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Introduction

Theallow_unsafe parameter in the requests to /route & /msgs_direct endpoints is designed to protect users from bad trade execution. This parameter indicates whether you want to allow the API to return and execute a route even when our routing engine forecasts low or unknown execution quality:
  • allow_unsafe=false (default): The API will throw an error instead of returning a route when the routing engine forecasts bad execution quality (i.e. > 10% price_impact or difference between USD value in and out) or when execution quality can’t be determined.
  • allow_unsafe=true: The API will return a route for a trade even when the routing engine forecasts bad execution quality (i.e. > 10% price_impact or difference between USD value in and out) or when execution quality can’t be determined. In these cases, the API appends a warning to the response in a warning field
Make sure you understand execution/quote quality measurements firstBefore reading this doc, you should read our documentation on quote quality: Understanding Quote Quality Metrics. This provides basic background information about the different ways the Skip Go API measures whether a route will likely give a user a bad execution price, namely the difference between the USD value of the input and the output & on-chain price impact.

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allow_unsafe=false Behavior

When allow_unsafe=false, the endpoint throws an error when execution quality is poor (as measured by price impact or estimated USD value lost) or when execution quality can’t be determined (i.e. neither of these measurements are available). In particular, if allow_unsafe=false, /route and /msgs_direct return errors when:
  • price_impact > .10(the swap will move the on-chain price by more than 10%)
  • (usd_amount_in-usd_amount_out)/usd_amount_in)>.10 (greater than 10% of the value of the input is lost)
  • Neither of the above metrics can be computed
Below, we provide examples of the responses in each these cases. The price impact is greater than 10% (BAD_PRICE_ERROR): 
  "code": 3,  
  "message": "swap execution price in route deviates too far from market price. expected price impact: 98.6915%",  
  "details": [  
    {  
      "@type": "type.googleapis.com/google.rpc.ErrorInfo",  
      "reason": "BAD_PRICE_ERROR",  
      "domain": "skip.build",  
      "metadata": {}  
    }  
  ]  
}
The user loses more than 10% of their USD value (BAD_PRICE_ERROR): 
  "code": 3,  
  "message": "difference in usd value of route input and output is too large. input usd value: 1000 output usd value: 600",  
  "details": [  
    {  
      "@type": "type.googleapis.com/google.rpc.ErrorInfo",  
      "reason": "BAD_PRICE_ERROR",  
      "domain": "skip.build",  
      "metadata": {}  
    }  
  ]  
}
The price_impact and the estimated USD value difference cannot be calculated (LOW_INFO_ERROR)
JSON
{  
  "code": 3,  
  "message": "unable to determine route safety",  
  "details": [  
    {  
      "@type": "type.googleapis.com/google.rpc.ErrorInfo",  
      "reason": "LOW_INFO_ERROR",  
      "domain": "skip.build",  
      "metadata": {}  
    }  
  ]  
}

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allow_unsafe=true Behavior

When allow_unsafe=true, the endpoints will still return routes even when the routing engine forecasts will have unknown or poor execution quality (measured by price_impact or estimated USD lost), but they will have a warning field appended to them. The warning field is populated exactly when the endpoints would return an error if allow_unsafe were false, namely:
  • price_impact > .10(the swap will move the on-chain price by more than 10%)
  • (usd_amount_in-usd_amount_out)/usd_amount_in)>.10 (greater than 10% of the value of the input is lost)
  • Neither of the above metrics can be computed
Below, we provide examples of the responses in each these cases. The price impact is greater than 10% (BAD_PRICE_WARNING):
JSON
"warning": {  
    "type": "BAD_PRICE_WARNING",  
    "message": "swap execution price in route deviates too far from market price. expected price impact: 98.6826%"  
}
More than 10% of the USD value of the input is lost in the swap (BAD_PRICE_WARNING):
{
    "type": "BAD_PRICE_WARNING",  
    "message": "difference in usd value of route input and output is too large. input usd value: 1000 output usd value: 600"  
}
The price_impact and the estimated USD value difference cannot be calculated (LOW_INFO_ERROR) 
"warning": {  
    "type": "LOW_INFO_WARNING",  
    "message": "unable to determine route safety"  
}

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Best Practices for Protecting Users

Above all else, we recommend setting allow_unsafe=false In addition, we recommend reading our documentation around safe API integrations to learn about UX/UI practices that can further help prevent users from performing trades they’ll immediately regret.
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