render-domains

Render custom-domain setup guidance for websites hosted on Render, including DNS records, root and wildcard domains, and HTTPS certificates.

In plain words
What is it for?
Use it to add a domain to a Render web service or static site, configure DNS, choose between a root and www address, set up wildcard domains, or troubleshoot HTTPS.
Why use it?
It helps avoid common domain-verification and certificate problems when replacing a Render-provided address with your own domain.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/render-oss/render-plugin-claude-code/render-domains
Any agent
npx skills add render-oss/render-plugin-claude-code --skill render-domains
Clone the repo
git clone --depth 1 https://github.com/render-oss/render-plugin-claude-code

Made for: Claude Code, Codex.

Per session 101 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,370 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00101 $0.01370
Opus 5 $0.00051 $0.00685
Sonnet 5 $0.00020 $0.00274
Haiku 4.5 $0.00010 $0.00137

Measured 2d ago against content hash ef6dc4bd1c66, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

render-domains scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/render-domains/SKILL.md · 152 lines

How it starts

The opening of the file, as written. The whole thing — 152 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Render Custom Domains

Render automatically provisions and renews TLS certificates (via Let's Encrypt and Google Trust Services) for all custom domains. All HTTP traffic is redirected to HTTPS. Custom domains work on web services and static sites only.

When to Use

  • Adding a custom domain to a web service or static site
  • Configuring DNS records (CNAME, A, or ALIAS) with a provider
  • Setting up a wildcard domain (*.example.com)
  • Troubleshooting certificate issuance or domain verification failures
  • Choosing between apex (example.com) and www (www.example.com)
  • Disabling the onrender.com subdomain after adding a custom domain

Domain Limits

Workspace tier Custom domain limit
Hobby 2 custom domains (across all services)
Professional+ Unlimited

Setup Steps

1. Add domain in Dashboard

  1. Go to your service's Settings > Custom Domains
  2. Click + Add Custom Domain
  3. Enter your domain (e.g. app.example.com)
  4. Click Save

Adding a www subdomain automatically adds the root domain (and vice versa) with a redirect between them.

2. Configure DNS

Add a DNS record with your provider pointing to your Render service:

Domain type Record type Name Value
Subdomain (app.example.com) CNAME app <service>.onrender.com
Apex (example.com) on Cloudflare CNAME (flattened) @ <service>.onrender.com
Apex on other providers A @ Use Render-provided IP (see Dashboard)

Important: Remove any AAAA (IPv6) records for your domain. Render uses IPv4, and stale AAAA records cause unexpected behavior.

Provider-specific guides:

3. Verify domain

Read the full file on GitHub · 152 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 152 lines · 101 tokens per session scan A ef6dc4bd1c66

Subscribe to this mod's changes

render-domains is a skill published in the GitHub repository render-oss/render-plugin-claude-code (0 stars, last pushed 13d ago), licensed MIT. It adds 101 tokens to every session and 1,370 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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