Rating Plugin

This page describes instructions for using the new JavaScript-based rating engine for Socotra, which supersedes the Liquid-based rating system.


This topic does not apply to rating for Premium Reports. Those continue to use Liquid rating.

The plugin will rate all perils for a policy transaction at one time. This allows doing calculations that are common across perils one time, and also makes it easier to manage situations where there are interdependencies between perils, such as in “minimum total premium” scenarios.

The basic approach is that a set of peril characteristics objects each need to be rated. The identities of those characteristics are passed by locator in the policyExposurePerils property of the data object, and each can be correlated with actual objects that are found in the policy property, which contains a full PolicyResponse object.

Each ratable peril characteristic must be rated with a RatingPluginPriceResponse object in the return object.

Enabling the Plugin

To enable the rating plugin for a product, in that product’s policy.json file, add a getPerilRates property to the plugin enablement section. For example:

  "plugins": {
    "getPerilRates": {
      "path": "main/rater.js",
      "enabled": true

Rating Calculations

Rating is done on a “per-peril” basis, where each segment of each peril is priced independently. There are three options for how the pricing calculation is done:

  • Specify the premium rate and let Socotra compute the actual price by multiplying by the duration of the segment; or

  • Specify the actual premium for the segment and let Socotra infer the rate; or

  • Specify both the actual premium and the rate

See Premium Calculations for details about premium and commission values and their exact- analogues.

Data Object

The following data object is passed to the plugin for use by the plugin code:

operation string new_business | endorsement | renewal | reinstatement
policyExposurePerils [RatingPluginCharacteristics]
tenantTimeZone string

endorsementLocator string
newPaymentScheduleName string
quoteLocator string
reinstatementLocator string
renewalLocator string
policyCharacteristicsLocator string
exposureCharacteristicsLocator string
perilCharacteristicsLocator string

Return Object

The object returned from the plugin should take the following form:

pricedPerilCharacteristics map<string,RatingPluginPriceResponse>

exceptionMessage string

The pricedPerilCharacteristics property is a map of the peril characteristics locators that are being priced to the specific pricing information:

exactPremium string
exactTechnicalPremium string
yearlyPremium string
yearlyTechnicalPremium string
recipient string

exactAmount string
yearlyAmount string


The response from the plugin must conform to the following criteria:

  • The keys in the return object’s pricedPerilCharacteristics map must correspond 1:1 with each perilCharacteristicsLocator in the input’s policyExposurePerils.

  • No priced characteristics other than those specified in the request should be returned.

Script Example: Calculating by Rate

The following implementation of rater.js illustrates a simplified rating algorithm:

function getPerilRates(data)
  let policy = data.policy;

  // This is the return object that we'll decorate with rating calculations
  let ret = { pricedPerilCharacteristics: {} };

  // For each peril characteristics object, look at its peril to get a rating
  // factor and then multiply by vehicle value to get the premium.
  for (const pep of data.policyExposurePerils)
    let peril = getPerilFromPerilCharacteristicsLocator(policy, pep);
    let exposureCharacteristics = getExposureCharacteristicsFromExposureCharacteristicsLocator(policy, pep);
    let vehicleValue = parseFloat(exposureCharacteristics.fieldValues.vehicle_value[0]);

    let ratingFactor;

    switch (peril.name)
      case "bodily_injury": ratingFactor = 52.0; break;
      case "collision": ratingFactor = 45.5; break;
      case "comprehensive": ratingFactor = 32.5; break;
      default: ratingFactor = 12.0; break;

    let yearlyPremium = round2(vehicleValue * ratingFactor / 1000);
    ret.pricedPerilCharacteristics[pep.perilCharacteristicsLocator] = {
      yearlyPremium: yearlyPremium,
      yearlyTechnicalPremium: round2(yearlyPremium * 0.8),
            yearlyAmount: round2(yearlyPremium * 0.1),
            recipient: "broker_abc" // a code that specifies who gets the commission
  return ret;
function getPerilFromPerilCharacteristicsLocator(policy, pep)
  for (exp of policy.exposures)
    for (peril of exp.perils)
      if (peril.characteristics.some(c => c.locator == pep.perilCharacteristicsLocator))
        return peril;
  throw `Peril characteristics ${pep.perilCharacteristicsLocator} not found!`;
function getExposureCharacteristicsFromExposureCharacteristicsLocator(policy, pep)
  for (exp of policy.exposures)
    if (exp.characteristics.some(c => c.locator == pep.exposureCharacteristicsLocator))
      return exp.characteristics.find(c => c.locator == pep.exposureCharacteristicsLocator);
  throw `ExposureCharacteristics ${pep.exposureCharacteristicsLocator} not found!`;
function round2(amount)
  return Math.round(amount * 100.0) / 100.0;

exports.getPerilRates = getPerilRates;

Script Example: Calculating Exact Premium

Suppose you have existing rating logic that calculates a yearly premium, but you want to assess it using a 360 day per year algorithm. You could then do something like this:


This Zip file contains the required library and associated support files for this example.

const { DateCalc } = require('../lib/DateCalc.js');
const { PolicyContext } = require('../lib/PolicyContext.js');

function getPerilRates(data)
  const dateCalc = new DateCalc(data.tenantTimeZone,
  const context = preprocessContext(new PolicyContext(data.policy));
  const charsToRate = data.policyExposurePerils
                          .map(pep => context.getPerilCharacteristics(pep.perilCharacteristicsLocator));

  const prices = {};

  for (const ch of charsToRate)

    // Assume some calculations have set the variable annualPremium
    const annualPremium = 500;

    // Calculate the number of days being rated
    const days = dateCalc.dayCountWhole(ch.coverageStartTimestamp,

    prices[ch.locator] = { yearlyPremium: annualPremium,
                           exactPremium: annualPremium * days / 365 };
  return { pricedPerilCharacteristics: prices };
function preprocessContext(context)
  for (const perCh of context.allPerilCharacteristics())
    perCh.coverageStartTimestamp = parseInt(perCh.coverageStartTimestamp);
    perCh.coverageEndTimestamp = parseInt(perCh.coverageEndTimestamp);
  return context;

exports.getPerilRates = getPerilRates;