How to Ignore SSL with cURL: 4 Methods & Security Tips 2025

When working with cURL to fetch data from development servers, self-signed endpoints, or legacy systems, you may encounter SSL certificate errors that block your requests. This guide shows you how to ignore SSL verification with cURL in various scenarios—while emphasizing best practices and security considerations to keep your pipelines robust.

Why cURL Ignores SSL and When to Use It

By default, cURL enforces SSL/TLS certificate validation to protect you from man-in-the-middle (MitM) attacks and ensure data integrity. However, in certain non-production situations, certificate errors arise:

• Development/Test Servers with self-signed certificates
• Expired or Misconfigured Certificates during migrations
• Internal APIs behind corporate firewalls without a public CA

In these cases, you can temporarily bypass SSL checks, fetch your resources, and resume proper validation once certificates are updated.

For more basics of cURL, you can check our blog How to Use cURL with Proxy.

Four Methods to Ignore SSL with cURL

Method	Description	Recommended For
1. One-Off Command Bypass	Use -k or --insecure on a single curl invocation.	Quick tests or one-time requests
2. System-Wide Configuration	Add insecure (and proxy-insecure if needed) to your ~/.curlrc so every curl skips verification.	Frequent testing in development
3. Proxy-Specific Bypass	Combine -k/--insecure with --proxy-insecure (and -x <proxy>) when the proxy itself has certificate issues.	Working behind self-signed proxies
4. Scripted Requests in Code	Disable verification in your application’s cURL bindings (e.g., CURLOPT_SSL_VERIFYPEER = false in PHP, or c.setopt(c.SSL_VERIFYPEER, 0) in PycURL).	Developers automating API calls

New to cURL?

Quick test → Method 1

Working in development regularly → Method 2

Behind a corporate proxy → Method 3

Automating in code → Method 4

Method 1. One-Off Command Bypass

The simplest way to ignore SSL errors in a single cURL invocation is using the -k or --insecure flag:

bash

 

# Bypass SSL checks for this request only

curl -k https://self-signed.example.com/api/data

 

# Equivalent long-form flag

curl --insecure https://self-signed.example.com/api/data

This skips certificate chain validation and hostname checks just for that invocation.

Method 2. System-Wide cURL Configuration

If you often work with untrusted certificates, configure cURL to ignore SSL by default.

Note: This exposes every cURL call on your account to MitM risk, so use cautiously.

1. Open (or create) your cURL config file:

bash

 

vi ~/.curlrc

2. Add the following lines:

nginx

 

insecure

3. (Optional) For proxy connections that also use self-signed certs:

 

proxy-insecure

All subsequent curl calls from your user will bypass SSL checks.

Method 3. Proxy-Specific SSL Bypass

When your proxy itself uses a self-signed or invalid certificate:

bash

 

curl \

  -x http://proxy.local:8080 \

  -k --proxy-insecure \

  https://example.com

• -x sets the proxy
• --proxy-insecure ignores the proxy’s SSL cert
• -k ignores the target site’s SSL cert

Method 4. Scripted Requests in Code

PHP (cURL Extension)

php

 

$ch = curl_init('https://self-signed.example.com');

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);

curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);

$response = curl_exec($ch);

curl_close($ch);

Python (PyCURL)

python

 

import pycurl

from io import BytesIO

 

buffer = BytesIO()

c = pycurl.Curl()

c.setopt(c.URL, 'https://self-signed.example.com')

c.setopt(c.WRITEDATA, buffer)

c.setopt(c.SSL_VERIFYPEER, 0)

c.setopt(c.SSL_VERIFYHOST, 0)

c.perform()

c.close()

print(buffer.getvalue().decode())

These examples disable both peer and host verification programmatically in your scripts.

Alternative: Trust a Specific CA

Rather than disabling SSL entirely, you can trust a custom Certificate Authority (for internal CAs):

1. Download the CA certificate (e.g., internal-ca.pem).

2. Use --cacert to point cURL at it:

bash

 

curl --cacert internal-ca.pem https://internal-api.example.com

3. For proxies with their own CA:

bash

 

curl --proxy-cacert proxy-ca.pem --insecure https://example.com

This approach maintains TLS security while trusting only your designated CA.

Security Considerations

! Disabling SSL verification opens you to serious risks:

• Man-in-the-Middle Attacks: This can intercept and alter data.
• Data Integrity Loss: You can’t be sure the response is genuine.
• Trust Erosion: Bypassing checks in production undermines overall security.

Best practice: Restrict -k or --insecure to development, testing, or debugging. Always enable full validation in production environments.

Advanced Network Troubleshooting

If SSL bypass doesn’t resolve the error, network issues may be at play:

1. Flush DNS Cache

bash

 

# macOS

sudo dscacheutil -flushcache

# Windows

ipconfig /flushdns

2. Check Proxy/Firewall Rules

Ensure your proxy or firewall permits HTTPS over port 443.

3. Inspect cURL Debug Output

bash

 

curl -v -k https://example.com

Review handshake logs to diagnose TLS failures or handshake mismatches.

FAQ

Q: Can I combine --insecure and --cacert?

A: Yes. --insecure ignores system CAs, while --cacert uses only your specified CA.

Q: Why doesn’t -k work with HTTP/2?

A: Check that your cURL build supports HTTP/2 (curl --version). If not, recompile with --with-nghttp2.

Preventive Measures

Maintain Valid Certificates: Automate renewals via Let’s Encrypt or your CA.

Use Trusted CAs: Avoid self-signed certs in public or production systems.

Implement Monitoring: Alert on certificate expiry or misconfiguration.

Adopt Certificate Pinning: In clients, pin known-good certificates to detect unexpected changes.

Final Thoughts

Mastering cURL ignore SSL lets you work smoothly with non-standard SSL setups while preserving security best practices. Use one-off flags for quick tests, global configs for frequent dev work, and CA-based approaches for safer long-term use. Always revert to full verification in production.