One command
Add Postmark to any Ashlr Stack project with a single command. Stack runs the auth flow, verifies the credential, and writes every secret slot into Phantom.
stack add postmark
Or describe what you're building and let Claude pick it up via stack recommend:
stack recommend "transactional email for my app"Auth flow
Paste a long-lived API key once. Stack verifies it against the provider's API before writing to Phantom.
How-to: Paste an account token from https://account.postmarkapp.com/api_tokens.
Secret slots
stack add postmark writes these 1 secret
slot into your Phantom vault:
POSTMARK_ACCOUNT_TOKEN
The values never leave Phantom in plaintext. Your .env file references slot
names, and stack exec -- <cmd> swaps them in at process-spawn time via
Phantom's local proxy.
Related providers in Email
- Resend — Transactional + React Email. API key stored in Phantom.
- SendGrid — High-volume transactional mail. API key verified against /v3/scopes on paste.
- Mailgun — API-first email + routing. Key verified against /v3/domains on paste (HTTP Basic).
FAQ
Do I need a Postmark account to use it with Stack?
Yes — Stack provisions Postmark on your behalf, but it authenticates as you. Paste a long-lived API key once. Stack verifies it against the provider's API before writing to Phantom. If you don't have a credential yet, create one at https://account.postmarkapp.com and paste it once.
Where does Stack store my Postmark credentials?
In Phantom Secrets, an E2E-encrypted local vault. Stack writes the secret slot names (POSTMARK_ACCOUNT_TOKEN) into .stack.toml — the actual values live only in Phantom and never touch disk in plaintext.
Can I rotate or revoke this integration later?
Yes. Run `stack remove postmark` to pull the Postmark service back out (Phantom secrets deleted, MCP entry removed, .stack.toml cleaned up). Rotate the underlying Postmark credentials in their dashboard — https://account.postmarkapp.com — and Stack's next `doctor --fix` will pick up the new values.