				} else {
 					failed = true
 				}
+				testAttemptJson, _ := json.Marshal(tr)
+				_, err := f.Write(testAttemptJson)
+				if err != nil {
+					log.Printf("error appending to test attempt json file: %v", err)
+				}
 			}
 			if failed {
 				fmt.Println("\n\nNot retrying flaky tests because non-flaky tests failed.")