Authentication

Getting authenticated as a developer

DIMO Check-in

1. Make sure you obtain a Developer License via the Console before authentication.

2. The Developer SDKs have functions related to authentication that can expedite the process. You can likely skip this step if you are using the SDKs.

Getting a JWT

Before you go through authentication with DIMO, there are 3 types of JWT as described below:

JWT Type	What is this?	Expiration	How to get it?
User JWT	A user JWT contains your Developer License as the audience with the logged in user's account in the ethereum_address field. This JWT validates that the user is authenticated with DIMO.	14 days, user will need to re-authenticate again.	Utilize Login with DIMO on the frontend.
Developer JWT	A developer JWT contains your Developer License as both the audience and the ethereum_address. This JWT validates you as the app registered with DIMO.	Defaults to 14 days, developers will re-authenticate again programmatically. It is highly recommended to decode the JWT to get the updated expiration timestamp than to hardcode to 14 days.	Utilize your Developer License on the backend.
Vehicle JWT	A secondary developer JWT to access vehicle private data. This JWT is specific to a vehicle (identified by token_id) and an array of permissions granted by the user to the developer. This JWT validates that your app has permissions to get vehicle data. This was previously called privilege_token.	10 minutes, developers will trigger another exchange programmatically.	Use the Developer JWT on the Token Exchange API.

When dealing with JWT, it is highly recommended to both handle the errors in a try-catch-retry pattern and to decode the JWT to get the runtime expiration timestamp.

Authentication Format

DIMO uses Bearer Authentication format.

How it works

Authentication for DIMO works in 3 steps:

1. Generate Challenge: Generates a challenge and a state for a specific address.

2. Sign Challenge: To sign in to obtain a JSON Web Token to the API, the signer signs a cryptographic message, proving that they are the owner of the associated public key. This process is known as signing in with a digital signature.

3. Submit Challenge: The public key is then used to verify the user's digital signature and grant or deny access to the resources with the permissions set.

DIMO's implementation of the web3 signature mechanism for a backend application can be completed with the 3 steps below:

Step 1: Generate Challenge

POST https://auth.dimo.zone/auth/web3/generate_challenge

Query Parameters

Name	Type	Description
client_id*	String	Configured client identifier, this is the 0x client identifier received when you issue a Developer License.
domain*	String	A valid redirect URI for the client, this is the domain that you set when you configure a Developer License.
scope*	String	Space-separated list of scopes, this needs to be openid email
response_type*	String	This needs to be code.
address*	String	A hex-encoded, 0x-prefixed, 20-byte Ethereum address (case insensitive). This is the contract address of your Developer License as you are assuming the role of signer of the license. The value is essentially the same as the client_id.

200: Success

{
  "state":"jot5csziknrzscg2wcbtgaofu",
  "challenge":"auth.dimo.zone wants you to sign in with your Ethereum account:\n<YOUR_ADDRESS>\n\n<host> is asking you sign in.\n\nURI: https://auth.dimo.zone\nVersion: 1\nChain ID: 1\nNonce: 4P8AfZTqj9QwDM8tKc2vfIqQogxpXK\nIssued At: 2024-01-08T15:31:15Z"
}

Step 2: Sign Challenge

You will need to format the challenge string from Step 1 to hex and prefix it with 0x, combine that with an apiKey obtained from the Developer Console, before signing the Ethereum transaction and obtaining a 65-byte signature.

To sign the challenge, you will need to use a library in your preferred programming language to sign Ethereum transactions and messages with local private keys. We have provided a few language examples as a starter:

---

NodeJS

const web3 = require('web3');

const msg = "<challenge>"
const apiKey = "<api_key>"
const formattedKey = '0x' + Buffer.from(apiKey, 'utf8');

console.log(web3.eth.accounts.sign(msg, formattedKey));

Python

import siwe
from siwe import SiweMessage

from eth_account import Account
from eth_account.messages import encode_defunct
from eth_utils.curried import to_bytes

msg = "<challenge>"
apiKey = "<api_key>"

# No need to hexify when using siwe-py as the purpose of it is to help with formatting & verifying
# This is the pure Python way: hex_msg = '0x' + msg.encode().hex()

try:
    # Format the message
    message: SiweMessage = SiweMessage(message=msg)

    sn = encode_defunct(to_bytes(text=msg))
    acct = Account.from_key(apiKey)
    # Actual signing of the message
    sm = acct.sign_message(sn)
    print(sm)

except ValueError as e:
    # Invalid message
    print("Authentication attempt rejected - invalid message.")
except siwe.ExpiredMessage:
    print("Authentication attempt rejected - expired message.")
except siwe.DomainMismatch:
    print("Authentication attempt rejected - domain mismatch.")
except siwe.NonceMismatch:
    print("Authentication attempt rejected - nonce mismatch.")
except siwe.MalformedSession as e:
    # e.missing_fields contains the missing information needed for validation
    print("Authentication attempt rejected - malformed session.")
except siwe.InvalidSignature:
    print("Authentication attempt rejected - invalid signature.")

NodeJS

{
  message: 'auth.dimo.zone wants you to sign in with your Ethereum account:\n' +
    '0xf9D26323Ab49179A6d57C26515B01De018553666\n' +
    '\n' +
    'app.dimo.zone is asking you sign in.\n' +
    '\n' +
    'URI: https://auth.dimo.zone\n' +
    'Version: 1\n' +
    'Chain ID: 1\n' +
    'Nonce: EXVgxuxMiNfdWzwIcQU4XZ79zzwX6L\n' +
    'Issued At: 2024-01-22T15:34:47Z',
  messageHash: '0x293013bcae66e507384b791b35bd3701284b613887fc11d3a6debcde394c66db',
  v: '0x1c',
  r: '0xccd996ee0f2d18944034f29e5a9565158202d8d66194adcbe0c13eba96feb18e',
  s: '0x1783254ec656186cd1461693969c10aff0014f4690ee2f83781dbf8c4c657ef3',
  signature: '0xcbd996ee0f2d18944034f29e5a9565158202d8d66194adcbe0c13eba96feb18e1783254ec656186cd1461693969c10aff0014f4690ee2f83781dbf8c4a657ef31c'
}

Python

SignedMessage(messageHash=HexBytes('0x629749f84ee0d301f8eb02f3ef897b0c0a4553d2fdxd1fa0ea5cbbb6ff8bdfd5'), r=48064598734910045938712268846365002327886250846331651560012768739017714013389, s=54468135635475555126928311975236101130284121664770021136367631881584318718503, v=27, signature=HexBytes('0x6a43994c94195bf873b1025ae5778768a6311fb846bc21f5aeffc71f058394cd786bdf4d27e43e9a2358a4a0018f1af0333cbbf6318d6dd2be929e5f3fc9a2271b'))

Step 3: Submit Challenge

POST https://auth.dimo.zone/auth/web3/submit_challenge

Use x-www-form-urlencoded for body parameters.

Request Body

Name	Type	Description
client_id*	String	Configured client identifier, this is the 0x client identifier received when you issue a Developer License.
state*	String	The state string returned from Step 1.
grant_type*	String	This needs to be authorization_code.
domain*	String	A valid redirect URI for the client, this is the domain that you set when you configure a Developer License.
signature*	String	The 0x-prefixed signature obtained from Step 2.

200: Success

{
    "access_token": "eyJhbGciOiJSUzI1NiIsImtpZCI6Ijc4ZjVkNDk3ZjVjZDM3MzljYjNhYmZhZDExZjRhZWQ2ZWQxNmNhMWYifQ.eyJpc3MiOiJodHRwczovL2F1dGguZGV2LmRpbW8uem9uZSIsInByb3ZpZGVyX2lkIjoid2ViMyIsInN1YiI6IkNpb3dlR1k1UkRJMk16SXpRV0kwT1RFM09VRTJaRFUzUXpJMk5URTFRakF4UkdVd01UZzFOVE0zT0RjU0JIZGxZak0iLCJhdWQiOiJ2ZWhpY2xlLWdlbml1cyIsImV4cCI6MTcwNTkzNTg5MCwiaWF0IjoxNzA0NzI2MjkwLCJhdF9oYXNoIjoiQnBVZXJtcmJMMUlNVkxNdXpELW93USIsImVtYWlsX3ZlcmlmaWVkIjpmYWxzZSwiZXRoZXJldW1fYWRkcmVzcyI6IjB4ZjlEMjYzMjNBYjQ5MTc5QTZkNTddMjY1MTVCMDFEZTAxODU1Mzc4NyJ9.BrZeLozHwFxQoyTnpe9TVjoFFyqh3xs2xi6KQrguQGyyWoqFr03SjDCbY_Les6IUI9JD_xWf9bu04w82LD0NqsnO7nqrYwrVwriYUmh1cZskZPUDrL5_kMaN0FxQa-ea9g4ruVEXLU_aM206q2Wp7qqyjd5AhuPAgqAL6mDGviGXr2lJYfxrs0eclO9-w4Z4XO0hRkLO_ODhCDrBeKcwPHEmhTNH6Vw0ReI_05FwIFzz_biIpS6rj45F0nSLrMcJx-2UD9upaMDzLwA_9QPoXzoA3hfdPNKGPU0KEgMJF9thFa2K0daqXqAMXUkxwOSSYWdn58Z8NJGFWN6bzyJqC3",
    "token_type": "bearer",
    "expires_in": 1209599,
    "id_token": "eyJhbGciOiJSUzI1NiIsImtpZCI6Ijc4ZjVkNDk3ZjVjZDM3MzljYjNhYmZhZDExZjRhZWQ2ZWQxNmNhMWYifQ.eyJpc3MiOiJodHRwczovL2F1dGguZGV2LmRpbW8uem9usSIsInByb3ZpZGVyX2lkIjoid2ViMyIsInN1YiI6IkNpb3dlR1k1UkRJMk16SXpRV0kwT1RFM09VRTJaRFUzUXpJMk5URTFRakF4UkdVd01UZzFOVE0zT0RjU0JIZGxZak0iLCJhdWQiOiJ2ZWhpY2xlLWdlbml1cyIsImV4cCI6MTcwNTkzNTg5MCwiaWF0IjoxdzA0NzI2MjkwLCJhdF9oYXNoIjoibGdyZGx5UXhWVWlMY0o1ZWxmTU1odyIsImNfaGFzaCI6IkZid2NTVUlJcnl0S2xVblZHWjE4Z3ciLCJlbWFpbF92ZXJpZmllZCI6ZmFsc2UsImV0aGVyZXVtX2FkZHJlc3MiOiIweGY5RDI2MzIzQWI0OTE3OUE2ZDU3QzI2ETE1QjAxRGUwMTg1NTM3ODcifQ.afO4QhbCfzWZpB_VQhTuJBONA8hYMc8Dw97kNdDBwbYWCIZ_PFzIRUPJe75k19Y0oKm8hNeadyzV36x4uvv4wagfjEPXcttqzoiRrnFjwX5tHZgNaRSznBf6W6PoNzkx7GyGWmeW_AtV3Y4g_fDhC2PKVZeWlw346Prchf_mLDuC5d6HSydu4LoSGHRVhMXlbbwoXGcc3Jui-wMxli8gYx1N__5DXiGvasZgmZefRq9DqPhd5Nlp0AV7bDSSLVJOUZJybbHT153les-_IzMlyqowxrAaJl9ENk5ME5ak4g_gHUpJzPQAf3oe61K-sYKNUYcguah73xfysmbWc_bFsg"
}

400: Bad Request

{
    "status": 400,
    "message": "Requested resource does not exist."
}

Developer Notes

1. If you made it this far, you should have an access_token that you can use to access some DIMO API endpoints. For protected API endpoints such as Telemetry API, a Vehicle JWT described in Token Exchange API is required.

2. To use the access_token you received, please follow the Bearer Authentication Scheme to format your HTTP request headers. A typical format would look like { "Authorization": "Bearer <access_token>"}