Question 1

Is Let's Encrypt truly free, and what's the catch?

Accepted Answer

Yes, Let's Encrypt certificates are entirely free. There is no catch; the service is provided by a non-profit organization (Internet Security Research Group - ISRG) with the mission to make HTTPS ubiquitous. Funding comes from sponsorships and donations. The primary 'cost' is the requirement to use an ACME client for automated issuance and renewal, which integrates into server management workflows rather than a manual web interface.

Question 2

What is the validity period for a Let's Encrypt certificate, and how does renewal work?

Accepted Answer

Let's Encrypt certificates are valid for 90 days. This shorter validity period is intentional, promoting automation and minimizing the impact of compromised keys. Renewal is designed to be fully automated via ACME clients, which should be configured to attempt renewal well before expiration (e.g., 30 days prior). This ensures continuous HTTPS coverage without manual intervention.

Question 3

Can I use Let's Encrypt for commercial websites or high-traffic services?

Accepted Answer

Absolutely. Let's Encrypt certificates are trusted by all major browsers and are suitable for any type of website, including commercial, high-traffic, and enterprise-level services. The security strength of the certificates is equivalent to those from commercial CAs. The primary difference is the automated, programmatic issuance model rather than a manual purchase and installation process.

Question 4

What domain validation methods does Let's Encrypt support?

Accepted Answer

Let's Encrypt primarily supports two domain validation methods: HTTP-01 and DNS-01. HTTP-01 requires placing a specific file on your web server at a known URL, which Let's Encrypt then fetches. DNS-01 requires creating a specific TXT record in your domain's DNS, which Let's Encrypt queries. DNS-01 is necessary for wildcard certificates and can be more convenient for servers not directly exposed to the internet.

Question 5

How does Let's Encrypt compare to traditional commercial Certificate Authorities?

Accepted Answer

Let's Encrypt provides domain-validated (DV) certificates, which offer the same level of encryption and browser trust as DV certificates from commercial CAs. The key differences are that Let's Encrypt certificates are free, have a 90-day validity period (encouraging automation), and are issued via the ACME protocol, requiring an ACME client. Commercial CAs often offer longer validity periods, manual issuance options, and extended validation (EV) or organization validation (OV) certificates, which Let's Encrypt does

Let's Encrypt Website Full Guide (2026)

Introduction

Key Features

Use Cases

Automating TLS Provisioning in CI/CD

How to Use Let's Encrypt

Select and Install an ACME Client

Let's Encrypt Alternatives

OWASP

Malwarebytes

Krebs on Security

VirusTotal

About Let's Encrypt

Official Website

Video Mentions

Let's Encrypt Status