diff --git a/doc/api/resources/checkinlists.rst b/doc/api/resources/checkinlists.rst
index af55db676..0c044b639 100644
--- a/doc/api/resources/checkinlists.rst
+++ b/doc/api/resources/checkinlists.rst
@@ -330,6 +330,8 @@ Order position endpoints
    ``order__status__in``, ``subevent__in``, ``addon_to__in``, and ``search``. The search for attendee names and order
    codes is now case-insensitive.
 
+   The ``.../redeem/`` endpoint has been added.
+
 .. http:get:: /api/v1/organizers/(organizer)/events/(event)/checkinlists/(list)/positions/
 
    Returns a list of all order positions within a given event. The result is the same as
@@ -427,7 +429,7 @@ Order position endpoints
    :statuscode 403: The requested organizer/event does not exist **or** you have no permission to view this resource.
    :statuscode 404: The requested check-in list does not exist.
 
-.. http:get:: /api/v1/organizers/(organizer)/events/(event)/checkinlists/(list)/positions/(id)
+.. http:get:: /api/v1/organizers/(organizer)/events/(event)/checkinlists/(list)/positions/(id)/
 
    Returns information on one order position, identified by its internal ID.
    The result format is the same as the :ref:`order-position-resource`, with one important difference: the
@@ -437,7 +439,7 @@ Order position endpoints
 
    .. sourcecode:: http
 
-      GET /api/v1/organizers/bigevents/events/sampleconf/checkinlists/1/positions/ HTTP/1.1
+      GET /api/v1/organizers/bigevents/events/sampleconf/checkinlists/1/positions/23442/ HTTP/1.1
       Host: pretix.eu
       Accept: application/json, text/javascript
 
@@ -494,3 +496,127 @@ Order position endpoints
    :statuscode 401: Authentication failure
    :statuscode 403: The requested organizer/event does not exist **or** you have no permission to view this resource.
    :statuscode 404: The requested order position or check-in list does not exist.
+
+.. http:post:: /api/v1/organizers/(organizer)/events/(event)/checkinlists/(list)/positions/(id)/redeem/
+
+   Tries to redeem an order position, identified by its internal ID, i.e. checks the attendee in. This endpoint
+   accepts a number of optional requests in the body.
+
+   :<json boolean questions_supported: When this parameter is set to ``true``, handling of questions is supported. If
+                                       you do not implement question handling in your user interface, you **must**
+                                       set this to ``false``. In that case, questions will just be ignored. Defaults
+                                       to ``true``.
+   :<json datetime datetime: Specifies the datetime of the check-in. If not supplied, the current time will be used.
+   :<json boolean force: Specifies that the check-in should succeed regardless of previous check-ins or required
+                         questions that have not been filled. Defaults to ``false``.
+   :<json boolean ignore_unpaid: Specifies that the check-in should succeed even if the order is in pending state.
+                                 Defaults to ``false``.
+   :<json string nonce: You can set this parameter to a unique random value to identify this check-in. If you're sending
+                        this request twice with the same nonce, the second request will also succeed but will always
+                        create only one check-in object even when the previous request was successful as well. This
+                        allows for a certain level of idempotency and enables you to re-try after a connection failure.
+   :<json object answers: If questions are supported/required, you may/must supply a mapping of question IDs to their
+                          respective answers. The answers should always be strings. In case of (multiple-)choice-type
+                          answers, the string should contain the (comma-separated) IDs of the selected options.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      POST /api/v1/organizers/bigevents/events/sampleconf/checkinlists/1/positions/234/redeem/ HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+
+      {
+        "force": false,
+        "ignore_unpaid": false,
+        "nonce": "Pvrk50vUzQd0DhdpNRL4I4OcXsvg70uA",
+        "datetime": null,
+        "questions_supported": true,
+        "answers": {
+          "4": "XS"
+        }
+      }
+
+   **Example successful response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 201 Created
+      Vary: Accept
+      Content-Type: application/json
+
+      {
+        "status": "ok"
+      }
+
+   **Example response with required questions**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 400 Bad Request
+      Content-Type: text/json
+
+      {
+        "status": "incomplete"
+        "questions": [
+          {
+            "id": 1,
+            "question": {"en": "T-Shirt size"},
+            "type": "C",
+            "required": false,
+            "items": [1, 2],
+            "position": 1,
+            "identifier": "WY3TP9SL",
+            "ask_during_checkin": true,
+            "options": [
+              {
+                "id": 1,
+                "identifier": "LVETRWVU",
+                "position": 0,
+                "answer": {"en": "S"}
+              },
+              {
+                "id": 2,
+                "identifier": "DFEMJWMJ",
+                "position": 1,
+                "answer": {"en": "M"}
+              },
+              {
+                "id": 3,
+                "identifier": "W9AH7RDE",
+                "position": 2,
+                "answer": {"en": "L"}
+              }
+            ]
+          }
+        ]
+      }
+
+   **Example error response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 200 OK
+      Content-Type: text/json
+
+      {
+        "status": "error",
+        "reason": "unpaid",
+      }
+
+   Possible error reasons:
+
+   * ``unpaid`` - Ticket is not paid for or has been refunded
+   * ``already_redeemed`` - Ticket already has been redeemed
+   * ``product`` - Tickets with this product may not be scanned at this device
+
+   :param organizer: The ``slug`` field of the organizer to fetch
+   :param event: The ``slug`` field of the event to fetch
+   :param list: The ID of the check-in list to look for
+   :param id: The ``id`` field of the order position to fetch
+   :statuscode 201: no error
+   :statuscode 400: Invalid or incomplete request, see above
+   :statuscode 401: Authentication failure
+   :statuscode 403: The requested organizer/event does not exist **or** you have no permission to view this resource.
+   :statuscode 404: The requested order position or check-in list does not exist.
diff --git a/doc/plugins/pretixdroid.rst b/doc/plugins/pretixdroid.rst
index 715297269..0dab596df 100644
--- a/doc/plugins/pretixdroid.rst
+++ b/doc/plugins/pretixdroid.rst
@@ -4,10 +4,10 @@ pretixdroid HTTP API
 The pretixdroid plugin provides a HTTP API that the `pretixdroid Android app`_
 uses to communicate with the pretix server.
 
-.. warning:: This API is intended **only** to serve the pretixdroid Android app. There are no backwards compatibility
-             guarantees on this API. We will not add features that are not required for the Android App. There is a
-             general-purpose :ref:`rest-api` that not yet provides all features that this API provides, but will do
-             so in the future.
+.. warning:: This API is **DEPRECATED** and will probably go away soon. It is used **only** to serve the pretixdroid
+             Android app. There are no backwards compatibility guarantees on this API. We will not add features that
+             are not required for the  Android App. There is a general-purpose :ref:`rest-api` that provides all
+             features that you need to check in.
 
 .. versionchanged:: 1.12
 
diff --git a/doc/spelling_wordlist.txt b/doc/spelling_wordlist.txt
index a042dda9b..e0e6df03d 100644
--- a/doc/spelling_wordlist.txt
+++ b/doc/spelling_wordlist.txt
@@ -34,6 +34,7 @@ gettext
 gunicorn
 hardcoded
 hostname
+idempotency
 inofficial
 invalidations
 iterable
diff --git a/src/pretix/api/views/checkin.py b/src/pretix/api/views/checkin.py
index e017c82c1..9541fbc5a 100644
--- a/src/pretix/api/views/checkin.py
+++ b/src/pretix/api/views/checkin.py
@@ -1,18 +1,25 @@
+from django.core.exceptions import ValidationError
 from django.db.models import Count, F, Max, OuterRef, Prefetch, Subquery
 from django.db.models.functions import Coalesce
 from django.shortcuts import get_object_or_404
 from django.utils.functional import cached_property
+from django.utils.timezone import now
 from django_filters.rest_framework import DjangoFilterBackend, FilterSet
 from rest_framework import viewsets
 from rest_framework.decorators import detail_route
+from rest_framework.fields import DateTimeField
 from rest_framework.response import Response
 
 from pretix.api.serializers.checkin import CheckinListSerializer
+from pretix.api.serializers.item import QuestionSerializer
 from pretix.api.serializers.order import OrderPositionSerializer
 from pretix.api.views import RichOrderingFilter
 from pretix.api.views.order import OrderPositionFilter
 from pretix.base.models import Checkin, CheckinList, Order, OrderPosition
 from pretix.base.models.organizer import TeamAPIToken
+from pretix.base.services.checkin import (
+    CheckInError, RequiredQuestionsError, perform_checkin,
+)
 from pretix.helpers.database import FixedOrderBy
 
 
@@ -201,3 +208,53 @@ class CheckinListPositionViewSet(viewsets.ReadOnlyModelViewSet):
             qs = qs.filter(item__in=self.checkinlist.limit_products.values_list('id', flat=True))
 
         return qs
+
+    @detail_route(methods=['POST'])
+    def redeem(self, *args, **kwargs):
+        force = bool(self.request.data.get('force', False))
+        ignore_unpaid = bool(self.request.data.get('ignore_unpaid', False))
+        nonce = self.request.data.get('nonce')
+        op = self.get_object()
+
+        if 'datetime' in self.request.data:
+            dt = DateTimeField().to_internal_value(self.request.data.get('datetime'))
+        else:
+            dt = now()
+
+        given_answers = {}
+        if 'answers' in self.request.data:
+            aws = self.request.data.get('answers')
+            for q in op.item.questions.filter(ask_during_checkin=True):
+                if str(q.pk) in aws:
+                    try:
+                        given_answers[q] = q.clean_answer(aws[str(q.pk)])
+                    except ValidationError:
+                        pass
+
+        try:
+            perform_checkin(
+                op=op,
+                clist=self.checkinlist,
+                given_answers=given_answers,
+                force=force,
+                ignore_unpaid=ignore_unpaid,
+                nonce=nonce,
+                datetime=dt,
+                questions_supported=self.request.data.get('questions_supported', True)
+            )
+        except RequiredQuestionsError as e:
+            return Response({
+                'status': 'incomplete',
+                'questions': [
+                    QuestionSerializer(q).data for q in e.questions
+                ]
+            }, status=400)
+        except CheckInError as e:
+            return Response({
+                'status': 'error',
+                'reason': e.code
+            }, status=400)
+        else:
+            return Response({
+                'status': 'ok',
+            }, status=201)
diff --git a/src/tests/api/test_checkin.py b/src/tests/api/test_checkin.py
index 34400c301..73b052645 100644
--- a/src/tests/api/test_checkin.py
+++ b/src/tests/api/test_checkin.py
@@ -4,9 +4,12 @@ from decimal import Decimal
 from unittest import mock
 
 import pytest
+from django.utils.timezone import now
 from django_countries.fields import Country
+from i18nfield.strings import LazyI18nString
 from pytz import UTC
 
+from pretix.api.serializers.item import QuestionSerializer
 from pretix.base.models import (
     Checkin, CheckinList, InvoiceAddress, Order, OrderPosition,
 )
@@ -436,3 +439,219 @@ def test_status(token_client, organizer, event, clist_all, item, other_item, ord
             'variations': []
         }
     ]
+
+
+@pytest.mark.django_db
+def test_custom_datetime(token_client, organizer, clist, event, order):
+    dt = now() - datetime.timedelta(days=1)
+    dt = dt.replace(microsecond=0)
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {
+        'datetime': dt.isoformat()
+    }, format='json')
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+    assert Checkin.objects.last().datetime == dt
+
+
+@pytest.mark.django_db
+def test_only_once(token_client, organizer, clist, event, order):
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {}, format='json')
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {}, format='json')
+    assert resp.status_code == 400
+    assert resp.data['status'] == 'error'
+    assert resp.data['reason'] == 'already_redeemed'
+
+
+@pytest.mark.django_db
+def test_reupload_same_nonce(token_client, organizer, clist, event, order):
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {'nonce': 'foobar'}, format='json')
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {'nonce': 'foobar'}, format='json')
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+
+
+@pytest.mark.django_db
+def test_multiple_different_list(token_client, organizer, clist, clist_all, event, order):
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {'nonce': 'foobar'}, format='json')
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist_all.pk, order.positions.first().pk
+    ), {'nonce': 'baz'}, format='json')
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+
+
+@pytest.mark.django_db
+def test_forced_multiple(token_client, organizer, clist, event, order):
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {}, format='json')
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {'force': True}, format='json')
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+
+
+@pytest.mark.django_db
+def test_require_paid(token_client, organizer, clist, event, order):
+    order.status = Order.STATUS_PENDING
+    order.save()
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {}, format='json')
+    assert resp.status_code == 404
+
+    clist.include_pending = True
+    clist.save()
+
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {}, format='json')
+    assert resp.status_code == 400
+    assert resp.data['status'] == 'error'
+    assert resp.data['reason'] == 'unpaid'
+
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {'ignore_unpaid': True}, format='json')
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+
+
+@pytest.fixture
+def question(event, item):
+    q = event.questions.create(question=LazyI18nString('Size'), type='C', required=True, ask_during_checkin=True)
+    a1 = q.options.create(answer=LazyI18nString("M"))
+    a2 = q.options.create(answer=LazyI18nString("L"))
+    q.items.add(item)
+    return q, a1, a2
+
+
+@pytest.mark.django_db
+def test_question_number(token_client, organizer, clist, event, order, question):
+    question[0].options.all().delete()
+    question[0].type = 'N'
+    question[0].save()
+
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {}, format='json')
+    assert resp.status_code == 400
+    assert resp.data['status'] == 'incomplete'
+    assert resp.data['questions'] == [QuestionSerializer(question[0]).data]
+
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {'answers': {question[0].pk: "3.24"}}, format='json')
+    print(resp.data)
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+    assert order.positions.first().answers.get(question=question[0]).answer == '3.24'
+
+
+@pytest.mark.django_db
+def test_question_choice(token_client, organizer, clist, event, order, question):
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {}, format='json')
+    assert resp.status_code == 400
+    assert resp.data['status'] == 'incomplete'
+    assert resp.data['questions'] == [QuestionSerializer(question[0]).data]
+
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {'answers': {question[0].pk: str(question[1].pk)}}, format='json')
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+    assert order.positions.first().answers.get(question=question[0]).answer == 'M'
+    assert list(order.positions.first().answers.get(question=question[0]).options.all()) == [question[1]]
+
+
+@pytest.mark.django_db
+def test_question_invalid(token_client, organizer, clist, event, order, question):
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {'answers': {question[0].pk: "A"}}, format='json')
+    assert resp.status_code == 400
+    assert resp.data['status'] == 'incomplete'
+    assert resp.data['questions'] == [QuestionSerializer(question[0]).data]
+
+
+@pytest.mark.django_db
+def test_question_required(token_client, organizer, clist, event, order, question):
+    question[0].required = True
+    question[0].save()
+
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {}, format='json')
+    assert resp.status_code == 400
+    assert resp.data['status'] == 'incomplete'
+    assert resp.data['questions'] == [QuestionSerializer(question[0]).data]
+
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {'answers': {question[0].pk: ""}}, format='json')
+    assert resp.status_code == 400
+    assert resp.data['status'] == 'incomplete'
+    assert resp.data['questions'] == [QuestionSerializer(question[0]).data]
+
+
+@pytest.mark.django_db
+def test_question_optional(token_client, organizer, clist, event, order, question):
+    question[0].required = False
+    question[0].save()
+
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {}, format='json')
+    assert resp.status_code == 400
+    assert resp.data['status'] == 'incomplete'
+    assert resp.data['questions'] == [QuestionSerializer(question[0]).data]
+
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {'answers': {question[0].pk: ""}}, format='json')
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+
+
+@pytest.mark.django_db
+def test_question_multiple_choice(token_client, organizer, clist, event, order, question):
+    question[0].type = 'M'
+    question[0].save()
+
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {}, format='json')
+    assert resp.status_code == 400
+    assert resp.data['status'] == 'incomplete'
+    assert resp.data['questions'] == [QuestionSerializer(question[0]).data]
+
+    resp = token_client.post('/api/v1/organizers/{}/events/{}/checkinlists/{}/positions/{}/redeem/'.format(
+        organizer.slug, event.slug, clist.pk, order.positions.first().pk
+    ), {'answers': {question[0].pk: "{},{}".format(question[1].pk, question[2].pk)}}, format='json')
+    assert resp.status_code == 201
+    assert resp.data['status'] == 'ok'
+    assert order.positions.first().answers.get(question=question[0]).answer == 'M, L'
+    assert set(order.positions.first().answers.get(question=question[0]).options.all()) == {question[1], question[2]}