Introduction
Running a platform that hosts thousands of subdomains presents unique operational challenges. Each subdomain has its own DNS records, SSL configuration, traffic patterns, and abuse history. At the scale of thousands of active subdomains, manual management is impossible. This post describes the systems and tools we use to manage is-pro.dev's subdomain fleet: from automated DNS provisioning to bulk record updates, monitoring, expiration management, and the custom tools we built to keep everything running smoothly.
Automated DNS Provisioning
When a user registers a subdomain on is-pro.dev, the entire DNS zone setup happens automatically. Our provisioning system calls Cloudflare's API to create the DNS zone, add the initial records (NS, SOA, default A/AAAA records pointing to a splash page), and configure SSL settings. The process takes under 2 seconds from when the user clicks "Register" to when their subdomain is live on Cloudflare's global network. The provisioning system handles edge cases: rate-limited API calls are retried with exponential backoff, zone creation failures trigger alerts to our operations team, and new zones are automatically added to our monitoring systems. We also maintain a pool of pre-configured zone templates so that common configurations (static site, API endpoint, email forwarding) can be applied with a single API call when the user selects a setup wizard option in the dashboard.
Bulk DNS Record Management
Occasionally we need to make changes across many subdomains at once — updating nameserver addresses, adding a new default record, or changing a security setting. Our internal admin tool provides a bulk operations interface: select subdomains by filter (creation date, traffic level, record type, etc.), preview the changes, and apply them in batches. The tool uses Cloudflare's API to apply changes efficiently, handling pagination and rate limits automatically. For sensitive changes (like modifying NS records), we require a two-person approval workflow. The bulk operations tool has saved hundreds of hours of manual work and reduced the error rate compared to individual subdomain management.
Monitoring at Scale
Every is-pro.dev subdomain is monitored for DNS resolution, SSL certificate validity, and HTTP response status. Our monitoring system checks each subdomain from multiple geographic locations at configurable intervals. When a subdomain fails a check, the system categorizes the failure: DNS resolution failure (nameserver not responding), SSL error (certificate expired or invalid), HTTP error (server returning 5xx), or content mismatch (response body does not match expected pattern). Alerts are routed based on severity: individual subdomain failures are logged and queued for daily review, while systemic failures (multiple subdomains failing simultaneously) trigger immediate alerts. The monitoring dashboard provides a real-time view of platform health with drill-down to individual subdomain status.
Expiration and Renewal Management
Free subdomains require periodic activity to remain registered. Our expiration management system tracks the last activity date for each subdomain and sends automated reminders at 30, 14, and 7 days before the inactivity threshold is reached. If a subdomain expires, it is moved to a grace period where DNS records are preserved but the subdomain is marked as inactive. After the grace period (30 days), DNS records are removed and the subdomain name is released back to the pool. The expiration system is fully automated but includes manual override capabilities: subdomains involved in abuse investigations or legal disputes can be frozen to prevent release. We also provide an API endpoint for users to programmatically renew their subdomains, which is useful for automated deployments and CI/CD pipelines.
Abuse Detection and Response Pipeline
Managing thousands of subdomains means dealing with abuse at scale. Our abuse detection pipeline operates in tiers: automated scanning identifies obvious violations (phishing templates, malware signatures, trademarked terms in subdomain names), community reports are triaged automatically based on reporter reputation and report content, and the operations team handles escalated cases. The pipeline uses machine learning classifiers trained on historical abuse data to prioritize reports — a report of a phishing page targeting a major bank receives immediate action, while a copyright claim on a blog post is queued for human review. The abuse system integrates with our DNS management API to suspend subdomains automatically when confidence is high, while flagging ambiguous cases for manual review.
Custom Tooling: The Admin Dashboard
We built an internal admin dashboard that provides a unified interface for managing all aspects of the subdomain fleet. The dashboard shows: total active subdomains, growth trends, abuse report volume, DNS health metrics, and SSL certificate status. From the dashboard, operators can search for any subdomain, view its complete DNS configuration, check recent traffic patterns, review abuse history, and perform administrative actions (suspend, reinstate, transfer ownership, modify DNS records). The dashboard also provides audit logging — every action is recorded with timestamp, operator identity, and before/after state. This audit trail is essential for investigating incidents and maintaining platform integrity.
Scaling Lessons Learned
Managing subdomains at scale has taught us several lessons. First, automation is non-negotiable — anything that can be automated should be automated, because manual processes do not scale and introduce errors. Second, monitoring must be multi-layered: synthetic checks from external locations catch issues that internal metrics miss. Third, rate limits are a constant consideration — every Cloudflare API call is metered, and we manage our API consumption carefully to avoid hitting limits during critical operations. Fourth, graceful degradation matters — when a subsystem fails (e.g., the abuse detection engine goes down), the rest of the platform must continue operating. Fifth, data retention planning is essential — DNS logs, abuse reports, and audit trails accumulate rapidly at scale, and we have automated retention policies that balance storage costs with operational needs.
Conclusion
Managing thousands of subdomains requires a combination of automation, monitoring, careful rate limit management, and custom tooling. The systems we have built allow us to operate is-pro.dev with a small team while maintaining high reliability and fast response to issues. Every component — DNS provisioning, monitoring, expiration management, abuse detection — is designed to operate at scale with minimal manual intervention. The lessons we have learned apply to any platform that manages distributed infrastructure at scale: automate everything, monitor at every layer, and build for graceful degradation from day one.
Key Takeaways
- Automated DNS provisioning creates subdomains in under 2 seconds via Cloudflare API
- Bulk operations tools manage thousands of subdomains with a single action
- Multi-layered monitoring catches failures at DNS, SSL, and HTTP levels
- Expiration management automates renewal reminders and graceful subdomain release
- Abuse detection combines automated scanning, community reporting, and ML-based triage
- Custom internal tools provide unified fleet management with full audit logging
- Automation, monitoring, rate limiting, graceful degradation, and data retention are the pillars of operating at scale
Frequently Asked Questions
Is is-pro.dev really free to use?
Yes, is-pro.dev provides free subdomains for developers with no hidden fees.
What can I host on an is-pro.dev subdomain?
Any legitimate project — portfolios, SaaS apps, game servers, APIs, and more.