diff --git a/flaska.mjs b/flaska.mjs
index a0bd2d1..11725d1 100644
--- a/flaska.mjs
+++ b/flaska.mjs
@@ -341,11 +341,6 @@ export class Flaska {
     this._onreserror = handler
   }
 
-  onerror(handler) {
-    assertIsHandler(handler, 'onerror()')
-    this._onerror = handler
-  }
-
   before(handler) {
     assertIsHandler(handler, 'before()')
     this._before.push(handler)
@@ -427,6 +422,18 @@ export class Flaska {
 
   requestStartInternal(ctx) {
     let route = this.routers[ctx.method].match(ctx.url)
+    if (!route) {
+      let middle = this._on404(ctx)
+      if (middle && middle.then) {
+        return middle.then(() => {
+          this.requestEnd(null, ctx)
+        }, err => {
+          this.requestEnd(err, ctx)
+        })
+      }
+      return this.requestEnd(null, ctx)
+    }
+
     ctx.params = route.params
 
     if (route.middlewares.length) {
@@ -467,7 +474,11 @@ export class Flaska {
 
   requestEnd(err, ctx) {
     if (err) {
-      this._onerror(err, ctx)
+      try {
+        this._onerror(err, ctx)
+      } catch (err) {
+        this._backuperror(err, ctx)
+      }
     }
     if (ctx.res.writableEnded) {
       return
diff --git a/test.mjs b/test.mjs
index 4758d71..80727e3 100644
--- a/test.mjs
+++ b/test.mjs
@@ -4,18 +4,11 @@ const port = 51024
 const flaska = new Flaska({}, )
 
 flaska.get('/', function(ctx) {
-  return new Promise(function(res, rej) {
-    ctx.body = { status: true }
-    setTimeout(res, 1000)
-  })
+  ctx.body = { status: true }
 })
 
-flaska.after(function(ctx) {
-  if (ctx.aborted) {
-    process.stdout.write("A")
-  } else {
-    process.stdout.write(".")
-  }
+flaska.get('/error', function(ctx) {
+  process.exit(1)
 })
 
 flaska.listen(port, function() {
diff --git a/test/flaska.in.test.mjs b/test/flaska.in.test.mjs
index 6d219da..8930ac3 100644
--- a/test/flaska.in.test.mjs
+++ b/test/flaska.in.test.mjs
@@ -274,6 +274,126 @@ t.describe('#requestStart()', function() {
     }), createRes())
   })
 
+  t.test('calls 404 if route handler is not found', function(cb) {
+    const on404Error = spy()
+
+    let handler = function() {
+      throw new Error('should not be called')
+    }
+    
+    let flaska = new Flaska({}, faker)
+    flaska.on404(on404Error)
+    flaska.get('/test', function() { throw new Error('should not be called') })
+    flaska.compile()
+
+    flaska.requestEnd = function(err, ctx) {
+      if (err) return cb(err)
+
+      try {
+        assert.ok(ctx)
+        assert.strictEqual(on404Error.callCount, 1)
+        assert.strictEqual(on404Error.firstCall[0], ctx)
+        cb()
+      } catch (err) { cb(err) }
+    }
+
+    flaska.requestStart(createReq({
+      url: '/nope',
+      method: 'GET',
+    }), createRes())
+  })
+  
+  t.test('calls 404 if route handler is not found and supports promise', function(cb) {
+    let checkCtx = null
+    const assertError = new Error('should be seen')
+    const on404Error = function(ctx) {
+      checkCtx = ctx
+      return Promise.resolve().then(function() { return Promise.reject(assertError) })
+    }
+    
+    let flaska = new Flaska({}, faker)
+    flaska.on404(on404Error)
+    flaska.get('/test', function() { throw new Error('should not be called') })
+    flaska.compile()
+
+    flaska.requestEnd = function(err, ctx) {
+      if (err && err !== assertError) return cb(err)
+
+      try {
+        assert.ok(err)
+        assert.ok(ctx)
+        assert.strictEqual(ctx, checkCtx)
+        assert.strictEqual(err, assertError)
+        cb()
+      } catch (err) { cb(err) }
+    }
+
+    flaska.requestStart(createReq({
+      url: '/nope',
+      method: 'GET',
+    }), createRes())
+  })
+
+  t.test(`should handle unexpected errors in on404 correctly`, function(cb) {
+    const assertError = new Error('should be seen')
+    let checkCtx = null
+    
+    let flaska = new Flaska({}, faker)
+    flaska.on404(function(ctx) {
+      checkCtx = ctx
+      throw assertError
+    })
+    flaska.get('/test', function() { throw new Error('should not be called') })
+    flaska.compile()
+
+    flaska.requestEnd = function(err, ctx) {
+      if (err && err !== assertError) return cb(err)
+
+      try {
+        assert.ok(err)
+        assert.ok(ctx)
+        assert.strictEqual(ctx, checkCtx)
+        assert.strictEqual(err, assertError)
+        cb()
+      } catch (err) { cb(err) }
+    }
+
+    flaska.requestStart(createReq({
+      url: '/nope',
+      method: 'GET',
+    }), createRes())
+  })
+
+  t.test(`should handle unexpected errors in middleware correctly`, function(cb) {
+    const assertError = new Error('should be seen')
+    let checkCtx = null
+    
+    let flaska = new Flaska({}, faker)
+    let middles = [function(ctx) {
+      checkCtx = ctx
+      throw assertError
+    }]
+    flaska.get('/test', middles, function() { throw new Error('should not be called') })
+    flaska.compile()
+
+    flaska.requestEnd = function(err, ctx) {
+      if (err && err !== assertError) return cb(err)
+
+      try {
+        assert.ok(err)
+        assert.ok(ctx)
+        assert.strictEqual(ctx, checkCtx)
+        assert.strictEqual(err, assertError)
+        cb()
+      } catch (err) { cb(err) }
+    }
+
+    flaska.requestStart(createReq({
+      url: '/test',
+      method: 'GET',
+    }), createRes())
+  })
+
   t.test('should work with synchronous handler', function(cb) {
     const assertBody = { a: 1 }
     let handler = function(ctx) {
diff --git a/test/flaska.out.test.mjs b/test/flaska.out.test.mjs
index baeb8c7..6d9175e 100644
--- a/test/flaska.out.test.mjs
+++ b/test/flaska.out.test.mjs
@@ -39,6 +39,28 @@ t.describe('#requestEnd()', function() {
 
     flaska.requestEnd(assertError, ctx)
   })
+  
+  t.test('calls backup onerror correctly if error throws', function(cb) {
+    const assertErrorNotSeen = new Error('should not be seen')
+    const assertError = new Error('test')
+
+    let onFinish = function(body) {
+      try {
+        assert.strictEqual(ctx.status, 500)
+        assert.strictEqual(ctx.body.status, 500)
+        assert.strictEqual(ctx.body.message, 'Internal Server Error')
+        cb()
+      } catch (err) { cb(err) }
+    }
+    const ctx = createCtx({}, onFinish)
+
+    let flaska = new Flaska({}, fakerHttp, fakeStream)
+    flaska.onerror(function() {
+      throw assertError
+    })
+
+    flaska.requestEnd(assertErrorNotSeen, ctx)
+  })
 
   t.test('call res and end correctly when dealing with objects', function(cb) {
     const assertStatus = 202