https://api.fincalc.co.ukThe FinCalc API offers a comprehensive suite of endpoints to support users with their financial planning requirements. All endpoints comply with the JSON data format for both input and output. To update existing data, it is recommended to use the PUT method. Therefore, a GET request should first be made to retrieve the relevant information, and the necessary changes can then be made before using the PUT method to update the data. Please note that the GET request may include formatted values that are not relevant to the PUT request. However, these irrelevant values will be ignored during the PUT request process.
Rate Limits
FinCalc applies two levels of limits to API usage.
API Rate Limits
This is a hard ceiling, measured per IP address, designed to protect the performance and reliability of the platform for all customers: API requests are limited to 400 requests per minute.
If you exceed this limit, the API will respond with a 429 Too Many Requests status and the message "Too many attempts. Try again later." We recommend implementing exponential backoff and retrying after a short delay.
Normal Usage
Separately from the API Rate Limit above, our Fair Use Policy sets out what we consider reasonable, everyday use of the API: as a general guide, up to 100 API calls per User Licence per day. This is deliberately lower than the API Rate Limit; it reflects ordinary business use, not a ceiling to design your integration around.
The API Rate Limit exists to protect the platform from short-term spikes. Normal Usage is about sustained, day-to-day volume. You can be well within the Rate Limit and still be asked to discuss your usage if it consistently and materially exceeds Normal Usage. Please visit our trust centre at https://trust.fincalc.co.uk to see the full Fair Use Policy.
Changelog and Updates
You can view a full history of changes to the API by clicking API changelog in the top navigation.
From there, you can subscribe to updates by email or RSS feed, so you're notified whenever the API changes. We'd recommend subscribing if you maintain an integration with FinCalc, so you can stay ahead of any changes that might affect your implementation.
Getting Help
If you have any questions about the API or need help with your integration, please reach out to our service desk at support@fincalc.co.uk.
This is version 2.0.0 of this API documentation. Last update on Aug 6, 2026.