diff --git a/frontend/tests/admin.spec.ts b/frontend/tests/admin.spec.ts
index 490810e..192841e 100644
--- a/frontend/tests/admin.spec.ts
+++ b/frontend/tests/admin.spec.ts
@@ -1,9 +1,24 @@
 import { expect, test } from "@playwright/test"
 import { firstSuperuser, firstSuperuserPassword } from "./config.ts"
+import { api, apiPage } from "./utils/api"
 import { createUser } from "./utils/privateApi"
 import { randomEmail, randomPassword } from "./utils/random"
 import { logInUser } from "./utils/user"
 
+test.afterAll(async ({ browser }) => {
+  // Every user below is created under a randomEmail(), so the superuser can
+  // sweep them all up by that shape — including what a run that failed halfway
+  // left in the shared development database.
+  const page = await apiPage(browser)
+  const { data } = await (await api(page, "/users/?limit=1000")).json()
+  for (const user of data as { id: string; email: string }[]) {
+    if (/^test_.*@example\.com$/.test(user.email)) {
+      await api(page, `/users/${user.id}`, { method: "DELETE" })
+    }
+  }
+  await page.close()
+})
+
 test("Admin page is accessible and shows correct title", async ({ page }) => {
   await page.goto("/admin")
   await expect(page.getByRole("heading", { name: "Users" })).toBeVisible()
diff --git a/frontend/tests/drafts.spec.ts b/frontend/tests/drafts.spec.ts
index 8c64565..a9e7bea 100644
--- a/frontend/tests/drafts.spec.ts
+++ b/frontend/tests/drafts.spec.ts
@@ -1,4 +1,5 @@
-import { expect, type Page, test } from "@playwright/test"
+import { expect, test } from "@playwright/test"
+import { api, deleteAll } from "./utils/api"
 
 /**
  * Editing writes a draft; only publishing hands it to the engine. The two
@@ -12,19 +13,9 @@ test.use({ storageState: "playwright/.auth/user.json" })
 
 test.describe.configure({ mode: "serial" })
 
-const apiUrl = process.env.VITE_API_URL || "http://api.localhost"
-
-async function api(
-  page: Page,
-  path: string,
-  init: Record<string, unknown> = {},
-) {
-  const token = await page.evaluate(() => localStorage.getItem("access_token"))
-  return page.request.fetch(`${apiUrl}/api/v1${path}`, {
-    ...init,
-    headers: { Authorization: `Bearer ${token}` },
-  })
-}
+test.afterAll(async ({ browser }) => {
+  await deleteAll(browser, [`/flows/${flowName}`])
+})
 
 test("a draft stays off the engine until it is published", async ({ page }) => {
   await page.goto("/flows")
@@ -93,6 +84,4 @@ test("discarding a draft goes back to the published flow", async ({ page }) => {
   const detail = await (await api(page, `/flows/${flowName}`)).json()
   expect(detail.has_draft).toBe(false)
   expect(detail.definition.title).not.toBe("Theirs")
-
-  await api(page, `/flows/${flowName}`, { method: "DELETE" })
 })
diff --git a/frontend/tests/endpoints.spec.ts b/frontend/tests/endpoints.spec.ts
index db7250d..32b2de8 100644
--- a/frontend/tests/endpoints.spec.ts
+++ b/frontend/tests/endpoints.spec.ts
@@ -1,4 +1,5 @@
-import { expect, type Page, test } from "@playwright/test"
+import { expect, test } from "@playwright/test"
+import { api, apiPage, deleteAll } from "./utils/api"
 
 /**
  * Dashboards and other flows appear on the canvas but are not part of the flow.
@@ -16,25 +17,8 @@ test.use({ storageState: "playwright/.auth/user.json" })
 
 test.describe.configure({ mode: "serial" })
 
-const apiUrl = process.env.VITE_API_URL || "http://api.localhost"
-
-async function api(
-  page: Page,
-  path: string,
-  init: Record<string, unknown> = {},
-) {
-  const token = await page.evaluate(() => localStorage.getItem("access_token"))
-  return page.request.fetch(`${apiUrl}/api/v1${path}`, {
-    ...init,
-    headers: { Authorization: `Bearer ${token}` },
-  })
-}
-
 test.beforeAll(async ({ browser }) => {
-  const page = await browser.newPage({
-    storageState: "playwright/.auth/user.json",
-  })
-  await page.goto("/")
+  const page = await apiPage(browser)
 
   // A flow reading a message, and a dashboard control that sets it.
   await api(page, `/flows/${flowName}`, {
@@ -82,13 +66,10 @@ test.beforeAll(async ({ browser }) => {
 })
 
 test.afterAll(async ({ browser }) => {
-  const page = await browser.newPage({
-    storageState: "playwright/.auth/user.json",
-  })
-  await page.goto("/")
-  await api(page, `/dashboards/${dashboardName}`, { method: "DELETE" })
-  await api(page, `/flows/${flowName}`, { method: "DELETE" })
-  await page.close()
+  await deleteAll(browser, [
+    `/dashboards/${dashboardName}`,
+    `/flows/${flowName}`,
+  ])
 })
 
 test("a dashboard control is drawn on the flow it feeds", async ({ page }) => {
diff --git a/frontend/tests/flows.spec.ts b/frontend/tests/flows.spec.ts
index 333e080..e6a5a68 100644
--- a/frontend/tests/flows.spec.ts
+++ b/frontend/tests/flows.spec.ts
@@ -1,4 +1,5 @@
 import { expect, type Page, test } from "@playwright/test"
+import { deleteAll } from "./utils/api"
 
 /**
  * The flow editor's load-bearing behaviour: nodes are placed, connections come
@@ -12,6 +13,10 @@ test.use({ storageState: "playwright/.auth/user.json" })
 
 test.describe.configure({ mode: "serial" })
 
+test.afterAll(async ({ browser }) => {
+  await deleteAll(browser, [`/flows/${flowName}`])
+})
+
 const apiUrl = process.env.VITE_API_URL || "http://api.localhost"
 
 /** Write a node's source through the API; typing code is not what we test. */
diff --git a/frontend/tests/runtime.spec.ts b/frontend/tests/runtime.spec.ts
index ae12b5c..25b5006 100644
--- a/frontend/tests/runtime.spec.ts
+++ b/frontend/tests/runtime.spec.ts
@@ -1,4 +1,5 @@
-import { expect, type Page, test } from "@playwright/test"
+import { expect, test } from "@playwright/test"
+import { api, apiPage, deleteAll } from "./utils/api"
 
 /**
  * Flows can be taken off the engine and put back, and what a node prints — or
@@ -11,8 +12,6 @@ test.use({ storageState: "playwright/.auth/user.json" })
 
 test.describe.configure({ mode: "serial" })
 
-const apiUrl = process.env.VITE_API_URL || "http://api.localhost"
-
 const PRINTING_NODE = `def process(params):
     print("sensor read 21.5 degrees")
     return {"reading": 21.5}
@@ -21,23 +20,12 @@ const BROKEN_NODE = `def process(reading, params):
     raise RuntimeError("downstream blew up")
 `
 
-async function api(
-  page: Page,
-  path: string,
-  init: Record<string, unknown> = {},
-) {
-  const token = await page.evaluate(() => localStorage.getItem("access_token"))
-  return page.request.fetch(`${apiUrl}/api/v1${path}`, {
-    ...init,
-    headers: { Authorization: `Bearer ${token}` },
-  })
-}
+test.afterAll(async ({ browser }) => {
+  await deleteAll(browser, [`/flows/${flowName}`])
+})
 
 test.beforeAll(async ({ browser }) => {
-  const page = await browser.newPage({
-    storageState: "playwright/.auth/user.json",
-  })
-  await page.goto("/")
+  const page = await apiPage(browser)
   await api(page, `/flows/${flowName}`, {
     method: "PUT",
     data: {
@@ -123,6 +111,4 @@ test("a flow can be paused and let go again", async ({ page }) => {
 
   await page.getByTestId("resume-flow").click()
   await expect(page.getByTestId("pause-flow")).toBeVisible()
-
-  await api(page, `/flows/${flowName}`, { method: "DELETE" })
 })
diff --git a/frontend/tests/utils/api.ts b/frontend/tests/utils/api.ts
new file mode 100644
index 0000000..deca937
--- /dev/null
+++ b/frontend/tests/utils/api.ts
@@ -0,0 +1,41 @@
+import type { Browser, Page } from "@playwright/test"
+
+/**
+ * Talking to the API directly, for the setup and teardown around a spec.
+ *
+ * The specs run against a development stack, so whatever they create has to go
+ * again — the same bargain the backend suite strikes with its throwaway
+ * database. What a spec leaves behind is in someone's flow list tomorrow.
+ */
+
+const authFile = "playwright/.auth/user.json"
+const apiUrl = process.env.VITE_API_URL || "http://api.localhost"
+
+/** Call the API as the logged-in user of *page*. */
+export async function api(
+  page: Page,
+  path: string,
+  init: Record<string, unknown> = {},
+) {
+  const token = await page.evaluate(() => localStorage.getItem("access_token"))
+  return page.request.fetch(`${apiUrl}/api/v1${path}`, {
+    ...init,
+    headers: { Authorization: `Bearer ${token}` },
+  })
+}
+
+/** An authenticated page for a `beforeAll`/`afterAll`, which get no `page`. */
+export async function apiPage(browser: Browser) {
+  const page = await browser.newPage({ storageState: authFile })
+  await page.goto("/")
+  return page
+}
+
+/** Delete the given API paths, whether or not they are still there. */
+export async function deleteAll(browser: Browser, paths: string[]) {
+  const page = await apiPage(browser)
+  for (const path of paths) {
+    await api(page, path, { method: "DELETE" })
+  }
+  await page.close()
+}