diff --git a/src/member-api.js b/src/member-api.js
index 75627555..f359fb04 100644
--- a/src/member-api.js
+++ b/src/member-api.js
@@ -89,6 +89,7 @@ export class MemberApi extends TypedEmitter {
    * @param {import('./roles.js').RoleIdForNewInvite} opts.roleId
    * @param {string} [opts.roleName]
    * @param {string} [opts.roleDescription]
+   * @param {Buffer} [opts.__testOnlyInviteId] Hard-code the invite ID. Only for tests.
    * @returns {Promise<(
    *   typeof InviteResponse_Decision.ACCEPT |
    *   typeof InviteResponse_Decision.REJECT |
@@ -97,7 +98,12 @@ export class MemberApi extends TypedEmitter {
    */
   async invite(
     deviceId,
-    { roleId, roleName = ROLES[roleId]?.name, roleDescription }
+    {
+      roleId,
+      roleName = ROLES[roleId]?.name,
+      roleDescription,
+      __testOnlyInviteId,
+    }
   ) {
     assert(isRoleIdForNewInvite(roleId), 'Invalid role ID for new invite')
     assert(
@@ -120,7 +126,7 @@ export class MemberApi extends TypedEmitter {
 
       abortSignal.throwIfAborted()
 
-      const inviteId = crypto.randomBytes(32)
+      const inviteId = __testOnlyInviteId || crypto.randomBytes(32)
       const projectId = projectKeyToId(this.#projectKey)
       const projectInviteId = projectKeyToProjectInviteId(this.#projectKey)
       const project = await this.#dataTypes.project.getByDocId(projectId)
diff --git a/test-e2e/utils.js b/test-e2e/utils.js
index 99c48e03..e5695537 100644
--- a/test-e2e/utils.js
+++ b/test-e2e/utils.js
@@ -7,13 +7,13 @@ import { fork } from 'node:child_process'
 import { createRequire } from 'node:module'
 import { fileURLToPath } from 'node:url'
 import * as v8 from 'node:v8'
+import { pEvent } from 'p-event'
 
 import { MapeoManager, roles } from '../src/index.js'
 import { kManagerReplicate, kRPC } from '../src/mapeo-manager.js'
-import { once } from 'node:events'
 import { generate } from '@mapeo/mock-data'
 import { valueOf } from '../src/utils.js'
-import { randomInt } from 'node:crypto'
+import { randomBytes, randomInt } from 'node:crypto'
 import { temporaryFile, temporaryDirectory } from 'tempy'
 import fsPromises from 'node:fs/promises'
 import { kSyncState } from '../src/sync/sync-api.js'
@@ -100,18 +100,25 @@ export async function invite({
   const promises = []
 
   for (const invitee of invitees) {
+    const inviteId = randomBytes(32)
     promises.push(
       invitorProject.$member.invite(invitee.deviceId, {
         roleId,
         roleName,
+        __testOnlyInviteId: inviteId,
       })
     )
     promises.push(
-      once(invitee.invite, 'invite-received').then(async ([invite]) => {
+      (async () => {
+        const invite = await pEvent(
+          invitee.invite,
+          'invite-received',
+          (invite) => Buffer.from(invite.inviteId, 'hex').equals(inviteId)
+        )
         await (reject
           ? invitee.invite.reject(invite)
           : invitee.invite.accept(invite))
-      })
+      })()
     )
   }