# TEOS API references

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Check [versioning](https://teos-docs.coreledger.net/changelog/versioning "mention") concept and [start trying](https://teos-docs.coreledger.net/get-started) out TEOS API
{% endhint %}

## Common request parameters

Most of the TEOS API calls require the authentication header: Bearer token.

[OData query builder syntax](https://docs.oasis-open.org/odata/odata/v4.01/odata-v4.01-part1-protocol.html) can be used for most of the TEOS API requests, swagger documentation provides explicitly the info about the methods that are already odata-compatible, and which are not.

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Please note that TEOS API is case-sensitive. Pay attention to the upper/lower-case usage within request data
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Please note that starting from v0.5 the API object referencing using "resource/key" style is **deprecated**
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## Examples of TEOS API calls

Test scripts made for [postman](https://www.postman.com) can be found in [TEOS API Github Repository](https://github.com/CoreLedger-TEOS/API). Contact CoreLedger support if you don't have access to it.

## Asynchronous processing of OData Actions and writing verbs

All changes to the blockchain state take more time than the usual synchronous request timeouts allow. Therefore, according to [OData Standard Point 11.6](https://docs.oasis-open.org/odata/odata/v4.01/os/part1-protocol/odata-v4.01-os-part1-protocol.html#sec_AsynchronousRequests), all exposed actions and writing http verbs are executed asynchronously and return `Code 202 Accepted` with the transaction ID even when the client does not specify `respond-async` in the request.