Curl Success But Wrong Response: Validate API Responses

Your curl command returns HTTP 200, but the response body contains an error message. Learn how to detect and handle this.

The Problem: HTTP 200 with Error Content

Many APIs return HTTP 200 even when there's an error, putting the error message in the response body. This breaks simple exit code checks:

API returns 200 OK with JSON error: {"error": "Invalid token"}
REST API returns 200 with HTML error page
GraphQL returns 200 with errors array in response
Webhook endpoints return 200 but log failures internally
Health check endpoints return 200 even when service is degraded

Checking only HTTP status code isn't enough. You need to validate the response body content.

Solution: Validate Response Body

Always check response content, not just HTTP status. Parse JSON responses and look for error fields, or search for error keywords in text responses.

Bash Example: Check JSON Response

#!/bin/bash
RESPONSE=$(curl -s -w "\n%{http_code}" "https://api.example.com/data")
HTTP_CODE=$(echo "$RESPONSE" | tail -n1)
BODY=$(echo "$RESPONSE" | sed '$d')
# Extract response validation data
HAS_ERROR=0
if echo "$BODY" | grep -q '"error"'; then
  HAS_ERROR=1
fi
# Single ping with response data in payload
# In DeadManPing panel: set validation rules:
#   - "status_code" == 200
#   - "has_error" == 0
# Panel will automatically detect violations and alert
curl -X POST "https://deadmanping.com/api/ping/api-check?status_code=$HTTP_CODE&has_error=$HAS_ERROR"

Python Example: Validate JSON Response

import requests
import json
response = requests.get("https://api.example.com/data")
# Extract response data for payload
has_error = False
try:
  data = response.json()
  has_error = "error" in data
except json.JSONDecodeError:
  has_error = True  # Invalid JSON
# Single ping with response data in payload
# In DeadManPing panel: set validation rules:
#   - "status_code" == 200
#   - "has_error" == False
# Panel will automatically detect violations and alert
requests.post(f"https://deadmanping.com/api/ping/api-check?status_code={response.status_code}&has_error={has_error}")

Node.js Example: Check Response Content

const https = require('https');
https.get('https://api.example.com/data', (res) => {
  let data = '';
  res.on('data', (chunk) => data += chunk);
  res.on('end', () => {
    // Extract response data for payload
    let hasError = false;
    try {
      const json = JSON.parse(data);
      hasError = !!json.error;
    } catch (e) {
      // Invalid JSON
    }
    // Single ping with response data in payload
    // In DeadManPing panel: set validation rules:
    //   - "status_code" == 200
    //   - "has_error" == false
    // Panel will automatically detect violations and alert
    https.request(`https://deadmanping.com/api/ping/api-check?status_code=${res.statusCode}&has_error=${hasError}`, { method: 'POST' }).end();
  });
});

GraphQL Example: Check Errors Array

#!/bin/bash
RESPONSE=$(curl -s -X POST "https://api.example.com/graphql" \
  -H "Content-Type: application/json" \
  -d '{"query": "{ query { data } }"}')
# Extract GraphQL response data
HAS_ERRORS=0
if echo "$RESPONSE" | grep -q '"errors"'; then
  HAS_ERRORS=1
fi
# Single ping with GraphQL response data in payload
# In DeadManPing panel: set validation rule "has_errors" == 0
# Panel will automatically detect if GraphQL response has errors
curl -X POST "https://deadmanping.com/api/ping/graphql-check?has_errors=$HAS_ERRORS"

Monitoring Response Validation

After adding response validation to your scripts, use a dead man switch to monitor whether validation completed successfully. If your script detects an error in the response body and exits with error code, the ping never arrives, and you get an alert.

Include error messages in your ping payload so you can track what types of errors occur and identify patterns.

Working Examples

See complete, working code examples in our GitHub repository:

View Examples on GitHub →

Start Monitoring API Responses

DeadManPing monitors whether your response validation completes. Set up monitoring in 2 minutes, get alerts when APIs return wrong responses.

Start Monitoring Free

Learn more about cron job monitoring and troubleshooting:

Curl Success But Wrong Response: Validate API Responses

The Problem: HTTP 200 with Error Content

Solution: Validate Response Body

Bash Example: Check JSON Response

Python Example: Validate JSON Response

Node.js Example: Check Response Content

GraphQL Example: Check Errors Array

Monitoring Response Validation

Working Examples

Start Monitoring API Responses

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