"Missing Authentication Token" Error when calling DVLA MOT history API with Postman - rest

Question

Note - I am very much new to all this. Apologies if anything is unclear.
My overriding aim is to pull out MOT history data for a large batch of vehicles from the DVLA API. I understand that this can be done using Postman, which I am using (on a 64-bit Windows laptop if at all relevant).
The DVLA provide the following instructions
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Getting started
All API interfaces are implemented as restful APIs and accessed over https.
To access API you will need an API key that uniquely identifies the source of the request. DVSA will give you an API key if it approves your application.
You should keep your API key secure, as DVSA manages throttling and quotas at an API key level.
Each request must have the following mandatory fields in the header:
Accept: application/json+v6
x-api-key:
Content-type field confirms that the response type is in JSON format, and the x-api-key field serves your API key to identify the source of the request.
Technical resources
Access the API at https://beta.check-mot.service.gov.uk/
This root URL will change when the service moves from beta to live.
These 4 endpoints equate to the 4 methods of using the API:
/trade/vehicles/mot-tests?registration={registration}
‘Registration’ is the vehicle registration number.
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In order to test that this is possible, I am entering the following single request into the bar in Postman, selecting "POST" and hitting "SEND"
https://beta.check-mot.service.gov.uk/trade/vehicles/mot-tests?Content-type=application/json&x-api-key=ABCDEFGH&registration=MYREG
n.b. no inverted commas or other punctuation surrounds the actual values for ABCDEFH or MYREG
Expected result: Some sort of JSON with MOT history for this vehicle
Actual result: {"message": "Missing Authentication Token"}{"message": "Missing Authentication Token"}
I am unclear on:
- whether I should be using POST
what the +v6 after the application is necessary (other documentation leaves it out)
Why "Accept" and "Content-type" appear to be used interchangeably in the documentation
Whether the ordering of the parameters matters
Whether this can be equally tested by simply pasting the url into a browser
Thanks for any help

Answer 1

Reading through the Documentation found here:
https://dvsa.github.io/mot-history-api-documentation/
It mentions that those fields should be added as Headers:
Each request must have the following mandatory fields in
the header:
- Accept: application/json+v6
- x-api-key: <your api key>
There are example cURL requests on the site to help you with creating the request.
If you use Postman's Import feature within the app (found in the top right), you can add this cURL request in the Paste Raw Text tab.
curl -H "Accept: application/json+v6" -H "x-api-key: <your_api_key>" https://beta.check-mot.service.gov.uk/trade/vehicles/mot-tests\?registration=ZZ99ABC
This will give you an example request of what it should look like. From here, you will be able to add in your own API Token and send the request.

Answer 2

If you are using Postman, you can use the Authorization tab right under the request to give the required mandatory header fields. Select Header from Add to drop down. You can also add additional headers information using the next tab named Headers. (for example, the accept-headers).
Edit:
Authorization:
Headers Tab
Normally, you should be getting the authorization token when you register to the site in question(x-api-key here).You need to figure out the value of that token from the initial call's response headers. According to the document which Danny shared, you will be getting x-api-key from them once they approve your request.
Edit:
Alternatively, you can use import feature as Danny suggested in his answer. At the end of the day, you need to add the values as headers instead of query parameters.

Answer 3

For anyone using Python with the MOT history api and getting the same error message, try GET:
import requests
url = f'https://beta.check-mot.service.gov.uk/trade/vehicles/mot-tests?registration={plate_number}'
payload = {}
headers = {
'Accept': 'application/json+v6',
'x-api-key': 'your-api-key'}
response = requests.get(url, headers=headers, data=payload)
data = response.json()
model = data[0]['model'] # get the vehicle model for example
print(model)