> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cloud.coinbase.com/llms.txt
> Use this file to discover all available pages before exploring further.

# FIX

Financial Information eXchange (FIX) is the de‑facto protocol used by institutions for electronic trading. Coinbase Prime offers a FIX 4.2 gateway for order entry, status, and cancellations, so you can plug existing trading infrastructure straight into the crypto market.

<Note>
  Why choose FIX? Deterministic message sequencing, millisecond round‑trips, mature open‑source engines, and easy colocation with traditional‑finance systems.
  Why stick with REST? More intuitive initial implementation if unfamiliar with FIX Protocol.
</Note>

## How FIX fits into the Prime API stack

| Layer                           | What it does                         | Typical use                                           |
| ------------------------------- | ------------------------------------ | ----------------------------------------------------- |
| FIX                             | Order entry, cancel, drop‑copy       | Systematic trading, HFT, post‑trade reconciliation    |
| Websocket (`l2_data`, `orders`) | Streaming order book + order updates | UI embed, order oversight                             |
| REST                            | Trading, transfers, reporting        | Wallet creation, reconciliation, trading, withdrawals |

Most automated desks run two FIX sessions:

1. Order‑entry session – only returns Execution Reports for orders submitted on that session (DropCopyFlag `9406=N`).
2. Drop‑copy session – streams *all* portfolio fills regardless of source (DropCopyFlag `9406=Y`).

***

## Best‑practice playbook

### Order & fill management

* Persist to disk (or DB) so a restart doesn't lose state
* On startup, call REST Open Orders and reconcile with your cache

### Resiliency & recovery

1. Re‑establish FIX; historical Execution Reports will **automatically replay** from Coinbase for any messages missed while disconnected.
2. Use FIX message type `H` or the REST Get Order by ID endpoint to retrieve specific order info.
3. **Daily release window**: Between **5:00–5:05 PM ET**, sessions may forcibly disconnect.

* Avoid manual disconnects or resets 2–3 minutes before 5 PM. GTD orders may cancel at expiry, and you could miss final reports
* If disconnected during this window, reconnect **after 5:05 PM ET** and confirm all state via FIX `H` or REST
* **Note:** Execution Reports are retained during downtime and will be sent upon reconnection

## Funds Available for Trading

### Portfolio Margin enabled:

Use the `Buying Power` and other [Portfolio Margin APIs](/api-reference/prime-api/rest-api/financing/get-margin-information) to determine trading availability.

### Financing **not** enabled:

Use the REST [balances](/api-reference/prime-api/rest-api/balances/get-wallet-balance) endpoint with:

```http theme={null}
GET /balances?balance_type=TRADING_BALANCES
```

### Real-time Monitoring

Use any or all of the following for fill + order state monitoring:

* FIX Execution Reports (entry or drop-copy session)
* WebSocket orders channel (shows orders across all sources: FIX, REST, UI)

To scope FIX messages:

* `DropCopyFlag=9406=N` → Only orders created via current FIX session
* `DropCopyFlag=9406=Y` → All orders and fills across the portfolio

Multiple connections are suggested for redundancy. Your code should gracefully handle disconnects and reconnects.

## Go Sample App

To test FIX with a Prime API key, clone the [Prime FIX Go](https://github.com/coinbase-samples/prime-fix-go) sample app. For full setup details, review the README.

The Go client exposes one REPL command per flow (`new`, `status`, `cancel`). Execution Reports are flushed to `orders.json` for later reference.

## See also

* [Reference Go client](https://github.com/coinbase-samples/prime-fix-go)
* [Prime FIX Connectivity](/prime/fix-api/connectivity)
* [Prime FIX Order Entry Messages](/prime/fix-api/order-entry-messages)
* [Prime FIX Administrative Messages](/prime/fix-api/admin-messages)
* [FIX 4.2 spec](https://www.fixtrading.org/standards/)