AWS Route 53 is AWS’s DNS service and domain registrar - the ‘53’ comes from DNS port 53 (which Route 53’s own docs explain). It does three things: domain registration, DNS resolution, and health checking. The team that uses Route 53 as both registrar and DNS avoids glue records and split-brain domain management. The team that uses Cloudflare or external DNS has a different story.
Table of contents
The ‘53’ name
DNS runs on UDP/TCP port 53. AWS named the service ‘Route 53’ as a clever reference to the historical US airmail Route 66 - except for DNS, you’d use port 53. The team’s mental model: Route 53 = DNS for AWS.
The team that asks ‘why is it called 53’ now knows - it’s the DNS port number.
Hosted zones
A hosted zone is a container for DNS records for a domain. Route 53 has two types:
- Public hosted zone: resolvable from the public internet. Costs $0.50/month per zone.
- Private hosted zone: only resolvable from associated VPCs. Free.
The team that creates a public hosted zone for example.com gets 4 name servers to update at the registrar. The team that uses a private hosted zone for internal.example.com has VPC-only DNS.
Record types
Common records:
- A: IPv4 address (e.g.,
203.0.113.42) - AAAA: IPv6 address
- CNAME: alias to another hostname (e.g.,
app.example.com -> elb.amazonaws.com) - MX: mail server (e.g.,
10 mail.example.com) - TXT: arbitrary text (SPF, DKIM, domain verification)
- NS: name server records (set at registrar)
- CNAME vs ALIAS: ALIAS is a Route 53-specific record that works at the zone apex (
example.comitself, where CNAMEs aren’t allowed).
The team that uses ALIAS for example.com -> elb.amazonaws.com works around the CNAME-at-apex restriction. The team that uses CNAME for subdomains (app.example.com) is fine.
Routing policies
Route 53’s traffic-routing value is in the policies:
- Simple: one record, one target. Default.
- Weighted: split traffic by percentage (e.g., 90% to v1, 10% to v2 - for canary deploys).
- Latency: route to the region with lowest latency for the user.
- Geolocation: route based on user’s continent/country (for content licensing).
- Geoproximity: route based on bias (Route 53 Traffic Flow only).
- Failover: active/passive between primary and secondary (uses health checks).
- Multi-value: return up to 8 healthy records (poor man’s load balancing).
The team that uses failover routing for primary/DR has automatic cutover on health check failure. The team that uses weighted for canary deploys controls the rollout percentage.
Health checks
Route 53 health checks ping your endpoint from 15 global checkers. If a threshold (default 3/3) fail, the record is marked unhealthy and traffic routes to the failover (if configured).
The team that uses health checks for failover has automated DR. The team that has health checks but no failover policy just sees an alert in the Route 53 console - no automatic action.
Domain registration
Route 53 can register and renew domains. TLDs vary in price ($12/year for .com, more for .io and .ai).
The team that registers through Route 53 has automatic DNS setup (the zone is created during registration). The team that uses an external registrar (Namecheap, Google Domains) has glue records to manage manually.
FAQ
What’s the difference between Route 53 and Cloudflare DNS?
Cloudflare DNS is faster (anycast network) and includes DDoS protection and CDN. Route 53 has tighter AWS integration (ALB, S3, VPC) and traffic-routing policies. The team that uses Cloudflare in front of AWS gets both - Cloudflare for DNS/CDN, Route 53 for AWS-specific routing.
How much does Route 53 cost?
$0.50/month per public hosted zone, $0.40/million queries (first billion), $0.60/million for latency-based queries. The team with a single domain pays ~$0.50/month for the zone plus per-query costs.
Can Route 53 be used for non-AWS endpoints?
Yes - the target can be any IP or hostname. The team that uses Route 53 for on-prem or multi-cloud DNS has a single pane of glass.
What happens during a Route 53 outage?
DNS queries are cached upstream (TTL-based). A short TTL (60s) means faster recovery when Route 53 returns. Long TTLs (24hr) cache longer but delay recovery. The team that needs fast failover uses low TTLs on critical records.
How do I migrate DNS from another provider?
Lower TTL to 60s at the old provider 24-48 hours before the move. Create the same records in Route 53. Update registrar NS records to Route 53’s name servers. The team that skips the TTL pre-step has extended downtime during the move.
If you are sizing the infrastructure for the kind of project this post covers, the RunxBuild hosting calculator is the right place to model the line items. The compute, the memory, the storage, the bandwidth, the database - each one is a separate number, and the team’s mental model for the platform is the sum of those numbers. The RunxBuild dashboard is where the team sees the actual usage in one place.
Useful related references: