Oauth
Sets up OAuth providers to work with portless local dev URLs by switching from rejected .localhost subdomains to valid TLDs like .dev or .app. Google and Apple are the main culprits here, they reject .localhost in redirect URIs even though they allow bare localhost. The skill walks through configuring Google, Apple, Microsoft, Facebook, and GitHub with the right callback URLs, plus how to set NEXTAUTH_URL and similar vars so your auth library constructs URLs correctly. If you've ever hit "redirect_uri_mismatch" during local OAuth testing, this is the fix. Includes a table showing exactly which providers block what, which is honestly useful reference material on its own.
- skills.sh installs
- 3.1K
- GitHub stars
- 12.9K
- last updated
- Aug 21, 2026
Install
$ npx -y skills add vercel-labs/portless --skill oauth --agent claude-codeInstalls into .claude/skills of the current project.
Files
OAuth with Portless
OAuth providers validate redirect URIs against domain rules. .localhost subdomains fail on most providers because they are not in the Public Suffix List or are explicitly blocked. Portless fixes this with --tld to serve apps on real, valid domains.
The Problem
When portless uses the default .localhost TLD, OAuth providers reject redirect URIs like http://myapp.localhost:1355/callback:
| Provider | localhost | .localhost subdomains | Reason |
|---|---|---|---|
| Allowed | Rejected | Not in their bundled PSL | |
| Apple | Rejected | Rejected | No localhost at all |
| Microsoft | Allowed | Allowed | Permissive localhost handling |
| Allowed | Varies | Must register each URI exactly | |
| GitHub | Allowed | Allowed | Permissive |
Google and Apple are the strictest. Microsoft and GitHub are more lenient with localhost.
The Fix
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- Repository
- github.com/vercel-labs/portless
- Categories
- Security, Git & Pull Requests, Cloud & Infrastructure
- First seen
- May 16, 2026
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