diff --git a/src/esmock.js b/src/esmock.js
index 3c359dc6..bba7405d 100644
--- a/src/esmock.js
+++ b/src/esmock.js
@@ -17,8 +17,8 @@ const esmockGo = opts => async (...args) => {
 }
 
 const purge = mockModule => mockModule
-  && /object|function/.test(typeof mockModule) && 'esmockKey' in mockModule
-  && esmockModule.purge(mockModule.esmockKey)
+  && /object|function/.test(typeof mockModule) && 'esmkTreeId' in mockModule
+  && esmockModule.purge(mockModule.esmkTreeId)
 
 const strict = Object.assign(esmockGo({ strict: true }), {
   purge, p: esmockGo({ strict: true, purge: false }) })
diff --git a/src/esmockCache.js b/src/esmockCache.js
index 386702b0..05342334 100644
--- a/src/esmockCache.js
+++ b/src/esmockCache.js
@@ -6,10 +6,10 @@ const esmockCache = {
   mockDefs: {}
 }
 
-const esmockKeySet = (key, keylong) => (
+const esmockTreeIdSet = (key, keylong) => (
   global.mockKeys[String(key)] = keylong)
 
-const esmockKeyGet = key => (
+const esmockTreeIdGet = key => (
   global.mockKeys[String(key)])
 
 const esmockCacheSet = (key, mockDef) => (
@@ -26,7 +26,7 @@ const esmockCacheResolvedPathIsESMSet = (mockPathFull, isesm) => (
 
 Object.assign(global, {
   esmockCacheGet,
-  esmockKeyGet,
+  esmockTreeIdGet,
   mockKeys: {}
 })
 
@@ -34,8 +34,8 @@ export {
   esmockCache as default,
   esmockCacheSet,
   esmockCacheGet,
-  esmockKeySet,
-  esmockKeyGet,
+  esmockTreeIdSet,
+  esmockTreeIdGet,
   esmockCacheResolvedPathIsESMGet,
   esmockCacheResolvedPathIsESMSet
 }
diff --git a/src/esmockLoader.js b/src/esmockLoader.js
index 15740a37..0b8518d2 100644
--- a/src/esmockLoader.js
+++ b/src/esmockLoader.js
@@ -4,14 +4,16 @@ import urlDummy from './esmockDummy.js'
 const [major, minor] = process.versions.node.split('.').map(it => +it)
 const isLT1612 = major < 16 || (major === 16 && minor < 12)
 
-const esmockGlobalsAndAfterRe = /\?esmockGlobals=.*/
-const esmockGlobalsAndBeforeRe = /.*\?esmockGlobals=/
-const esmockModuleKeysRe = /#-#esmockModuleKeys/
+const esmkgdefsAndAfterRe = /\?esmkgdefs=.*/
+const esmkgdefsAndBeforeRe = /.*\?esmkgdefs=/
+const esmkdefsRe = /#-#esmkdefs/
+const esmkTreeIdRe = /esmkTreeId=\d*/
+const esmkModuleIdRe = /esmkModuleId=([^&]*)/
+const esmkIdRe = /\?esmk=\d*/
 const exportNamesRe = /.*exportNames=(.*)/
-const esmockKeyRe = /esmockKey=\d*/
 const withHashRe = /.*#-#/
 const isesmRe = /isesm=true/
-const notfoundRe = /notfound=([^&]*)/
+const isnotfoundRe = /isfound=false/
 
 // new versions of node: when multiple loaders are used and context
 // is passed to nextResolve, the process crashes in a recursive call
@@ -30,49 +32,44 @@ const nextResolveCall = async (nextResolve, specifier, context) => (
 
 const resolve = async (specifier, context, nextResolve) => {
   const { parentURL } = context
-  const [esmockKeyParamSmall] =
-    (parentURL && parentURL.match(/\?esmk=\d*/)) || []
-  const esmockKeyLong = esmockKeyParamSmall
-    ? global.esmockKeyGet(esmockKeyParamSmall.split('=')[1])
+  const treeidspec = esmkIdRe.test(parentURL)
+    ? global.esmockTreeIdGet(parentURL.match(esmkIdRe)[0].split('=')[1])
     : parentURL
 
-  if (!esmockKeyRe.test(esmockKeyLong))
+  if (!esmkTreeIdRe.test(treeidspec))
     return nextResolveCall(nextResolve, specifier, context)
 
-  const [esmockKeyParam] = String(esmockKeyLong).match(esmockKeyRe)
-  const [keyUrl, keys] = esmockKeyLong.split(esmockModuleKeysRe)
-  const moduleGlobals = keyUrl && keyUrl.replace(esmockGlobalsAndBeforeRe, '')
+  const [treeid] = String(treeidspec).match(esmkTreeIdRe)
+  const [url, defs] = treeidspec.split(esmkdefsRe)
+  const gdefs = url && url.replace(esmkgdefsAndBeforeRe, '')
   // do not call 'nextResolve' for notfound modules
-  if (esmockKeyLong.includes(`notfound=${specifier}`)) {
-    const moduleKeyRe = new RegExp(
-      '.*file:///' + specifier + '(\\?' + esmockKeyParam + '(?:(?!#-#).)*).*')
-    const moduleKey = (
-      moduleGlobals.match(moduleKeyRe) || keys.match(moduleKeyRe) || [])[1]
-    if (moduleKey) {
+  if (treeidspec.includes(`esmkModuleId=${specifier}&isfound=false`)) {
+    const moduleIdRe = new RegExp(
+      '.*file:///' + specifier + '(\\?' + treeid + '(?:(?!#-#).)*).*')
+    const moduleId = (
+      gdefs.match(moduleIdRe) || defs.match(moduleIdRe) || [])[1]
+    if (moduleId) {
       return {
         shortCircuit: true,
-        url: urlDummy + moduleKey
+        url: urlDummy + moduleId
       }
     }
   }
 
   const resolved = await nextResolveCall(nextResolve, specifier, context)
   const resolvedurl = decodeURI(resolved.url)
-  const moduleKeyRe = new RegExp(
-    '.*(' + resolvedurl + '\\?' + esmockKeyParam + '(?:(?!#-#).)*).*')
-  const moduleKeyChild = moduleKeyRe.test(keys)
-        && keys.replace(moduleKeyRe, '$1')
-  const moduleKeyGlobal = moduleKeyRe.test(moduleGlobals)
-        && moduleGlobals.replace(moduleKeyRe, '$1')
-
-  const moduleKey = moduleKeyChild || moduleKeyGlobal
-  if (moduleKey) {
-    resolved.url = isesmRe.test(moduleKey)
-      ? moduleKey
-      : urlDummy + '#-#' + moduleKey
-  } else if (moduleGlobals && moduleGlobals !== '0') {
+  const moduleIdRe = new RegExp(
+    '.*(' + resolvedurl + '\\?' + treeid + '(?:(?!#-#).)*).*')
+  const moduleId =
+    moduleIdRe.test(defs) && defs.replace(moduleIdRe, '$1') ||
+    moduleIdRe.test(gdefs) && gdefs.replace(moduleIdRe, '$1')
+  if (moduleId) {
+    resolved.url = isesmRe.test(moduleId)
+      ? moduleId
+      : urlDummy + '#-#' + moduleId
+  } else if (gdefs && gdefs !== '0') {
     if (!resolved.url.startsWith('node:')) {
-      resolved.url += '?esmockGlobals=' + moduleGlobals
+      resolved.url += '?esmkgdefs=' + gdefs
     }
   }
 
@@ -80,14 +77,14 @@ const resolve = async (specifier, context, nextResolve) => {
 }
 
 const load = async (url, context, nextLoad) => {
-  if (esmockModuleKeysRe.test(url)) // parent of mocked modules
+  if (esmkdefsRe.test(url)) // parent of mocked modules
     return nextLoad(url, context)
 
-  url = url.replace(esmockGlobalsAndAfterRe, '')
+  url = url.replace(esmkgdefsAndAfterRe, '')
   if (url.startsWith(urlDummy)) {
     url = url.replace(withHashRe, '')
-    if (notfoundRe.test(url))
-      url = url.replace(urlDummy, `file:///${url.match(notfoundRe)[1]}`)
+    if (isnotfoundRe.test(url))
+      url = url.replace(urlDummy, `file:///${url.match(esmkModuleIdRe)[1]}`)
   }
 
   const exportedNames = exportNamesRe.test(url) &&
diff --git a/src/esmockModule.js b/src/esmockModule.js
index 84d6a12a..bb74babd 100644
--- a/src/esmockModule.js
+++ b/src/esmockModule.js
@@ -2,8 +2,8 @@ import fs from 'fs'
 import resolvewith from 'resolvewithplus'
 
 import {
-  esmockKeySet,
-  esmockKeyGet,
+  esmockTreeIdSet,
+  esmockTreeIdGet,
   esmockCacheSet,
   esmockCacheResolvedPathIsESMGet,
   esmockCacheResolvedPathIsESMSet
@@ -12,24 +12,22 @@ import {
 const isObj = o => typeof o === 'object' && o
 const isDefaultIn = o => isObj(o) && 'default' in o
 const isDirPathRe = /^\.?\.?([a-zA-Z]:)?(\/|\\)/
-const esmockNextKey = ((key = 0) => () => ++key)()
+const esmockNextId = ((id = 0) => () => ++id)()
 
 const esmockModuleIdNotFoundError = (moduleId, parent) => new Error(
   `invalid moduleId: "${moduleId}" (used by ${parent})`
     .replace(process.cwd(), '.')
     .replace(process.env.HOME, '~'))
 
-const esmockModuleMergeDefault = (defLive, defMock) =>
-  (isObj(defLive) && isObj(defMock))
-    ? Object.assign({}, defLive, defMock)
-    : defMock
+const esmockModuleMergeDefault = (defLive, def) =>
+  (isObj(defLive) && isObj(def)) ? Object.assign({}, defLive, def) : def
 
-const esmockModuleApply = (defLive, defMock, fileURL) => {
-  const def = Object.assign({}, defLive || {}, {
+const esmockModuleApply = (defLive, def, fileURL) => {
+  def = Object.assign({}, defLive || {}, {
     default: esmockModuleMergeDefault(
       isDefaultIn(defLive) && defLive.default,
-      isDefaultIn(defMock) ? defMock.default : defMock)
-  }, defMock)
+      isDefaultIn(def) ? def.default : def)
+  }, def)
 
   // if safe, an extra "default.default" is added for compatibility with
   // babel-generated dist cjs files which also define "default.default"
@@ -60,7 +58,7 @@ const esmockModuleIsESM = (fileURL, isesm) => {
 
 // return the default value directly, so that the esmock caller
 // does not need to lookup default as in "esmockedValue.default"
-const esmockModuleImportedSanitize = (imported, esmockKey) => {
+const esmockModuleImportedSanitize = (imported, esmkTreeId) => {
   const importedDefault = isDefaultIn(imported) && imported.default
 
   if (/boolean|string|number/.test(typeof importedDefault))
@@ -68,30 +66,29 @@ const esmockModuleImportedSanitize = (imported, esmockKey) => {
   
   // ex, non-extensible "[object Module]": import * as fs from 'fs'; export fs;
   return Object.isExtensible(importedDefault)
-    ? Object.assign(importedDefault, imported, { esmockKey })
-    : Object.assign({}, importedDefault, imported, { esmockKey })
+    ? Object.assign(importedDefault, imported, { esmkTreeId })
+    : Object.assign({}, importedDefault, imported, { esmkTreeId })
 }
 
-const esmockModuleImportedPurge = modulePathKey => {
+const esmockModuleImportedPurge = treeid => {
   const purgeKey = key => key === 'null' || esmockCacheSet(key, null)
-  const longKey = esmockKeyGet(modulePathKey.split('esmk=')[1])
-  const [url, keys] = longKey.split('#-#esmockModuleKeys=')
+  const longKey = esmockTreeIdGet(treeid.split('esmk=')[1])
+  const [url, keys] = longKey.split('#-#esmkdefs=')
 
   String(keys).split('#-#').forEach(purgeKey)
-  String(url.split('esmockGlobals=')[1]).split('#-#').forEach(purgeKey)
+  String(url.split('esmkgdefs=')[1]).split('#-#').forEach(purgeKey)
 }
 
-const esmockModuleCreate = async (esmockKey, key, fileURL, defMock, opt) => {
-  const isesm = esmockModuleIsESM(fileURL)
-  const def = esmockModuleApply(
-    opt.strict || !fileURL || await import(fileURL), defMock, fileURL)
-  const mockExportNames = Object.keys(def).sort().join()
-  const mockModuleKey = (fileURL || 'file:///' + key) + '?' + [
-    'esmockKey=' + esmockKey,
-    'esmockModuleKey=' + key,
-    'isesm=' + isesm,
-    fileURL ? 'found' : 'notfound=' + key,
-    mockExportNames ? 'exportNames=' + mockExportNames : 'exportNone'
+const esmockModuleCreate = async (treeid, def, id, fileURL, opt) => {
+  def = esmockModuleApply(
+    opt.strict || !fileURL || await import(fileURL), def, fileURL)
+
+  const mockModuleKey = (fileURL || 'file:///' + id) + '?' + [
+    'esmkTreeId=' + treeid,
+    'esmkModuleId=' + id,
+    'isfound=' + Boolean(fileURL),
+    'isesm=' + esmockModuleIsESM(fileURL),
+    'exportNames=' + Object.keys(def).sort().join()
   ].join('&')
 
   esmockCacheSet(mockModuleKey, def)
@@ -99,20 +96,20 @@ const esmockModuleCreate = async (esmockKey, key, fileURL, defMock, opt) => {
   return mockModuleKey
 }
 
-const esmockModuleId = async (parent, key, defs, ids, opt, mocks, id) => {
+const esmockModuleId = async (parent, treeid, defs, ids, opt, mocks, id) => {
   ids = ids || Object.keys(defs)
   id = ids[0]
   mocks = mocks || []
 
   if (!id) return mocks
 
-  const mockedPathFull = resolvewith(id, parent)
-  if (!mockedPathFull && opt.isModuleNotFoundError !== false)
+  const fileURL = resolvewith(id, parent)
+  if (!fileURL && opt.isModuleNotFoundError !== false)
     throw esmockModuleIdNotFoundError(id, parent)
 
-  mocks.push(await esmockModuleCreate(key, id, mockedPathFull, defs[id], opt))
+  mocks.push(await esmockModuleCreate(treeid, defs[id], id, fileURL, opt))
 
-  return esmockModuleId(parent, key, defs, ids.slice(1), opt, mocks)
+  return esmockModuleId(parent, treeid, defs, ids.slice(1), opt, mocks)
 }
 
 const esmockModule = async (moduleId, parent, defs, gdefs, opt) => {
@@ -120,18 +117,17 @@ const esmockModule = async (moduleId, parent, defs, gdefs, opt) => {
   if (!moduleFileURL)
     throw esmockModuleIdNotFoundError(moduleId, parent)
 
-  const esmockKey = typeof opt.key === 'number' ? opt.key : esmockNextKey()
-  const esmockKeyLong = moduleFileURL + '?' +
-    'key=:esmockKey?esmockGlobals=:esmockGlobals#-#esmockModuleKeys=:moduleKeys'
-      .replace(/:esmockKey/, esmockKey)
-      .replace(/:esmockGlobals/, gdefs && (await esmockModuleId(
-        parent, esmockKey, gdefs, Object.keys(gdefs), opt)).join('#-#') || 0)
-      .replace(/:moduleKeys/, defs && (await esmockModuleId(
-        parent, esmockKey, defs, Object.keys(defs), opt)).join('#-#') || 0)
+  const treeid = typeof opt.id === 'number' ? opt.id : esmockNextId()
+  const treeidspec = `${moduleFileURL}?key=${treeid}?` + [
+    'esmkgdefs=' + (gdefs && (await esmockModuleId(
+      parent, treeid, gdefs, Object.keys(gdefs), opt)).join('#-#') || 0),
+    'esmkdefs=', (defs && (await esmockModuleId(
+      parent, treeid, defs, Object.keys(defs), opt)).join('#-#') || 0)
+  ].join('#-#')
 
-  esmockKeySet(String(esmockKey), esmockKeyLong)
+  esmockTreeIdSet(String(treeid), treeidspec)
 
-  return moduleFileURL + `?esmk=${esmockKey}`
+  return moduleFileURL + `?esmk=${treeid}`
 }
 
 export default Object.assign(esmockModule, {
diff --git a/tests/tests-ava/spec/esmock.ava.spec.js b/tests/tests-ava/spec/esmock.ava.spec.js
index 8cfc5cd4..5ae1cf64 100644
--- a/tests/tests-ava/spec/esmock.ava.spec.js
+++ b/tests/tests-ava/spec/esmock.ava.spec.js
@@ -128,12 +128,12 @@ test('should purge local and global mocks', async t => {
         : filepath
     }
   }, {
-    key: 999
+    id: 999
   })
 
   const keys = Object
     .keys(esmockCache.mockDefs)
-    .filter(key => /esmockKey=999/.test(key))
+    .filter(key => /esmkTreeId=999/.test(key))
 
   t.truthy(keys.length)
   t.true(keys.every(key => esmockCache.mockDefs[key] === null))
@@ -309,8 +309,8 @@ test('mocks inline `async import("name")`', async t => {
       filePath: 'filePath'
     }))
 
-  const [, key] = writeJSConfigFile.esmockKey.match(/esmk=(\d*)/)
-  const keyRe = new RegExp(`esmockKey=${key}[^d]`)
+  const [, key] = writeJSConfigFile.esmkTreeId.match(/esmk=(\d*)/)
+  const keyRe = new RegExp(`esmkTreeId=${key}[^d]`)
 
   const moduleKeys = Object.keys(esmockCache.mockDefs)
     .filter(moduleKey => keyRe.test(moduleKey))
@@ -401,3 +401,4 @@ test('should not error when mocked file has space in path', async t => {
 
   t.is(main.wild, 'tamed')
 })
+
diff --git a/tests/tests-node/esmock.node.test.js b/tests/tests-node/esmock.node.test.js
index 93553775..92179d88 100644
--- a/tests/tests-node/esmock.node.test.js
+++ b/tests/tests-node/esmock.node.test.js
@@ -137,12 +137,12 @@ test('should purge local and global mocks', async () => {
         : filepath
     }
   }, {
-    key: 999
+    id: 999
   })
 
   const keys = Object
     .keys(esmockCache.mockDefs)
-    .filter(key => /esmockKey=999/.test(key))
+    .filter(key => /esmkTreeId=999/.test(key))
 
   assert.ok(keys.length)
   assert.ok(keys.every(key => esmockCache.mockDefs[key] === null))
@@ -323,8 +323,8 @@ test('mocks inline `async import("name")`', async () => {
       filePath: 'filePath'
     }))
 
-  const [, key] = writeJSConfigFile.esmockKey.match(/esmk=(\d*)/)
-  const keyRe = new RegExp(`esmockKey=${key}[^d]`)
+  const [, key] = writeJSConfigFile.esmkTreeId.match(/esmk=(\d*)/)
+  const keyRe = new RegExp(`esmkTreeId=${key}[^d]`)
 
   const moduleKeys = Object.keys(esmockCache.mockDefs)
     .filter(moduleKey => keyRe.test(moduleKey))
diff --git a/tests/tests-uvu/esmock.uvu.spec.js b/tests/tests-uvu/esmock.uvu.spec.js
index 63e392e7..a0f15952 100644
--- a/tests/tests-uvu/esmock.uvu.spec.js
+++ b/tests/tests-uvu/esmock.uvu.spec.js
@@ -97,12 +97,12 @@ test('should purge local and global mocks', async () => {
         : filepath
     }
   }, {
-    key: 999
+    id: 999
   })
 
   const keys = Object
     .keys(esmockCache.mockDefs)
-    .filter(key => /esmockKey=999/.test(key))
+    .filter(key => /esmkTreeId=999/.test(key))
 
   assert.ok(keys.length)
   assert.ok(keys.every(key => esmockCache.mockDefs[key] === null))
@@ -278,8 +278,8 @@ test('mocks inline `async import("name")`', async () => {
       filePath: 'filePath'
     }))
 
-  const [, key] = writeJSConfigFile.esmockKey.match(/esmk=(\d*)/)
-  const keyRe = new RegExp(`esmockKey=${key}[^d]`)
+  const [, key] = writeJSConfigFile.esmkTreeId.match(/esmk=(\d*)/)
+  const keyRe = new RegExp(`esmkTreeId=${key}[^d]`)
 
   const moduleKeys = Object.keys(esmockCache.mockDefs)
     .filter(moduleKey => keyRe.test(moduleKey))