# Saxo API error: InvalidModelState

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This is the markdown version of https://openbrokerapi.com/errors/saxo/invalid-model-state, written from the same records as that page.

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The error, as text you can copy:

```
InvalidModelState
```

- Kind: API error code
- HTTP status: 400
- API: [Saxo OpenAPI](https://openbrokerapi.com/brokers/saxo)
- Status: verified. Source: [developer.saxo](https://www.developer.saxo/openapi/learn/openapi-request-response), checked 2026-10-09.

## What does InvalidModelState mean on the Saxo API?

One or more properties of the request are not valid. The response carries a ModelState object that names each field at fault with its error texts. Saxo's order placement page says simple syntax errors return this code.

## How do I fix InvalidModelState?

Read the ModelState in the response and correct the fields it names. Saxo's page says these are errors an application should prevent by sending well formed JSON and allowed values.

## More on the Saxo API

- [All Saxo API error codes](https://openbrokerapi.com/errors/saxo)
- [Saxo API quickstart](https://openbrokerapi.com/brokers/saxo/quickstart): From credentials to a first call on a demo account, step by step.
- [Saxo API error codes](https://openbrokerapi.com/errors/saxo): 143 decoded, each with what it means, and the fix where the source gives one.
- [Saxo API endpoints](https://openbrokerapi.com/brokers/saxo/endpoints): 68 documented, each with its method, path, parameters and source.
- [Saxo messages](https://openbrokerapi.com/brokers/saxo/messages): 5 documented, each with its fields and source.
- [Saxo API page](https://openbrokerapi.com/brokers/saxo): The full record: access, authentication, limits and the source for each.

## Licence and how to cite

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Cite as: Saxo API error: InvalidModelState. Broker API Hub, https://openbrokerapi.com/errors/saxo/invalid-model-state, newest check 2026-10-09.

Where you rely on a single figure, cite the source and the checked date printed beside it as well. Where this page and a broker's own documentation differ, the documentation wins.