Managing TLS certificates at scale is one of those operational tasks that starts simple and quickly grows into a sprawling problem. As organizations adopt microservices, multi-tenant architectures, and globally distributed load balancers, the number of domains and subdomains they support can expand dramatically. Each certificate then requires its own lifecycle management:
- Creation
- Validation
- Renewal
- Deployment
- Rotation
Wildcard certificates offer a powerful solution to this growing complexity. Covering an entire namespace of subdomains with a single certificate dramatically simplifies management and can have great downstream efficiencies for your infrastructure.
In this article, we'll explore why wildcard certificates scale better, how they reduce pressure on load balancers, and why they're particularly beneficial in multi-tenant environments.
Refresher: What is A Wildcard Certificate?
A wildcard certificate is a TLS/SSL certificate that secures a domain and all of its first-level subdomains. So, instead of issuing a separate certificate for:
- api.example.com
- admin.example.com
- tenant1.example.com
- tenant2.example.com
A single wildcard certificate can be issued as *.example.com.
This certificate can then secure any subdomain under example.com, which makes it extremely flexible in large or dynamic environments.
Cycle supports both first level and nested wildcard certificate creation for DNS zones. Learn more about creating wildcard certs here .
Two Reasons Why Wildcard Certificates Scale Better Operationally
- Simplified Certificate Lifecycle Management
- Faster Onboarding of New Subdomains
Managing any more than a few dozen individual certificates can be really challenging. Yes, there are circumstances where this is required, and no, I'm not claiming that this should never be done… I am, however, going to say that if your use case does not demand individual certificates, using wildcards can be operationally superior by a large margin.
Let's look at this table to compare:
| Category | Wildcard Certificates | Individual Certificates |
|---|---|---|
| Number of Certificates | One certificate covers all subdomains | One certificate per subdomain |
| Expiration Events | Single renewal date to track | Many independent expiration dates (high risk of oversight) |
| Renewal Workflow | One automated workflow handles all subdomains | Each certificate requires its own issuance & renewal process |
| Deployment Complexity | Deploy one certificate across load balancers and services | Deploy many certs, often with different timelines and procedures |
| Secrets Management | Fewer private keys & cert files to store, rotate, and protect | A large volume of secrets increases operational + security burden |
| Failure Modes | Single point of failure if cert expires or key is compromised (mitigated by automation & secure storage) | Many small failure surfaces, any one cert can expire and break specific subdomains |
| Operational Overhead | Very low, centralized management | High, constant stream of renewals, updates, and deployments |
| Scaling Impact | Scales cleanly as new subdomains are added instantly | Scaling increases certificate count linearly, adding overhead |
| Onboarding Speed | Instant for new subdomains | Slowed by certificate issuance steps and CA rate limits |
| Load Balancer Impact | Fewer certs → simpler config and faster reloads | Lots of certs → larger configs, slower reloads, more sync traffic |
Reducing Pressure on Load Balancers
Load balancers often bear a surprising amount of TLS complexity, especially when operating at scale. For each unique domain or subdomain, the load balancer must store certificate material, reload its configuration when certificates update, and sometimes perform SNI routing.
Wildcard certificates significantly reduce this burden. Instead of storing dozens or hundreds of certificates, load balancers maintain only a few wildcard certs. In turn, this reduces:
- Memory usage
- Configuration size
- Startup and reload times
- Operational risk during rolling deployments
It's common for load balancers to perform a full configuration reload for certificate updates. When that load balancer manages hundreds (or more) certs, reload frequency and duration both increase. With wildcard certs, things can stay lean.
That also has an impact on highly available LB setups, or any load balancers that need to stay in sync across a distributed infrastructure. The less data required per sync, the lower the operational load and failure chances.
Fewer Certs -> Fewer Reloads -> Fewer Chances for Errors
Wildcard Certificates in Multi-Tenant Environments
Multi-tenant SaaS applications often rely on subdomains to isolate tenants, such as:
[tenant1.example.com](http://tenant1.example.com)
[tenant2.example.com](http://tenant2.example.com)
[tenant3.example.com](http://tenant3.example.com)Wildcards are a natural fit here. Instead of issuing a new certificate for each tenant during onboarding, one wildcard certificate can secure all tenant subdomains instantly. This means that new tenants can be brought online without waiting for certificate provisioning or dealing with the potential for a CA rate limit.
As the number of tenants grows, the benefits do as well. Managing certificates for hundreds or thousands of subdomains can easily overwhelm a platform team… especially when that team is faced with the constant renewal events, deployment steps, and secret rotation workflows (which introduce even more noise to the system).
Of course, wildcard certificates do come with important security considerations. Because a single private key protects every tenant's subdomain, that key must be handled with extreme care. If that key were to be leaked, it would compromise the entire domain. For this reason, wildcard certs work best when paired with strong key management practices:
- Secure storage
- Automated renewal
- Strict access controls
Best Practices for Wildcard Certificates
Wildcard certificates can be an essential tool in scaling modern infrastructure. Today, we talked through how they can help with reducing certificate sprawl, simplifying deployments, decreasing load balancer overhead, and accelerating multi-tenant onboarding. To wrap things up, let's take a look at a few best practices for using wildcard certificates.
To note: these following points are all fully automated for Cycle users!
Use ACME/Let's Encrypt Automation or Your Internal PKI
Automating certificate issuance and renewal ensures that your wildcard certificates are always up to date without relying on manual processes that are easy to forget or misconfigure. Whether you use ACME with Let's Encrypt or an internal corporate PKI, automation eliminates the risk of accidental expirations and allows you to incorporate certificate updates seamlessly into your deployment workflows.
Store Private Keys in Secure Vaults or Hardware-Backed Modules
Because a wildcard certificate covers many subdomains, its private key represents a high-value security asset. Storing this key in a secure location, such as an HSM, cloud KMS, or secrets manager, greatly reduces the chance of accidental exposure or compromise. Strong access controls, auditing, and hardware-backed protections ensure the integrity of the certificate and maintain trust across all dependent services.
Rotate Certificates Frequently
Regular rotation of wildcard certificates limits the potential damage if a private key is ever exposed and ensures cryptographic hygiene across your infrastructure. Automated rotation policies help keep keys fresh and encourage a security-first mindset while reducing the operational burden that often prevents teams from rotating certificates as often as they should.
Validate Deployment and Reload Pipelines
Even with a perfect certificate management strategy, issues can arise during deployment if your infrastructure doesn't reload or propagate certificates consistently. Testing and validating these reload paths—across load balancers, proxies, applications, and edge nodes, ensures that certificate updates are applied correctly and prevents stale certs from lingering in production.