Verified
Resend's own API skill: send transactional and batch email, handle inbound webhooks, and manage domains, templates, and keys.
ResendEmailTransactional
APIs & Integrations × Codex
Top APIs & Integrations Skills for Codex
For API integration work in Codex CLI, the verified set is vendor-first: Paddle for merchant-of-record billing, Twilio for messaging, Resend for transactional email, and WorkOS for enterprise auth flows. Anthropic's system-design skill is the one to add when the question is how the integration should be shaped rather than which SDK call to make.
6 of 17 verified on Codex · updated June 22, 2026
Top 5 on Codex
- 1.resend—Resend's own API skill: send transactional and batch email, handle inbound webhooks, and manage domains, templates, and keys.
Resend's own API skill: send transactional and batch email, handle inbound webhooks, and manage domains, templates, and keys.
Full-stack WorkOS implementation with auth provider migration paths.
Drop-in WorkOS widgets with backend token wiring across every major framework.
- 4.paddle-agent-skills—Paddle's own integration playbook: ten skills for Checkout, webhooks, pricing pages, and subscription lifecycle on the merchant-of-record platform.
Paddle's own integration playbook: ten skills for Checkout, webhooks, pricing pages, and subscription lifecycle on the merchant-of-record platform.
- 5.twilio—Twilio's official Developer Kit: 55 skills across SMS, WhatsApp, Voice, Verify, SendGrid, and compliance — plus the Twilio MCP. Public beta.
Twilio's official Developer Kit: 55 skills across SMS, WhatsApp, Voice, Verify, SendGrid, and compliance — plus the Twilio MCP. Public beta.
Verified
APIs & Integrations skills that work on Codex
Ranked by composite score. Every entry was tested on Codex — not inferred from the SKILL.md format.
Official
Drop-in WorkOS widgets with backend token wiring across every major framework.
WorkOSWidgetsAuth
Verified
Paddle's own integration playbook: ten skills for Checkout, webhooks, pricing pages, and subscription lifecycle on the merchant-of-record platform.
PaddleSubscriptionsMerchant of Record
Verified
Twilio's official Developer Kit: 55 skills across SMS, WhatsApp, Voice, Verify, SendGrid, and compliance — plus the Twilio MCP. Public beta.
TwilioSMSWhatsAppVoice
Official
System design from requirements. APIs, data, boundaries, scale.
System DesignArchitectureAPI
Install
Commands for Codex
Copy-paste installs for the top picks. Full per-agent commands are on each skill page.
resend
codex skills add resend/resend-skills/skills/resend-emailworkos
Not bundled with Codex; community port may exist.
workos-widgets
Not bundled with Codex; community port may exist.
paddle-agent-skills
codex plugin marketplace add PaddleHQ/paddle-agent-skillstwilio
codex skills add twilio/ai/skills/twilio-skillssystem-design
Copy the system-design folder into ~/.codex/skills/
Not verified here
11 apis & integrations skills we have not confirmed on Codex
Listed rather than hidden. Absence here usually means untested, not broken — check each skill page for the agents it is verified on.
- stripe-best-practices
- stripe-projects
- connect-recommend
- stripe-directory
- webhook-skills
- composio
- hubspot-agent-skills
- box
- block-kit
- fhir-developer-skill
- hubspot-admin-skills
A combination only gets a page here when at least 6 skills are verified on the agent — otherwise the page would be a stub pretending to be a ranking.
FAQ
Common questions
Why is this list shorter than the same category for Cursor?
Because it lists only what was verified on Codex, not everything that plausibly works. Several vendor skills in this category have been tested on Claude Code and Cursor but not yet on Codex — they are absent here by policy rather than because they failed. The category page shows the full set with per-agent badges.
How many apis & integrations skills work with Codex?
6 of the 17 skills catalogued in APIs & Integrations are verified working on Codex. The remaining 11 are either untested on this agent or depend on capabilities it does not provide — they are listed below rather than hidden.
How do I install a apis & integrations skill on Codex?
Each skill page carries the exact Codex command. Codex reads SKILL.md natively, so a skill folder works unchanged.
Related
Other cuts of this data
- All APIs & Integrations skills →
Every entry in the category, across all agents, ranked by composite score.
- All skills for Codex →
Every skill verified on Codex CLI, across all categories.
- Top Code Quality & Review Skills for Codex →
The 10 code review agent Skills with verified Codex compatibility, ranked by composite score, with the install command for Codex and what is not verified there yet.
- Top Frontend & UI Design Skills for Codex →
The 9 frontend & ui agent Skills with verified Codex compatibility, ranked by composite score, with the install command for Codex and what is not verified there yet.