# Saxo Data message

Independent and unofficial. Not affiliated with or endorsed by any broker or platform named here. Educational only: nothing here is advice, and nothing here recommends a broker or a trade.

This is the markdown version of https://openbrokerapi.com/brokers/saxo/messages/data-message, written from the same records as that page.

Risk warning: CFDs and spread bets are complex instruments and come with a high risk of losing money rapidly due to leverage. You can lose money on these products, and each provider publishes its own loss figure under FCA rules. You should consider whether you understand how they work and whether you can afford to take the high risk of losing your money. Automated and API trading can amplify losses through bugs, connectivity failures and runaway orders.

The binary layout every streaming message arrives in: a message id, the reference id of the subscription it belongs to, a payload format and the payload. One WebSocket frame can hold several messages, and one message can be split across frames.

- Message: `Data message`
- Interface: Saxo OpenAPI streaming connection
- Group: Message layout
- Status: verified. Source: [developer.saxo](https://www.developer.saxo/openapi/learn/streaming), checked 2026-10-12.

This is a message of the Saxo OpenAPI streaming connection, not an HTTP endpoint. It has no method and no path: it travels over an open WebSocket connection. It is in no OpenAPI file on this site and the request builder does not list it.

Note: The page says each message states its own size, so a client reads messages one after another until the frame is used up. It also says payloads are updates and not whole objects: only the properties that changed are sent, and they are applied in order to the snapshot the subscription call returned. Message ids are not to be read as a sequence.

## The message

- Name: `Data message`
- Direction: Event, sent by the server
- Carried by: WebSocket. Saxo's page says the connection is a plain WebSocket carrying data in binary frames. Subscriptions are not made on it: each is created with an HTTP POST that names the same context id, and those calls are recorded on this site as endpoints.
- Simulation, as the page's example prints it: `https://sim-streaming.saxobank.com/sim/oapi/streaming/ws/connect`

## Fields

- `Message identifier` (type 8 bytes, at byte 0, required): A 64 bit unsigned integer, little endian, that identifies the message. It is the value sent as messageid when reconnecting. The page says not to read any meaning or order into it.
- `Reserved` (type 2 bytes, at byte 8, required): Reserved for later use. To be ignored.
- `Reference id size` (type 1 byte, at byte 10, required): The number of bytes in the reference id that follows.
- `Reference id` (type ASCII, at byte 11, required): The reference id of the subscription the message belongs to, or the name of a control message, which starts with an underscore.
- `Payload format` (type 1 byte, after the reference id, required): 0 where the payload is UTF-8 text holding JSON, 1 where it is a binary Protocol Buffers message. The format is chosen when a subscription is set up, and control messages are always JSON.
- `Payload size` (type 4 bytes, after the payload format, required): A 32 bit unsigned integer: the number of bytes in the payload.
- `Payload` (type as many bytes as the payload size says, required): The message itself, read according to the payload format.

## Limits that apply at Saxo OpenAPI

- Headline limit: 120/min per session, per service group
  - Scope: session
  - Status: verified. Source: [developer.saxo](https://www.developer.saxo/openapi/learn/rate-limiting), checked 2026-09-18.
  - Note: Per session per service group; 1 order per second per session.

## More on Saxo

- [All Saxo messages](https://openbrokerapi.com/brokers/saxo/messages): 5 documented here, grouped by what they do.
- [Saxo API quickstart](https://openbrokerapi.com/brokers/saxo/quickstart)
- [All Saxo error codes](https://openbrokerapi.com/errors/saxo)
- [Saxo API page](https://openbrokerapi.com/brokers/saxo): The full record: access, authentication, limits and the source for each.

## Licence and how to cite

The records behind this page are all rights reserved. This file is the page itself, at its own address, in another format. It is not part of the CC BY 4.0 downloads listed at https://openbrokerapi.com/data. Quote from it with a link to the page.

Cite as: Saxo Data message. Broker API Hub, https://openbrokerapi.com/brokers/saxo/messages/data-message, newest check 2026-10-12.

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.