Errors

Overview

The Forerunner API uses conventional HTTP status codes to indicate the success or failure of requests. This guide helps you understand error responses and resolve common issues.

HTTP Status Codes

Success Codes

Code	Meaning	Description
200	OK	Request succeeded
201	Created	Resource created successfully
204	No Content	Request succeeded with no response body

Client Error Codes

Code	Meaning	Description
400	Bad Request	Invalid request syntax or parameters
401	Unauthorized	Missing or invalid API key
403	Forbidden	Request blocked by WAF or insufficient permissions
404	Not Found	Requested resource does not exist
409	Conflict	Resource already exists (duplicate `externalSystemId`)
422	Unprocessable Entity	Request syntax is valid but contains semantic errors
429	Too Many Requests	Rate limit exceeded

Server Error Codes

Code	Meaning	Description
500	Internal Server Error	Unexpected server error occurred
502	Bad Gateway	Temporary server issue, retry with backoff
503	Service Unavailable	Server is temporarily unavailable
504	Gateway Timeout	Request timed out, retry with backoff

Error Response Format

All error responses follow a consistent JSON structure with an errors array:

{
  "errors": [
    {
      "message": "Human-readable error description",
      "field": "fieldName or path.to.field"
    }
  ],
  "file": null
}

Error responses also include endpoint-specific fields (like file, sisd, property, properties) set to null or empty arrays.

Example Error Responses

{
  "errors": [
    {
      "field": "fileType",
      "message": "Could not find AccountDocumentType with name invalidType for account abc123. Must be one of elevation_certificate, flood_map"
    }
  ],
  "file": null
}

Common Errors

Authentication Errors (401 Unauthorized)

Invalid or missing API key

Cause: API key is malformed, missing, or invalidSolution:

Verify API key is correctly formatted
Ensure Bearer prefix is included in Authorization header
Check for extra whitespace in API key value
Add Authorization header to all requests
Contact your Customer Success Manager for a new API key if expired

// Correct format
headers: {
  'Authorization': 'Bearer YOUR_API_KEY'
}

# Example with cURL
curl https://app.withforerunner.com/api/v1/properties \
  -H "Authorization: Bearer YOUR_API_KEY"

Request Blocked by WAF (403 Forbidden)

Request blocked when using Postman, Insomnia, or other HTTP clients

Cause: Forerunner’s web application firewall (WAF) blocks requests with common HTTP client User-Agent headers to prevent automated web scraping. This returns a 403 Forbidden response even when your API key is valid.Solution:

Remove or clear the User-Agent header in your HTTP client before sending requests
In Postman: Go to Headers, find User-Agent, and either delete it or set it to an empty value
In Insomnia: Go to Headers and remove the User-Agent entry
cURL does not typically trigger this issue, but if it does, pass an empty User-Agent:

curl https://app.withforerunner.com/api/v1/properties \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "User-Agent:"

Validation Errors

Missing required fields

Cause: Required parameter not provided in requestError example:

{
  "errors": [
    {
      "field": "value",
      "message": "Required field 'value' is missing"
    }
  ]
}

Solution:

Check API documentation for required fields
Ensure all required fields are included in request body

// Missing required field
{
  "type": "damage"
  // Missing: value, date
}

// Correct
{
  "type": "damage",
  "value": 125000,
  "date": "03/15/2024"
}

Invalid date format

Cause: Date provided in incorrect formatError example:

{
  "errors": [
    {
      "field": "date",
      "message": "Date must be in MM/DD/YYYY format"
    }
  ]
}

Solution:

Use MM/DD/YYYY format for date fields
Ensure leading zeros for single-digit months/days

// Incorrect
{ "date": "2024-03-15" }

// Correct
{ "date": "03/15/2024" }

Invalid file type

Cause: Unsupported or incorrect file type specifiedError example:

{
  "errors": [
    {
      "field": "fileType",
      "message": "Could not find AccountDocumentType with name invalidType"
    }
  ]
}

Solution:

Use valid file types provided by your account configuration
Check for typos in fileType parameter
Common types include: elevation_certificate, permit, map, photo, letter

// Incorrect
{ "fileType": "elevation-certificate" }

// Correct
{ "fileType": "elevation_certificate" }

Invalid GeoJSON

Cause: Malformed GeoJSON coordinates or geometrySolution:

Ensure GeoJSON follows standard format
Verify longitude comes before latitude: [longitude, latitude]
Validate GeoJSON structure with type and coordinates

// Incorrect
{
  "coordinates": {
    "lat": 39.78,
    "lng": -89.65
  }
}

// Correct
{
  "type": "Point",
  "coordinates": [-89.65, 39.78]
}

Invalid UUID format

Cause: Resource ID is not a valid UUIDError example:

{
  "errors": [
    {
      "field": "id",
      "message": "Invalid UUID format for id parameter"
    }
  ]
}

Solution:

Ensure resource IDs are valid UUIDs
Verify you’re using the correct ID from previous API responses

Resource Errors

Resource not found

Cause: Requested resource does not existSolution:

Verify resource ID is correct
Ensure resource hasn’t been deleted
Check you’re querying the correct environment (staging vs production)

Property not found or cannot be matched

Cause: Could not match address or parcel to a propertyError example:

{
  "errors": [
    {
      "field": "address",
      "message": "Could not find property matching the provided address"
    }
  ]
}

Solution:

Verify address format and spelling
Ensure property exists in your organization’s database
Try using parcel ID or coordinates if address matching fails
Provide multiple identifiers for better matching

// Provide multiple identifiers for better matching
{
  "address": "123 Main St, Springfield, IL",
  "parcelId": "12-34-567-890",
  "coordinates": {
    "type": "Point",
    "coordinates": [-89.65, 39.78]
  }
}

Cannot modify geospatial information

Cause: Attempted to modify address, parcelId, or coordinates on existing recordSolution:

Geospatial information cannot be changed after record creation
Delete the record and create a new one with correct location
Or keep existing record and update only non-geospatial fields

Duplicate resource (409 Conflict)

Cause: Resource with the same external system ID already existsError example:

{
  "errors": [
    {
      "field": "externalSystemId",
      "message": "Document upload already exists with external system id 12345"
    }
  ]
}

Solution:

Use a unique external system ID for each resource
Update the existing resource instead of creating a new one
Or omit the externalSystemId if not needed

File Upload Errors

File too large

Cause: Uploaded file exceeds size limitSolution:

Compress or resize files before upload
Split large documents into smaller files
Contact support if you need higher limits

Unsupported file format or MIME type

Cause: File format is not supported for the specified document typeError example:

{
  "errors": [
    {
      "field": "mimeType",
      "message": "MIME type \"image/jpeg\" is not allowed for document type \"elevation_certificate\""
    }
  ]
}

Solution:

Convert to supported format (PDF for elevation certificates, etc.)
Check file extension matches actual file type
Verify MIME type is allowed for your document type

Multipart form data required

Cause: File upload not sent as multipart/form-dataSolution:

Set Content-Type header to multipart/form-data
Use proper file upload mechanism with FormData

const formData = new FormData();
formData.append('fileUpload', file);

fetch('https://app.withforerunner.com/api/v1/files', {
  method: 'POST',
  headers: {
    'Authorization': 'Bearer YOUR_API_KEY'
    // Do NOT set Content-Type, let browser set it with boundary
  },
  body: formData
});

Implementing Error Handling

Basic Error Handling

async function makeApiRequest(url, options) {
  try {
    const response = await fetch(url, {
      ...options,
      headers: {
        'Authorization': 'Bearer YOUR_API_KEY',
        'Content-Type': 'application/json',
        ...options.headers
      }
    });

    const data = await response.json();

    // Check for errors in response
    if (data.errors && data.errors.length > 0) {
      console.error('API Errors:', data.errors);

      // Format error messages
      const errorMessages = data.errors
        .map(err => `${err.field}: ${err.message}`)
        .join(', ');

      switch (response.status) {
        case 400:
          throw new Error(`Bad Request: ${errorMessages}`);
        case 401:
          throw new Error('Authentication failed. Check your API key.');
        case 404:
          throw new Error(`Resource not found: ${errorMessages}`);
        case 409:
          throw new Error(`Conflict: ${errorMessages}`);
        case 422:
          throw new Error(`Validation error: ${errorMessages}`);
        case 429:
          throw new Error('Rate limit exceeded. Retry after delay.');
        case 500:
          throw new Error('Server error. Please try again later.');
        default:
          throw new Error(`API error: ${errorMessages}`);
      }
    }

    return data;
  } catch (error) {
    console.error('Request failed:', error);
    throw error;
  }
}

Exponential Backoff for Retries

Implement exponential backoff for transient errors (500, 502, 503, 504):

async function makeRequestWithRetry(url, options, maxRetries = 3) {
  let lastError;

  for (let attempt = 0; attempt < maxRetries; attempt++) {
    try {
      const response = await fetch(url, options);
      const data = await response.json();

      // Don't retry client errors (4xx)
      if (response.status >= 400 && response.status < 500) {
        if (data.errors && data.errors.length > 0) {
          const errorMessages = data.errors
            .map(err => `${err.field}: ${err.message}`)
            .join(', ');
          throw new Error(errorMessages);
        }
        throw new Error('Client error occurred');
      }

      // Retry server errors (5xx)
      if (response.status >= 500) {
        throw new Error(`Server error: ${response.status}`);
      }

      // Check for errors even with 200 status
      if (data.errors && data.errors.length > 0) {
        const errorMessages = data.errors
          .map(err => `${err.field}: ${err.message}`)
          .join(', ');
        throw new Error(errorMessages);
      }

      return data;

    } catch (error) {
      lastError = error;

      // Only retry on server errors (5xx)
      if (error.message.includes('Server error') && attempt < maxRetries - 1) {
        // Exponential backoff: 1s, 2s, 4s
        const delay = Math.pow(2, attempt) * 1000;
        console.log(`Retry attempt ${attempt + 1} after ${delay}ms`);
        await new Promise(resolve => setTimeout(resolve, delay));
      } else {
        break;
      }
    }
  }

  throw new Error(`Request failed after ${maxRetries} attempts: ${lastError.message}`);
}

Best Practices

Handle all error cases

Don’t just handle successful responses. Plan for and gracefully handle all possible error scenarios.

Implement exponential backoff

For 5xx errors and timeouts, use exponential backoff with jitter to avoid overwhelming the server.

Log errors comprehensively

Include timestamps, request details, and full error responses in your logs for easier debugging.

Don't retry client errors

4xx errors indicate issues with your request. Retrying won’t help - fix the request instead.

Monitor API health

Track error rates and response times to detect issues early.

Validate before sending

Validate data client-side before making API requests to catch issues early and reduce unnecessary requests.

Debugging

Enable verbose logging
Test with cURL
Verify environments
Check API key validity

Log all requests and responses to diagnose issues:

console.log('Request:', url, options);
console.log('Response:', response);

Isolate issues by testing endpoints with cURL:

curl -v https://app.withforerunner.com/api/v1/properties \
  -H "Authorization: Bearer YOUR_API_KEY"

Confirm your API key is valid by making a simple GET request to /api/v1/properties

Getting Help

If you’re experiencing issues not covered in this guide:

Check API status

Verify there are no ongoing incidents or maintenance

Review your request

Confirm all required parameters are included
Verify data types and formats match documentation
Check authentication header is correct

Gather debugging information

Request ID from error response
Full error message and status code
Example request that reproduces the issue
Timestamp when error occurred

Contact support

Email engineering@withforerunner.com with your debugging information

Getting started

API reference

Integration

Overview

HTTP Status Codes

Success Codes

Client Error Codes

Server Error Codes

Error Response Format

Example Error Responses

Common Errors

Authentication Errors (401 Unauthorized)

Request Blocked by WAF (403 Forbidden)

Validation Errors

Resource Errors

File Upload Errors

Implementing Error Handling

Basic Error Handling

Exponential Backoff for Retries

Best Practices

Debugging

Getting Help

Getting started

API reference

Integration

Documentation Index

​Overview

​HTTP Status Codes

​Success Codes

​Client Error Codes

​Server Error Codes

​Error Response Format

​Example Error Responses

​Common Errors

​Authentication Errors (401 Unauthorized)

​Request Blocked by WAF (403 Forbidden)

​Validation Errors

​Resource Errors

​File Upload Errors

​Implementing Error Handling

​Basic Error Handling

​Exponential Backoff for Retries

​Best Practices

​Debugging

​Getting Help

Overview

HTTP Status Codes

Success Codes

Client Error Codes

Server Error Codes

Error Response Format

Example Error Responses

Common Errors

Authentication Errors (401 Unauthorized)

Request Blocked by WAF (403 Forbidden)

Validation Errors

Resource Errors

File Upload Errors

Implementing Error Handling

Basic Error Handling

Exponential Backoff for Retries

Best Practices

Debugging

Getting Help