Fractal Credentials API

Authorize transactions by including a Fractal proof in their payload.

Credentials API enable you to verify the credentials associated with a wallet address in your smart contract (on-chain) or in your dApp. With Credentials API, your dApp makes a call to the API with a wallet address.

The API replies with a credential proof if it exists associated with that wallet address. Your dApp includes the proof with the transaction sent to your smart contract which can verify the credential by importing our CredentialVerifier.sol contract to inherit its requiresCredential modifier. To get more details and examples check our verifiers documentation.

Using the Credentials API, you can leverage our existing user base with a quick and easy solution to access the provably verifiable KYC/KYB status of the identity behind a wallet address and validate it on-chain.

For compliance purposes, you may be required to access the user data supporting the issued Credential. In order to do this, make sure to follow the directions in obtaining user's data in the Message format section.

You can play around with a demo on https://credentials-api.demo.fractal.id/. Its full source code is available at https://github.com/trustfractal/credentials-api-demo.

Environments

Environment	URL	Signing address
Staging	credentials.next.fractal.id	0x2fCAb633adFA6aF8266025D63228047033c3ceD0
Production	credentials.fractal.id	0xacD08d6714ADba531beFF582e6FD5DA1AFD6bc65

Before using

You are required to create an application using our Developer Dashboard in order to use this API. See how here.

Usage

1. Before a user interacts with your contract, ask them to sign a message authorizing Fractal to respond on their behalf.

2. Send this message and signature to Fractal's API, which returns an expiry timestamp (24 hours in the future), a proof (Fractal's signature of the user's credential) and other relevant fields.

3. Use this these fields and the proof as arguments to your contract's method.

// using web3.js and MetaMask

const message = `I authorize Defistarter (dc3aa1910acbb7ff4d22c07e43a6926adc3a81305a9355a304410048c9a91afd) to get a proof from Fractal that:
- I passed KYC level plus+liveness
- I am not a citizen of the following countries: Germany (DE)
- I am not a resident of the following countries: Germany (DE)`;

const account = (await web3.eth.getAccounts())[0];
const signature = await ethereum.request({
    method: "personal_sign", 
    params: [message, account]
});

const { 
    address,
    approvedAt,
    fractalId,
    proof,
    validUntil
} = await FractalAPI.getProof(message, signature);

const mainContract = new web3.eth.Contract(contractABI, contractAddress);
mainContract.methods.main(proof, validUntil, approvedAt, fractalId).send({ from: account });

Getting a KYC/KYB proof

Get proof

GET credentials.fractal.id

Query Parameters

Name	Type	Description
message*	String	Message that authorizes sharing KYC/KYB data and defines credential requirements
signature*	String	Signature of message using personal_sign

200: OK

{
    "approvedAt": 1654693829,
    "address": "0xC61bA26E1C0F463Cd1BB57C962c6e7E411E79cb4",
    "fractalId": "0x02f1da55bc94926ef44faa6153cc9ad4f1e0f5ec3844b7c12ef96dea88657fdd",
    "validUntil": 1656080869,
    "proof": "0x8951496d1d0091945647fb425310e66ea766254bf52899bdca6d8fd70cda2e26091ba3fefad64428b07d78caf1f1ed077b6ca1ee1e6682c6838ad73a3d95ace51c",
    "credential": "level:plus+liveness;citizenship_not:de;residency_not:de"
}

400: Bad Request

{
    "error": <error_code>
}

404: Not Found No user with this wallet meets the KYC requirements

{
    "address": "0x123",
    "error": "user_not_found"
}

404: Not Found A pending user with this wallet meets the KYC requirements

{
    "address": "0x123",
    "error": "user_pending"
}

JavaScript example

// using web3.js and MetaMask

async function main() {
  const message = `I authorize Defistarter (dc3aa1910acbb7ff4d22c07e43a6926adc3a81305a9355a304410048c9a91afd) to get a proof from Fractal that:
- I passed KYC level plus+liveness
- I am not a citizen of the following countries: Germany (DE)
- I am not a resident of the following countries: Canada (CA), Germany (DE), United States of America (US)`;

  const account = (await web3.eth.getAccounts())[0];
  const signature = await ethereum.request({
    method: "personal_sign", 
    params: [message, account]
  });

  const encMessage = encodeURIComponent(message);

  try {
    const res = await fetch(`https://credentials.fractal.id?message=${encMessage}&signature=${signature}`);
    const proof = await res.json();
    // do something with proof
    console.log(proof);
  } catch (err) {
    console.log(err);
  }
}

Message format

You can easily generate a valid message using the example code.

I authorize <application_name> (<client_id>) to get a proof from Fractal that:
- I passed <verification_type> level <level>
[- I am not a citizen of the following countries: <citizenship_country_list>]
[- I am not a resident of the following countries: <residency_country_list>]
[I also allow access to my data that was used to pass this level.]

Parameter
<application_name>	Name of your Fractal ID application
<verification_type>	KYB or KYC
<client_id>	UID of your Fractal ID application
<level>	Requested KYC/KYB level
<citizenship_country_list>	Citizenship country blocklist
<residency_country_list>	Residency country blocklist

Application name and UID

These can be found in the Developer Dashboard.

Verification type

Choose or verification type — KYB or KYC.

Level

Choose your required KYC/KYB level and addons. Please reach out to [e-mail] if you don't know what to choose.

You must choose 1 level and any number of addons in the following format:

<level>[+<addon>]* (e.g., basic+liveness+sow)

Country blocklists

You can define which countries should not be accepted for citizenship and/or residency. If a user matches your other requirements but is a citizen of or resides in one of the define countries, a credential will not be issued — it will result in a 404 response.

The format for each country list is the following:

<country_name> (<country_code>)[, <country_name> (<country_code>)]*
e.g., Germany (DE), United States of America (US)

The country code and name is checked against the ISO 3166-1 alpha-2 list.

Both lists are optional. In case you don't want to restrict any citizenship/residency country, the full line should be removed. An empty list of countries is not accepted.

uniqueness level does not support any country restrictions;

basic level supports only citizenship country restrictions;

plus level supports both citizenship and residency country restrictions.

Note that, currently, country blocklists only apply to individuals. In case of KYB, these are applied to the individual person representing the company.

Obtaining user's data

For compliance purposes, you might want to be able to access the user data supporting the issued Credential. In order to do this, you should include the last string described in the Message format.

I also allow access to my data that was used to pass this level.

By including this string, you'll have access to the user's data in the Developer dashboard.

Message examples

Example #1 — citizenship and residency restrictions, and access to user data

I authorize Defistarter (dc3aa1910acbb7ff4d22c07e43a6926adc3a81305a9355a304410048c9a91afd) to get a proof from Fractal that:
- I passed KYC level plus+liveness
- I am not a citizen of the following countries: Germany (DE)
- I am not a resident of the following countries: Canada (CA), Germany (DE), United States of America (US)
I also allow access to my data that was used to pass this level.

Example #2 — citizenship and residency restrictions (no access to user data)

I authorize Defistarter (dc3aa1910acbb7ff4d22c07e43a6926adc3a81305a9355a304410048c9a91afd) to get a proof from Fractal that:
- I passed KYC level plus+liveness
- I am not a citizen of the following countries: Germany (DE)
- I am not a resident of the following countries: Canada (CA), Germany (DE), United States of America (US)

Example #3 — citizenship restriction (no access to user data)

I authorize Defistarter (dc3aa1910acbb7ff4d22c07e43a6926adc3a81305a9355a304410048c9a91afd) to get a proof from Fractal that:
- I passed KYC level basic
- I am not a citizen of the following countries: Germany (DE)

Example #4 — no country restrictions (no access to user data)

I authorize Defistarter (dc3aa1910acbb7ff4d22c07e43a6926adc3a81305a9355a304410048c9a91afd) to get a proof from Fractal that:
- I passed KYC level plus+liveness

Message generator example

You can easily generate a message by using this example code snippet and inputting your own values.

Response format

Example response

{
    "approvedAt": 1654693829,
    "address": "0xC61bA26E1C0F463Cd1BB57C962c6e7E411E79cb4",
    "fractalId": "0x02f1da55bc94926ef44faa6153cc9ad4f1e0f5ec3844b7c12ef96dea88657fdd",
    "validUntil": 1656080869,
    "proof": "0x8951496d1d0091945647fb425310e66ea766254bf52899bdca6d8fd70cda2e26091ba3fefad64428b07d78caf1f1ed077b6ca1ee1e6682c6838ad73a3d95ace51c",
    "credential": "level:plus+liveness;citizenship_not:de;residency_not:de"
}

Field	Type	Description
approvedAt	UNIX timestamp	User approval timestamp
address	EVM address	User address
fractalId	Hex string	User unique identifier
validUntil	UNIX timestamp	Credential expiry timestamp (24h after issuance)
proof	Hex string	Signed proof of KYC/KYB
credential	String	The expectedCredential this proof is for

Error codes

400 Bad request

error: invalid_configuration Why? You've tried to add country restrictions that are not supported by the level you chose. Fix: Use only valid country restrictions — see Country blocklists.

error: invalid_client_id Why? The application_uid you have supplied is not in the system. Fix: Check if there's a typo; or create an application if you have not done so.

error: invalid_country Why? The country list(s) you supplied contain invalid country names or codes. Fix: Please refer to the ISO 3166-1 alpha-2 list or use our example message generator.

error: invalid_level Why? The level you supplied is not valid. Fix: Please refer to the KYC levels page.

error: invalid_message_schema Why? The message you supplied is not valid. Fix: Please use our example message generator or make sure that the message that you created matches the format described above.

error: invalid_params Why? The message and/or signature query parameter is missing. Fix: Both parameters are required.

error: invalid_signature Why? The signature you supplied is invalid. Fix: Please make sure to use personal_sign when requesting the user to sign the message.

404 Not Found

error: user_pending Why? There is a user in our system that matches your KYC/KYB requirements and is identified by the wallet address that signed the message. However, their verification has not yet been approved. Fix: Direct the user to Fractal ID — if they're waiting on Fractal to approve their verification, there's no further action; if they've been contacted by Fractal's Identity Specialists to update their data, they should do so in Fractal ID.

error: user_not_found Why? There is no user in our system that matches your KYC/KYB requirements and is identified by the wallet address that signed the message. Fix: Use your authorization link to direct the user to our KYC/KYB journey.

If you supply a valid signature parameterbut the message does not match, the flow of personal_recover may yield a random address. We include the recovered address in the response, so that you can check if it matches with the one that signed the message.

If it does not match, then there's a difference between the message you asked the user to sign and the one you sent to our endpoint.

Using the KYC/KYB proof

Please refer to this repo for an example on how to use the KYC/KYB proof in your smart contract.