diff --git a/.gitignore b/.gitignore
index 6bf7fdc08f..0f63580947 100644
--- a/.gitignore
+++ b/.gitignore
@@ -50,6 +50,7 @@ tests/simple-long-path/long-src-path
 # is linked to the temp dir of the os
 e2e/__workdir_synlink__
 **/.ts-jest-e2e.json
+.ts-jest-digest
 # while refactoring...
 old/
 
diff --git a/.npmignore b/.npmignore
index 9168b0e8cf..2c9e8e1826 100644
--- a/.npmignore
+++ b/.npmignore
@@ -74,3 +74,6 @@ tslint.json
 docs
 
 commitlint.config.js
+
+# ensure we do not omit the digest
+!.ts-jest-digest
diff --git a/package.json b/package.json
index cd6e364c61..e9eab1b89d 100644
--- a/package.json
+++ b/package.json
@@ -8,9 +8,10 @@
   "scripts": {
     "prebuild": "node scripts/clean-dist.js",
     "build": "tsc -p tsconfig.build.json",
+    "postbuild": "node scripts/post-build.js",
     "build:watch": "tsc -p tsconfig.build.json -w",
     "clean": "node scripts/clean.js",
-    "pretest": "run-s typecheck lint",
+    "pretest": "npm run lint",
     "test": "run-s -s test:e2e \"test:unit -- {@}\" --",
     "test:prepare": "npm run test:e2e -- --prepareOnly",
     "test:e2e": "node scripts/e2e.js",
diff --git a/scripts/e2e.js b/scripts/e2e.js
index 3d988bf653..605b7b4523 100755
--- a/scripts/e2e.js
+++ b/scripts/e2e.js
@@ -8,7 +8,7 @@ const path = require('path')
 const Paths = require('./lib/paths')
 const { createHash } = require('crypto')
 const logger = require('./lib/logger')
-const { createBundle, packageDigest } = require('./lib/bundle')
+const { createBundle, readPackageDigest } = require('./lib/bundle')
 const npm = require('./lib/npm')
 
 const configFile = path.join(Paths.e2eRootDir, 'jest.config.js')
@@ -49,8 +49,7 @@ function setupE2e() {
   )
 
   // get the hash of the bundle (to know if we should install it again or not)
-  // we need to compute it ourselfs as the npm pack creates different tgz even tho content has not changed
-  const bundleHash = packageDigest(bundle)
+  const bundleHash = readPackageDigest()
   log('ts-jest digest:', bundleHash)
 
   // ensure directory exists before copying over
diff --git a/scripts/lib/bundle.js b/scripts/lib/bundle.js
index a70b2e08b7..2c32874c38 100644
--- a/scripts/lib/bundle.js
+++ b/scripts/lib/bundle.js
@@ -1,8 +1,8 @@
 const npm = require('./npm')
 const logger = require('./logger')
-const { rootDir } = require('./paths')
+const { rootDir, pkgDigestFile } = require('./paths')
 const { join, resolve } = require('path')
-const { readFileSync, statSync } = require('fs')
+const { readFileSync, statSync, writeFileSync, existsSync } = require('fs-extra')
 const { createHash } = require('crypto')
 const { sync: globIgnore } = require('glob-gitignore')
 
@@ -19,7 +19,11 @@ function createBundle(log = logger.log.bind(logger)) {
   return join(rootDir, res.stdout.toString().trim())
 }
 
-function packageDigest() {
+function readPackageDigest() {
+  return existsSync(pkgDigestFile) ? readFileSync(pkgDigestFile, 'utf8') : undefined
+}
+
+function computePackageDigest(noWriteFile = false) {
   const files = globIgnore(join(rootDir, '**'), {
     ignore: readFileSync(join(rootDir, '.npmignore'))
       .toString('utf8')
@@ -28,14 +32,19 @@ function packageDigest() {
   })
   const hash = createHash('sha1')
   files.sort().forEach(file => {
-    if (statSync(file).isDirectory()) return
+    if (file === pkgDigestFile || statSync(file).isDirectory()) return
     hash.update(readFileSync(resolve(file)))
     hash.update('\x00')
   })
-  return hash.digest('hex')
+  const digest = hash.digest('hex')
+  if (!noWriteFile) {
+    writeFileSync(pkgDigestFile, digest, 'utf8')
+  }
+  return digest
 }
 
 module.exports = {
   createBundle,
-  packageDigest,
+  computePackageDigest,
+  readPackageDigest,
 }
diff --git a/scripts/lib/paths.d.ts b/scripts/lib/paths.d.ts
index 6a346dcd24..4c6b0e3768 100644
--- a/scripts/lib/paths.d.ts
+++ b/scripts/lib/paths.d.ts
@@ -1,4 +1,5 @@
 declare const rootDir: string
+declare const pkgDigestFile: string
 declare const e2eSourceDir: string
 declare const e2eRootDir: string
 declare const e2eWorkDir: string
@@ -11,6 +12,7 @@ declare const e2eTestsDir: string
 
 export {
   rootDir,
+  pkgDigestFile,
   e2eSourceDir,
   e2eRootDir,
   e2eWorkDir,
diff --git a/scripts/lib/paths.js b/scripts/lib/paths.js
index 8abc889a5a..26907635b1 100644
--- a/scripts/lib/paths.js
+++ b/scripts/lib/paths.js
@@ -2,6 +2,7 @@ const path = require('path')
 const os = require('os')
 
 const rootDir = path.resolve(__dirname, '..', '..')
+const pkgDigestFile = path.join(rootDir, '.ts-jest-digest')
 const distDir = path.join(rootDir, 'dist')
 const testsRootDir = path.join(rootDir, 'tests')
 const e2eRootDir = path.join(rootDir, 'e2e')
@@ -15,6 +16,7 @@ const e2eWorkTemplatesDir = path.join(e2eWorkDir, '__templates__')
 const e2eWotkDirLink = path.join(e2eRootDir, '__workdir_synlink__')
 
 module.exports = {
+  pkgDigestFile,
   rootDir,
   e2eSourceDir,
   e2eRootDir,
diff --git a/scripts/post-build.js b/scripts/post-build.js
new file mode 100644
index 0000000000..c88e7b5796
--- /dev/null
+++ b/scripts/post-build.js
@@ -0,0 +1,3 @@
+const { computePackageDigest } = require('./lib/bundle')
+
+computePackageDigest()
diff --git a/src/__mocks__/index.ts b/src/__mocks__/index.ts
new file mode 100644
index 0000000000..54c4bda3d1
--- /dev/null
+++ b/src/__mocks__/index.ts
@@ -0,0 +1,6 @@
+export const version = '1.2.3-test.0'
+export const digest = 'a0d51ca854194df8191d0e65c0ca4730f510f332'
+export const createTransformer = jest.fn()
+export const jestPreset = { jestPreset: true }
+export const createJestPreset = jest.fn()
+export const pathsToModuleNameMapper = jest.fn()
diff --git a/src/config/config-set.spec.ts b/src/config/config-set.spec.ts
index e5a7bc3988..a357fc9bbe 100644
--- a/src/config/config-set.spec.ts
+++ b/src/config/config-set.spec.ts
@@ -2,7 +2,7 @@ import { testing } from 'bs-logger'
 import { resolve } from 'path'
 import ts, { Diagnostic, ModuleKind, ScriptTarget } from 'typescript'
 
-import { version as currentVersion } from '../../package.json'
+import * as _myModule from '..'
 import * as fakers from '../__helpers__/fakers'
 import { logTargetMock, mocked } from '../__helpers__/mocks'
 import { TsJestGlobalOptions } from '../types'
@@ -12,8 +12,10 @@ import { normalizeSlashes } from '../util/normalize-slashes'
 import { ConfigSet, IGNORE_DIAGNOSTIC_CODES, MATCH_NOTHING } from './config-set'
 
 jest.mock('../util/backports')
+jest.mock('../index')
 
 const backports = mocked(_backports)
+const myModule = mocked(_myModule)
 
 backports.backportJestConfig.mockImplementation((_, config) => ({
   ...config,
@@ -385,7 +387,7 @@ describe('versions', () => {
     it('should return correct version map', () => {
       expect(createConfigSet().versions).toEqual({
         jest: pkgVersion('jest'),
-        'ts-jest': currentVersion,
+        'ts-jest': myModule.version,
         typescript: pkgVersion('typescript'),
       })
     })
@@ -397,13 +399,19 @@ describe('versions', () => {
         'babel-core': pkgVersion('babel-core'),
         'babel-jest': pkgVersion('babel-jest'),
         jest: pkgVersion('jest'),
-        'ts-jest': currentVersion,
+        'ts-jest': myModule.version,
         typescript: pkgVersion('typescript'),
       })
     })
   })
 }) // versions
 
+describe('tsJestDigest', () => {
+  it('should be the package digest', () => {
+    expect(createConfigSet().tsJestDigest).toBe(myModule.digest)
+  })
+}) // tsJestDigest
+
 describe('tsconfig', () => {
   it('should return input tsconfig', () => {
     const cs = createConfigSet({ tsJestConfig: { tsConfig: { target: 'ES6' } } as any })
@@ -468,8 +476,9 @@ describe('cacheKey', () => {
     const val = cs.jsonValue.value
     delete val.versions
     cs.jsonValue.value = val
+    // digest is mocked in src/__mocks__/index.ts
     expect(cs.cacheKey).toMatchInlineSnapshot(
-      `"{\\"jest\\":{\\"__backported\\":true,\\"globals\\":{}},\\"transformers\\":[\\"hoisting-jest-mock@1\\"],\\"tsJest\\":{\\"compiler\\":\\"typescript\\",\\"diagnostics\\":{\\"ignoreCodes\\":[6059,18002,18003],\\"pretty\\":true,\\"throws\\":true},\\"isolatedModules\\":false,\\"transformers\\":[]},\\"tsconfig\\":{\\"compilerOptions\\":{}}}"`,
+      `"{\\"digest\\":\\"a0d51ca854194df8191d0e65c0ca4730f510f332\\",\\"jest\\":{\\"__backported\\":true,\\"globals\\":{}},\\"transformers\\":[\\"hoisting-jest-mock@1\\"],\\"tsJest\\":{\\"compiler\\":\\"typescript\\",\\"diagnostics\\":{\\"ignoreCodes\\":[6059,18002,18003],\\"pretty\\":true,\\"throws\\":true},\\"isolatedModules\\":false,\\"transformers\\":[]},\\"tsconfig\\":{\\"declaration\\":false,\\"inlineSourceMap\\":false,\\"inlineSources\\":true,\\"module\\":1,\\"noEmit\\":false,\\"outDir\\":\\"$$ts-jest$$\\",\\"removeComments\\":false,\\"sourceMap\\":true,\\"target\\":1}}"`,
     )
   })
 }) // cacheKey
@@ -479,13 +488,15 @@ describe('jsonValue', () => {
     const cs = createConfigSet({ tsJestConfig: { tsConfig: false } as any })
     const val = cs.jsonValue.valueOf()
     expect(cs.toJSON()).toEqual(val)
-    // it will change each time we upgrade and we tested those in the `version` block
+    // it will change each time we upgrade – we tested those in the `version` block
     expect(val.versions).toEqual(cs.versions)
     delete val.versions
 
+    // digest is mocked in src/__mocks__/index.ts
     expect(val).toMatchInlineSnapshot(`
 Object {
   "babel": undefined,
+  "digest": "a0d51ca854194df8191d0e65c0ca4730f510f332",
   "jest": Object {
     "__backported": true,
     "globals": Object {},
@@ -511,7 +522,16 @@ Object {
     "tsConfig": undefined,
   },
   "tsconfig": Object {
-    "compilerOptions": Object {},
+    "configFilePath": undefined,
+    "declaration": false,
+    "inlineSourceMap": false,
+    "inlineSources": true,
+    "module": 1,
+    "noEmit": false,
+    "outDir": "$$ts-jest$$",
+    "removeComments": false,
+    "sourceMap": true,
+    "target": 1,
   },
 }
 `)
diff --git a/src/config/config-set.ts b/src/config/config-set.ts
index 00acbfafc9..4d1c1debfd 100644
--- a/src/config/config-set.ts
+++ b/src/config/config-set.ts
@@ -23,7 +23,7 @@ import {
   SourceFile,
 } from 'typescript'
 
-import { version as myVersion } from '..'
+import { digest as MY_DIGEST, version as MY_VERSION } from '..'
 import { createCompiler } from '../compiler'
 import { internals as internalAstTransformers } from '../transformers'
 import {
@@ -229,7 +229,7 @@ export class ConfigSet {
         map[name] = getPackageVersion(name) || '-'
         return map
       },
-      { 'ts-jest': myVersion } as Record<string, string>,
+      { 'ts-jest': MY_VERSION } as Record<string, string>,
     )
   }
 
@@ -438,10 +438,10 @@ export class ConfigSet {
         compiler: this.tsJest.compiler,
         compilerOptions: this.typescript.options,
         isolatedModules: this.tsJest.isolatedModules,
-        ignoreDiagnostics: this.tsJest.diagnostics.ignoreCodes,
+        diagnostics: this.tsJest.diagnostics,
       }),
     )
-    const res = join(this.jest.cacheDirectory, `ts-jest-${cacheSuffix}`)
+    const res = join(this.jest.cacheDirectory, 'ts-jest', cacheSuffix.substr(0, 2), cacheSuffix.substr(2))
     logger.debug({ cacheDirectory: res }, `will use file caching`)
     return res
   }
@@ -489,6 +489,11 @@ export class ConfigSet {
     return !!process.env.TS_JEST_DOCTOR
   }
 
+  @Memoize()
+  get tsJestDigest(): string {
+    return MY_DIGEST
+  }
+
   /**
    * @internal
    */
@@ -505,11 +510,12 @@ export class ConfigSet {
 
     return new JsonableValue({
       versions: this.versions,
+      digest: this.tsJestDigest,
       transformers: this.astTransformers.map(t => `${t.name}@${t.version}`),
       jest,
       tsJest: this.tsJest,
       babel: this.babel,
-      tsconfig: this.tsconfig,
+      tsconfig: this.typescript.options,
     })
   }
 
diff --git a/src/index.ts b/src/index.ts
index 76e8775a37..15806be569 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,3 +1,6 @@
+import { readFileSync } from 'fs'
+import { resolve } from 'path'
+
 import { createJestPreset } from './config/create-jest-preset'
 import { pathsToModuleNameMapper } from './config/paths-to-module-name-mapper'
 import { TsJestTransformer } from './ts-jest-transformer'
@@ -6,6 +9,7 @@ import { VersionCheckers } from './util/version-checkers'
 
 // tslint:disable-next-line:no-var-requires
 export const version: string = require('../package.json').version
+export const digest: string = readFileSync(resolve(__dirname, '..', '.ts-jest-digest'), 'utf8')
 
 let transformer!: TsJestTransformer
 function defaultTransformer(): TsJestTransformer {