Introduction

The Hypatos API is organized around REST. The majority of the endpoints provide CRUD functionality for resources. The API is also exposing Intent Resources which mimic user intents or actions.

The Hypatos API uses OAuth 2.0 Client Credential Grant to authenticate requests. Before making any requests to any endpoint a client must authenticate with the authorization server and requests an access token from the token endpoint.

Authorization header contains client_id:client_secret encoded as explained in RFC Client Password section.

If the authorization server authenticated the client successfully, an access token is issued. Here is an example successful response:

This token can be used to authenticate the requests to API endpoints by sending a Bearer token in the Authorization HTTP header. The following example demonstrates how to use the access token to retrieve a list of documents.

Versioning

Changes to this API are released regularly. We use Semantic Versioning 2.0.0 scheme for versioning so that the clients can identify any backward-incompatible changes easily. Briefly summarized one can say, if the MAJOR version of the new API version didn't change you can expect the new version to be backward-compatible.

Rate limits

In order to maximise the stability of our API, we institue rate limits for all of API endpoints. Clients who send too many requests over a given period of time will see error responses that show up as status code 429 Too Many Requests.

When you see error responses with status code 429, it means you exhausted your current quota and need to withhold from sending further requests until the quota is reset. We encourage you not to wait until you get a 429 error but to monitor your quota in each request. In each response you receive from the API, you will find HTTP headers providing the details about your current quota. Here is the list of the HTTP headers:

• x-ratelimit-limit: Indicates the quota associated to the client in the current time-window followed by the description of the quota policy.
• x-ratelimit-remaining: Indicates the number of remaining requests in the current time-window
• x-ratelimit-reset: Indicates the number of seconds until quota reset of the current time-window

Please note that IETF is currently in the process of publishing a standard for these headers. Please explore the draft for more details.

A basic technique to gracefully handle rate limits is watch for your quota permanently and increase the time between your request as the quota is decreasing. To recover from a 429 error you need a retry mechanism following an exponential backoff schedule.