API Properties

Our APIs are provided as a REST service. New resources are added without notice. Resources are deprecated 6 months before removal, and the technical contact registered in Ons API Dashboard is notified of the deprecation The rest of this page explains the general workings and behaviour of our APIs. The list of available APIs and their documentation can be found here.

Environments

We have three different environments, with their own URL.

environment	use	URL
DEVELOPMENT	Developing your connector using fictional data	`https://api-development.ons.io`
STAGING	Test your connector on a customer’s test environment	`https://api-staging.ons.io`
PRODUCTION	Run your connector on a customer’s production environment	`https://api.ons.io`

Path and contexts

All endpoints start with the base path /t/, except the /ping endpoint.

Example
The path for the /clients/{id} endpoint on development is: api-development.ons.io/t/clients/3.

HTTP Methods

Our APIs support the REST verbs as expected.

GET

Used to retrieve resources and related data. Query parameters are used to select a sub-set or apply some sort of filtering. Query parameters are almost always optional. Requests do not change server state. Common urls include:

Format	Use
`/resource`	request all entries
`/resource/42`	request a particular entry
`/resource/42/sub_resource`	request all entries related to an entry
`/resource/x-stream-connect/data`	request all entries in a streaming matter

POST

Used to create new resources or perform some kind of action. POST requests are also used when sensitive data is transferred (like a login). For a 200 return status the same resource is returned with some updated fields. Requests change server state.

Format	Use
`/resource`	create a new resource
`/resource/42/sub_resource`	create a new sub-resource for resource
`/resource/42/action`	perform action for resource

PUT

Used to update an existing resource. The behaviour for POST also applies to PUT.

Format	Use
`/resource/42`	update resource

DELETE

Removes a particular resource or removes a relation between resources.

Format	Use
`/resource/42`	delete resource

Headers

It is possible to add headers to HTTP requests to our API. There are three headers that are of interest.

Accept

This header is required and defines the returned format. Some APIs return octet-streams (bytes) and the /ping returns text/plain. If you request something that can’t be given, you’ll receive a 406 status code. You can enter multiple formats; in that case the first one indicates your preference. Weights should also be supported. Applications which don’t specify the content-type in their accept-header wil receive JSON.

Accept: application/json

From mid 2024 only JSON is supported and not XML, not even if this is explicitly requested.

Content-Type

Required for POST and PUT calls. This header indicates the format used in the http body. You can only have one. The charset is optional but recommended.

Content-Type: application/json

User-Agent

The User-Agent header is optional but it would help us to identify your requests when something goes wrong.

User-Agent: connector/1.1+http://your-domain.com

Where connector should be replaced with the name of your connector.

HTTP Response codes

Below you can find a table with http response codes you can expect.

Status	Text	Description
200	OK	GET: valid response with your requested data in the response body. POST/PUT: valid response with your given resource enriched with some extra data in the response body.
201	Created	POST: object created, response has no body. There’s a Location header with the path where you can find the resource.
202	Accepted	PUT: changes are accepted, no response body.
204	No Content	POST: used for actions which were successful. GET: resource requested had no content.
304	Not Modified	GET: requested resource has not changed since it was last requested.
400	Bad request	GET: the combination of query params is invalid. POST/PUT: the given content is incorrect. You’ll receive an ErrorResponse body indicating what was wrong.
401	Unauthorized	You have insufficient rights to access the resource.
402	Payment required	Reserved for future use.
403	Forbidden	Authentication unsuccessful.
404	Not found	The requested resource was not found.
406	Not acceptable	Wrong Accept header.
409	Conflict	POST: The given resource already exists or was changed by another call.
410	Gone	The requested resource is no longer available at the requested address.
423	Locked	GET: The given resource is not yet ready. This is the case for delayed jobs that take some time to process.
429	Too many requests	You are being rate limited.
495	Invalid certificate	The SSL certificate is invalid. It might have expired, or it has not been signed by the correct certificate authority.
500	Internal server error	Something blew up on our side. We most likely got an error report, but it doesn’t hurt to report it.
502	Bad gateway	invalid upstream, this happens during updates.
503	Service unavailable	A service is down, this happens during updates.
504	Gateway timeout	A timeout somewhere in our infrastructure. This could happen due to updates or when our network is congested. It can also happen when your network is congested or broken.

Rate limiting

Requests are being rate limited to prevent connectors from using inefficient APIs for their use-cases; using the correct APIs should not bring API usage close to the enforced limits.

Currently we limit requests per connector to the following:

4 requests in parallel per certificate
100 requests per second (currently not enforced)
10.000 seconds of request time per day (currently not enforced)

Note

The latest is measured as a sum for all requests being done. This can be 100.000 requests that take 100 milliseconds each or 1 request that takes 10.000 seconds.

Only the connection limit is currently enforced. In the future, we might enforce the other limits as well. However, we will first investigate whether or not connectors will be affected by this.

Versioning

Our APIs are not versioned. Rather, we rely on marking resources as deprecated 6 months prior to removal. Keep an eye on the deprecation article and be prepared to adjust your connector. New resources are added as they become available, without further notice.