NAV 2018 has a lot of predefined APIs. Lets look at them and get some data to your external app:

1. First of all, check your NAV instance OData services tab. It should has next marks:

If not - set them and restart the instance.

All standard APIs are pages in range 5470 - 5528 with page type = API. Please look at them to understand how they are organized. Use them as templates to create your own APIs.

2. Common beginning of all APIs is http://ServerName:Port/NAVInstance/api/beta/

For example: http://NAV2017:7048/DynamicsNAV110/api/beta/

(NAV2017 it's just a server name, not a NAV version :) )

3. For sending requests i use Postman client. It's free and very user-friendly.

NAV can work with next http methods:

GET - read records

POST - insert record

PATCH - modify record

DELETE - delete record

Also you can use different types of authorization:

basic login password

basic login webaccesstoken (generate web access token in your webservice user card in NAV and use it instead of password in basic authentication):

ntlm login password (choose NTLM authentication mark in your NAV instance) - I use this one

4. To obtain APIs full list use metadata:

GET http://NAV2017:7048/DynamicsNAV110/api/beta/$metadata

It's not exactly the list, but it's a description of all existing entities, their elements and bound actions.

5. Enter point for all APIs is companies entity:

GET http://nav2017:7048/DynamicsNAV110/api/beta/companies

Answer is (one company in database):

Let's choose it:

GET http://nav2017:7048/DynamicsNAV110/api/beta/companies(68a76662-a198-477b-8097-d9df2116514a)

Answer is:

Each entity table now contains ID field with number 8000 and data type = GUID. In next points i'll use its values in my requests.

6. Let's get our company information:

GET http://NAV2017:7048/DynamicsNAV110/api/beta/companies(68a76662-a198-477b-8097-d9df2116514a)/companyInformation

Answer is:

Pay attention that you also can obtain media through web service (CRONUS company picture from company information table)

7. Let's create new customer in database:

POST http://NAV2017:7048/DynamicsNAV110/api/beta/companies(68a76662-a198-477b-8097-d9df2116514a)/customers

For this action you have to add content-type header with application/json value:

Also we add request body:

The result will be (Status should be 201 Created):

Customer successfully appears in NAV:

8. Let's change our customer name.

We take id of created customer (297f3ece-6b12-4c76-b816-ed709e59522c), add request body with modification:

and add extra headers:

and use PATCH method:

PATCH http://NAV2017:7048/DynamicsNAV110/api/beta/companies(68a76662-a198-477b-8097-d9df2116514a)/customers(297f3ece-6b12-4c76-b816-ed709e59522c)

Name will change:

9. After that we can delete our customer with DELETE method:

DELETE http://NAV2017:7048/DynamicsNAV110/api/beta/companies(68a76662-a198-477b-8097-d9df2116514a)/customers(297f3ece-6b12-4c76-b816-ed709e59522c)

10. APIs allows you to use filters with $filter parameter:

GET http://nav2017:7048/DynamicsNAV110/api/beta/companies(68a76662-a198-477b-8097-d9df2116514a)/items?$filter=unitPrice%20gt%20100

This request returns you all items from database which has Unit Price greater then 100.

%20 used instead of spaces

gt - means greater then

Also you can use:

eq - equal

ne - not equal

lt - less then

And many others

11. APIs allows you to combine data from different tables with $expand parameter:

GET http://NAV2017:7048/DynamicsNAV110/api/beta/companies(68a76662-a198-477b-8097-d9df2116514a)/salesInvoices(f3674c2b-2750-48bf-bb98-01eb1415dd3e)?$expand=salesInvoiceLines

This request returns you Sales invoice with ID = f3674c2b-2750-48bf-bb98-01eb1415dd3e and all its lines.

12. For documents creating you could combine POST method with $expand parameter:

POST http://NAV2017:7048/DynamicsNAV110/api/beta/companies(68a76662-a198-477b-8097-d9df2116514a)/salesInvoices?$expand=salesInvoiceLines

Request Body:

This request will create for us New sales invoice for customer КЮЛ004 with 2 lines.

13. Bound action.

Yes, you could post your sales invoice with one simple request:

POST http://NAV2017:7048/DynamicsNAV110/api/beta/companies(68a76662-a198-477b-8097-d9df2116514a)/salesInvoices(df7424c7-0fff-4672-98ce-1f8a0805a2e7)/Microsoft.NAV.Post

(where df7424c7-0fff-4672-98ce-1f8a0805a2e7 - ID of your sales invoice)

Sales invoices supports other actions - you can find them in metadata or in Sales Invoice entity page(5475):

That's all for today, hope that it was useful for you!