Mock sample for your project: Tradeworks API

The Plaid REST API. Please see https://plaid.com/docs/api for more details.

NOWPayments is a non-custodial cryptocurrency payment processing platform. Accept payments in a wide range of cryptos and get them instantly converted into a coin of your choice and sent to your wallet. Keeping it simple – no excess.
Sandbox
Before production usage, you can test our API using the Sandbox. Details can be found here
Authentication
To use the NOWPayments API you should do the following:
Sign up at nowpayments.io
Specify your outcome wallet
Generate an API key
Standard e-commerce flow for NOWPayments API:
API - Check API availability with the "GET API status" method. If required, check the list of available payment currencies with the "GET available currencies" method.
UI - Ask a customer to select item/items for purchase to determine the total sum;
UI - Ask a customer to select payment currency
API - Get the minimum payment amount for the selected currency pair (payment currency to your Outcome Wallet currency) with the "GET Minimum payment amount" method;
API - Get the estimate of the total amount in crypto with "GET Estimated price" and check that it is larger than the minimum payment amount from step 4;
API - Call the "POST Create payment" method to create a payment and get the deposit address (in our example, the generated BTC wallet address is returned from this method);
UI - Ask a customer to send the payment to the generated deposit address (in our example, user has to send BTC coins);
UI - A customer sends coins, NOWPayments processes and exchanges them (if required), and settles the payment to your Outcome Wallet (in our example, to your ETH address);
API - You can get the payment status either via our IPN callbacks or manually, using "GET Payment Status" and display it to a customer so that they know when their payment has been processed.
API - you call the list of payments made to your account via the "GET List of payments" method. Additionally, you can see all of this information in your Account on NOWPayments website.
Alternative flow
API - Check API availability with the "GET API status" method. If required, check the list of available payment currencies with the "GET available currencies" method.
UI - Ask a customer to select item/items for purchase to determine the total sum;
UI - Ask a customer to select payment currency
API - Get the minimum payment amount for the selected currency pair (payment currency to your Outcome Wallet currency) with the "GET Minimum payment amount" method;
API - Get the estimate of the total amount in crypto with "GET Estimated price" and check that it is larger than the minimum payment amount from step 4;
API - Call the "POST Create Invoice method to create an invoice. Set "success_url" - parameter so that the user will be redirected to your website after successful payment.
UI - display the invoice url or redirect the user to the generated link.
NOWPayments - the customer completes the payment and is redirected back to your website (only if "success_url" parameter is configured correctly!).
API - You can get the payment status either via our IPN callbacks or manually, using "GET Payment Status" and display it to a customer so that they know when their payment has been processed.
API - you call the list of payments made to your account via the "GET List of payments" method. Additionally, you can see all of this information in your Account on NOWPayments website.
API Documentation
Instant Payments Notifications
IPN (Instant payment notifications, or callbacks) are used to notify you when transaction status is changed.
To use them, you should complete the following steps:
Generate and save the IPN Secret key in Store Settings tab at the Dashboard.
Insert your URL address where you want to get callbacks in createpayment request. The parameter name is ipn\callback\_url. You will receive payment updates (statuses) to this URL address.
You will receive all the parameters at the URL address you specified in (2) by POST request.
The POST request will contain the x-nowpayments-sig parameter in the header.
The body of the request is similiar to a get payment status response body.
Example:
{"paymentid":5077125051,"paymentstatus":"waiting","payaddress":"0xd1cDE08A07cD25adEbEd35c3867a59228C09B606","priceamount":170,"pricecurrency":"usd","payamount":155.38559757,"actuallypaid":0,"paycurrency":"mana","orderid":"2","orderdescription":"Apple Macbook Pro 2019 x 1","purchaseid":"6084744717","createdat":"2021-04-12T14:22:54.942Z","updatedat":"2021-04-12T14:23:06.244Z","outcomeamount":1131.7812095,"outcome_currency":"trx"}
Sort all the parameters from the POST request in alphabetical order.
Convert them to string using
JSON.stringify (params, Object.keys(params).sort()) or the same function.
Sign a string with an IPN-secret key with HMAC and sha-512 key
Compare the signed string from the previous step with the x-nowpayments-sig , which is stored in the header of the callback request.
If these strings are similar it is a success.
Otherwise, contact us on [email protected] to solve the problem.
Example of creating a signed string at Node.JS
const hmac = crypto.createHmac('sha512', notificationsKey);
hmac.update(JSON.stringify(params, Object.keys(params).sort()));
const signature = hmac.digest('hex');
Example of comparing signed strings in PHP
function checkipnrequestisvalid()
{
$error_msg = "Unknown error";
$auth_ok = false;
$request_data = null;
if (isset($SERVER['HTTPXNOWPAYMENTSSIG']) && !empty($SERVER['HTTPXNOWPAYMENTSSIG'])) {
$recivedhmac = $SERVER['HTTPXNOWPAYMENTS_SIG'];
$requestjson = fileget_contents('php://input');
$requestdata = jsondecode($request_json, true);
ksort($request_data);
$sortedrequestjson = jsonencode($requestdata);
if ($requestjson !== false && !empty($requestjson)) {
$hmac = hashhmac("sha512", $sortedrequestjson, trim($this->ipnsecret));
if ($hmac == $recived_hmac) {
$auth_ok = true;
} else {
$error_msg = 'HMAC signature does not match';
}
} else {
$error_msg = 'Error reading POST data';
}
} else {
$error_msg = 'No HMAC signature sent.';
}
}
Recurrent payment notifications
If an error is detected, the payment is flagged and will receive additional recurrent notifications (number of recurrent notifications can be changed in your Store Settings-> Instant Payment Notifications).
If an error is received again during processing of the payment, recurrent notifications will be initiated again.
Example: "Timeout" is set to 1 minute and "Number of recurrent notifications" is set to 3.
Once an error is detected, you will receive 3 notifications at 1 minute intervals.
Several payments for one order
If you want to create several payments for one Order you should do the following:
Create a payment for the full order amount.
Save "purchaseid" which will be in "createpayment" response
Create next payment or payments with this "purchaseid" in "createpayment" request.
Only works for partially_paid payments
It may be useful if you want to give your customers opportunity to pay a full order with several payments, for example, one part in BTC and one part in ETH. Also, if your customer accidentally paid you only part of a full amount, you can automatically ask them to make another payment.
Packages
Please find our out-of-the box packages for easy integration below:
JavaScript package
More coming soon!
Payments

Chaingateway.io
REST API to build the bridge between Ethereum and the real world
Please check out our website for detailed information about this API.
To use our API, you need an API Key (Described as Authorization header in the examples below).
To get one, please create an account on our website.
For our internal documentation, please check out our Docs Site.
If you need help with integrating our API in your application, you can reach us via email or join our official Telegram group.

Authentication is required to access all methods of the API. Enter username and password.
Credentials are automatically set as you type.

Stock and Forex Data and Realtime Quotes

Currency Authority: Exchange Rate of 1453 country currencies and crypto currencies

Portfolio Optimizer is a Web API to optimize the composition of investment portfolios (collection of financial assets such as stocks, bonds, ETFs, crypto-currencies) using modern portfolio theory-like algorithms (mean-variance, etc.).
API General Information
Portfolio Optimizer is based on REST for easy integration, uses JSON for the exchange of data and uses the two most common HTTP verbs (GET, POST) to represent the actions.
Portfolio Optimizer is also as secured as a Web API could be:
256-bit HTTPS Encryption
No usage of cookies
No usage of personal data
API Headers
The following HTTP header(s) are required when calling Portfolio Optimizer endpoints:
Content-type: application/json
This header specifies that the data provided in input to the endpoint is in JSON format
The following HTTP header(s) are optional when calling Portfolio Optimizer endpoints:
X-API-Key:
This header enables authenticated users to provide their private API key in order to benefit from higher API limits
API Key
Portfolio Optimizer is free to use, but not free to run.
In order to obtain an API key and benefit from higher API limits, a small participation to Portfolio Optimizer running costs is required.
This participation takes the form of coffee(s), with one coffee = one month of usage.
Notes:
> * Please make sure not to expose your API key publicly!
API Limits
Portfolio Optimizer comes with fairly reasonable API limits.
For anonymous users:
The API requests are restricted to a subset of all the available endpoints and/or endpoints features
The API requests are limited to 1 request per second for all the anonymous users combined, with concurrent requests rejected
The API requests are limited to 1 second of execution time
The API requests are limited to 20 assets, 100 portfolios, 500 series data points and 5 factors
For authenticated users with an API key:
The API requests have access to all the available endpoints and endpoints features
The API requests are limited to 10000 requests per 24 hour per API key, with concurrent requests queued
The API requests are limited to 2.5 seconds of execution time
The API requests are limited to 100 assets, 500 portfolios, 2500 series data points and 25 factors
> Notes:
> * It is possible to further relax the API limits, or to disable the API limits alltogether; please contact the support for more details.
> * Information on the API rate limits are provided in response messages HTTP headers x-ratelimit-*:
> * x-ratelimit-limit-second, the limit on the number of API requests per second
> * x-ratelimit-remaining-second, the number of remaining API requests in the current second
> * x-ratelimit-limit-minute, the limit on the number of API requests per minute
> * ...
API Regions
Portfolio Optimizer servers are located in Western Europe.
> Notes:
> * It is possible to deploy Portfolio Optimizer in other geographical regions, for example to improve the API latency; please contact the support for more details.
API Response Codes
Standard HTTP response codes are used by Portfolio Optimizer to provide details on the status of API requests.
| HTTP Code | Description | Notes |
| --------- | ----------- | ----- |
| 200 | Request successfully processed | - |
| 400 | Request failed to be processed because of incorrect content | The response message body contains information on the incorrect content |
| 401 | Request failed to be processed because of invalid API key | - |
| 404 | Request failed to be processed because of non existing endpoint | The requested endpoint might exist, but needs to be accessed with another HTTP method (e.g., POST instead of GET) |
| 429 | Request failed to be processed because of API limits violated | The response message HTTP headers x-ratelimit-* contain information on the API limits |
| 500 | Request failed to be processed because of an internal error | Something went wrong on Portfolio Optimizer side, do not hesitate to report the issue |
| 502 | Request failed to be processed because of a temporary connectivity error | Something went wrong on Portfolio Optimizer side, please check the API status and do not hesitate to report the issue |
API Status
Portfolio Optimizer is monitored 24/7 by UptimeRobot.
Support
For any issue or question about Portfolio Optimizer, please do not hesitate to contact the support.

Ntropy Transaction API for transaction classification & management
Contact Support:
Name: API Support
Email: [email protected]

Summary
The Swiss NextGen API is based on the NextGenPSD2 Framework Version 1.3.4 of the Berlin Group which offers a modern, open, harmonised and interoperable set of
Application Programming Interfaces (APIs) as the safest and most efficient way to provide data securely.
The NextGen Framework reduces XS2A complexity and costs, addresses the problem of multiple competing standards
in Europe and, aligned with the goals of the Euro Retail Payments Board,
enables European banking customers to benefit from innovative products and services ('Banking as a Service')
by granting TPPs safe and secure (authenticated and authorised) access to their bank accounts and financial data.
The Swiss edtion refines the message formats specific to Switzerland and defines some matching examples.
The possible Approaches are:
Redirect SCA Approach
(Not recommended by obp.ch community) OAuth SCA Approach
(Not recommended by obp.ch community) Decoupled SCA Approach
(Not recommended by obp.ch community) Embedded SCA Approach without SCA method
(Not recommended by obp.ch community) Embedded SCA Approach with only one SCA method available
(Not recommended by obp.ch community) Embedded SCA Approach with Selection of a SCA method
Not every message defined in this API definition is necessary for all approaches.
Furthermore this API definition does not differ between methods which are mandatory, conditional, or optional
Therefore for a particular implementation of a compliant API it is only necessary to support
a certain subset of the methods defined in this API definition.
**Please have a look at the implementation guidelines if you are not sure
which message has to be used for the approach you are going to use.**
Some General Remarks Related to this version of the OpenAPI Specification:
This API definition is based on the Implementation Guidelines of the Berlin Group API.
It is not a replacement in any sense.
The main specification is (at the moment) always the Implementation Guidelines of the Berlin Group API.
This API definition contains the REST-API for requests from the PISP to the ASPSP.
This API definition contains the messages for all different approaches defined in the Implementation Guidelines.
According to the OpenAPI-Specification [https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.1.md]
"If in is "header" and the name field is "Accept", "Content-Type" or "Authorization", the parameter definition SHALL be ignored."
The element "Accept" will not be defined in this file at any place.
The elements "Content-Type" and "Authorization" are implicitly defined by the OpenApi tags "content" and "security".
There are several predefined types which might occur in payment initiation messages,
but are not used in the standard JSON messages in the Implementation Guidelines.
Therefore they are not used in the corresponding messages in this file either.
We added them for the convenience of the user.
If there is a payment product, which needs these fields, one can easily use the predefined types.
But the ASPSP need not to accept them in general.
**We omit the definition of all standard HTTP header elements (mandatory/optional/conditional)
except they are mentioned in the Implementation Guidelines.**
Therefore the implementer might add these in his own realisation of a comlient API in addition to the elements defined in this file.
General Remarks on Data Types
The Berlin Group definition of UTF-8 strings in context of the API have to support at least the following characters
a b c d e f g h i j k l m n o p q r s t u v w x y z
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
0 1 2 3 4 5 6 7 8 9
/ - ? : ( ) . , ' +
Space

Fetch the latest currency exchange rates via API. ExchangeRate-API is free and unlimited.

The Assets API exposes fixed asset related functions of the Xero Accounting application and can be used for a variety of purposes such as creating assets, retrieving asset valuations etc.

Swagger for Account and Transaction API Specification