diff --git a/README.md b/README.md
index 522a5a8..437116a 100644
--- a/README.md
+++ b/README.md
@@ -1,11 +1,33 @@
 # DeFinMa - API
 
-This is the API to access the database of the digital fingerprint of plastics project.
+This is the API to access the database of the digital fingerprint of plastics project. A deep insight into the project
+structure can be gained in the 
+[Bachelor Thesis](https://definma.apps.de1.bosch-iot-cloud.com/assets/docs/Veit-Lukas_Bachelor-Thesis.pdf).
 
 ## API documentation
 
-The API is documented using the Open API Specification 3.0.2 and hosted together with the API under the `/api` path
+The API is documented using the Open API Specification 3.0.2 in the [api](./api) and hosted together with the API under 
+the `/api-doc` path. The online version can be found [here](https://definma-api.apps.de1.bosch-iot-cloud.com/api-doc).
+The files are automatically bundled and validated when starting the server.
 
 ## Testing
 
 Testing is done with mocha and can be executed using `npm test`.
+
+## General structure
+
+[index.ts](./src/index.ts) is exectued when starting the server. It includes all setup tasks, registers middleware,
+routes and error handlers. Setting the `NODE_ENV` environment variable allows starting the server either in 
+`production`, `development` or `test` mode.
+
+All route files including the corresponding test files are in the [routes](./src/routes) folder. The 
+[validate](./src/routes/validate) folder stores Joi validations for data input and output.
+
+[models](./src/models) keeps all Mongoose database collection models.
+
+[helpers](./src/helpers) includes functions needed in multiple places like the authorization done for every route,
+csv conversion and object flattening as well as a mail service, registering an email address using the mail service on
+the BIC and replacing it with a logging statement in development.
+
+[test](./src/test) holds files for testing like the test database `db.json` loaded freshly for every test case and
+a helper utilized for easier testing. `loadDev` loads the `db.json` into the `development` database for a fresh start.
diff --git a/api/root.yaml b/api/root.yaml
index 019bfb6..749bd27 100644
--- a/api/root.yaml
+++ b/api/root.yaml
@@ -47,14 +47,9 @@
       500:
         $ref: 'api.yaml#/components/responses/500'
 
-/changelog/{timestamp}/{page}/{pagesize}:
+/changelog/{id}/{page}/{pagesize}:
   parameters:
-    - name: timestamp
-      in: path
-      required: true
-      schema:
-        type: string
-      example: 1970-01-01T00:00:00.000Z
+    - $ref: 'api.yaml#/components/parameters/Id'
     - name: page
       in: path
       required: true
@@ -69,9 +64,9 @@
       example: 30
   get:
     summary: get changelog
-    description: 'Auth: basic, levels: dev, admin<br>Displays all logs older than timestamp, sorted by date descending,
-    page defaults to 0, pagesize defaults to 25<br>Avoid using high page numbers for older logs, better use an older
-    timestamp'
+    description: 'Auth: basic, levels: dev, admin<br>Displays all logs older than timestamp of the given id, sorted by
+    date descending, page defaults to 0, pagesize defaults to 25
+    <br>Avoid using high page numbers for older logs, better use an older timestamp'
     tags:
       - /
     responses:
@@ -80,6 +75,8 @@
         content:
           application/json:
             schema:
+              allOf:
+                - $ref: 'api.yaml#/components/schemas/_Id'
               properties:
                 date:
                   type: string
diff --git a/src/routes/root.spec.ts b/src/routes/root.spec.ts
index a397423..c0a7c26 100644
--- a/src/routes/root.spec.ts
+++ b/src/routes/root.spec.ts
@@ -25,16 +25,18 @@ describe('/', () => {
     it('returns the first page', done => {
       TestHelper.request(server, done, {
         method: 'get',
-        url: '/changelog/1979-07-28T06:04:51.000Z/0/2',
+        url: '/changelog/120000030000000000000000/0/2',
         auth: {basic: 'admin'},
         httpStatus: 200
       }).end((err, res) => {
         if (err) return done(err);
+        console.log(res.body);
         should(res.body).have.lengthOf(2);
         should(res.body[0].date).be.eql('1979-07-28T06:04:51.000Z');
         should(res.body[1].date).be.eql('1979-07-28T06:04:50.000Z');
         should(res.body).matchEach(log => {
-          should(log).have.only.keys('date', 'action', 'collection', 'conditions', 'data');
+          should(log).have.only.keys('_id', 'date', 'action', 'collection', 'conditions', 'data');
+          should(log).have.property('_id').be.type('string');
           should(log).have.property('action', 'PUT /sample/400000000000000000000001');
           should(log).have.property('collection', 'samples');
           should(log).have.property('conditions', {_id: '400000000000000000000001'});
@@ -46,7 +48,7 @@ describe('/', () => {
     it('returns another page', done => {
       TestHelper.request(server, done, {
         method: 'get',
-        url: '/changelog/1979-07-28T06:04:51.000Z/1/2',
+        url: '/changelog/120000030000000000000000/1/2',
         auth: {basic: 'admin'},
         httpStatus: 200
       }).end((err, res) => {
@@ -54,7 +56,8 @@ describe('/', () => {
         should(res.body).have.lengthOf(1);
         should(res.body[0].date).be.eql('1979-07-28T06:04:49.000Z');
         should(res.body).matchEach(log => {
-          should(log).have.only.keys('date', 'action', 'collection', 'conditions', 'data');
+          should(log).have.only.keys('_id', 'date', 'action', 'collection', 'conditions', 'data');
+          should(log).have.property('_id').be.type('string');
           should(log).have.property('action', 'PUT /sample/400000000000000000000001');
           should(log).have.property('collection', 'samples');
           should(log).have.property('conditions', {_id: '400000000000000000000001'});
@@ -66,7 +69,7 @@ describe('/', () => {
     it('returns an empty array for a page with no results', done => {
       TestHelper.request(server, done, {
         method: 'get',
-        url: '/changelog/1979-07-28T06:04:51.000Z/10/2',
+        url: '/changelog/120000030000000000000000/10/2',
         auth: {basic: 'admin'},
         httpStatus: 200
       }).end((err, res) => {
@@ -75,28 +78,19 @@ describe('/', () => {
         done();
       });
     });
-    it('rejects timestamps pre unix epoch', done => {
+    it('rejects invalid ids', done => {
       TestHelper.request(server, done, {
         method: 'get',
-        url: '/changelog/1879-07-28T06:04:51.000Z/10/2',
+        url: '/changelog/12000003000000h000000000/10/2',
         auth: {basic: 'admin'},
         httpStatus: 400,
-        res: {status: 'Invalid body format', details: '"timestamp" must be greater than or equal to "1970-01-01T00:00:00.000Z"'}
-      });
-    });
-    it('rejects invalid timestamps', done => {
-      TestHelper.request(server, done, {
-        method: 'get',
-        url: '/changelog/1979-14-28T06:04:51.000Z/10/2',
-        auth: {basic: 'admin'},
-        httpStatus: 400,
-        res: {status: 'Invalid body format', details: '"timestamp" must be in ISO 8601 date format'}
+        res: {status: 'Invalid body format', details: 'Invalid object id'}
       });
     });
     it('rejects negative page numbers', done => {
       TestHelper.request(server, done, {
         method: 'get',
-        url: '/changelog/1979-07-28T06:04:51.000Z/-10/2',
+        url: '/changelog/120000030000000000000000/-10/2',
         auth: {basic: 'admin'},
         httpStatus: 400,
         res: {status: 'Invalid body format', details: '"page" must be greater than or equal to 0'}
@@ -105,7 +99,7 @@ describe('/', () => {
     it('rejects negative pagesizes', done => {
       TestHelper.request(server, done, {
         method: 'get',
-        url: '/changelog/1979-07-28T06:04:51.000Z/10/-2',
+        url: '/changelog/120000030000000000000000/10/-2',
         auth: {basic: 'admin'},
         httpStatus: 400,
         res: {status: 'Invalid body format', details: '"pagesize" must be greater than or equal to 0'}
@@ -114,7 +108,7 @@ describe('/', () => {
     it('rejects request from a write user', done => {
       TestHelper.request(server, done, {
         method: 'get',
-        url: '/changelog/1979-07-28T06:04:51.000Z/10/2',
+        url: '/changelog/120000030000000000000000/10/2',
         auth: {basic: 'janedoe'},
         httpStatus: 403
       });
@@ -122,7 +116,7 @@ describe('/', () => {
     it('rejects requests from an API key', done => {
       TestHelper.request(server, done, {
         method: 'get',
-        url: '/changelog/1979-07-28T06:04:51.000Z/10/2',
+        url: '/changelog/120000030000000000000000/10/2',
         auth: {key: 'admin'},
         httpStatus: 401
       });
@@ -130,7 +124,7 @@ describe('/', () => {
     it('rejects unauthorized requests', done => {
       TestHelper.request(server, done, {
         method: 'get',
-        url: '/changelog/1979-07-28T06:04:51.000Z/10/2',
+        url: '/changelog/120000030000000000000000/10/2',
         httpStatus: 401
       });
     });
diff --git a/src/routes/root.ts b/src/routes/root.ts
index cee54fe..165da7e 100644
--- a/src/routes/root.ts
+++ b/src/routes/root.ts
@@ -22,19 +22,18 @@ router.get('/authorized', (req, res) => {
   });
 });
 
-router.get('/changelog/:timestamp/:page?/:pagesize?', (req, res, next) => {
+router.get('/changelog/:id/:page?/:pagesize?', (req, res, next) => {
   if (!req.auth(res, ['dev', 'admin'], 'basic')) return;
 
   const {error, value: options} = RootValidate.changelogParams({
-    timestamp: req.params.timestamp,
+    id: req.params.id,
     page: req.params.page,
     pagesize: req.params.pagesize
   });
   if (error) return res400(error, res);
 
-  const id = new mongoose.Types
-    .ObjectId(Math.floor(new Date(options.timestamp).getTime() / 1000).toString(16) + '0000000000000000');
-  ChangelogModel.find({_id: {$lte: id}}).sort({_id: -1}).skip(options.page * options.pagesize).limit(options.pagesize)
+  ChangelogModel.find({_id: {$lte: mongoose.Types.ObjectId(options.id)}})
+    .sort({_id: -1}).skip(options.page * options.pagesize).limit(options.pagesize)
     .lean().exec((err, data) => {
     if (err) return next(err);
 
diff --git a/src/routes/validate/root.ts b/src/routes/validate/root.ts
index a932196..a6dfe33 100644
--- a/src/routes/validate/root.ts
+++ b/src/routes/validate/root.ts
@@ -28,7 +28,7 @@ export default class RootValidate {  // validate input for root methods
 
   static changelogParams (data) {
     return Joi.object({
-      timestamp: this.changelog.timestamp.required(),
+      id: IdValidate.get(),
       page: this.changelog.page,
       pagesize: this.changelog.pagesize
     }).validate(data);
@@ -39,6 +39,7 @@ export default class RootValidate {  // validate input for root methods
     data.collection = data.collection_name;
     data = IdValidate.stringify(data);
     const {value, error} = Joi.object({
+      _id: IdValidate.get(),
       date: this.changelog.timestamp,
       action: this.changelog.action,
       collection: this.changelog.collection,