AI app builders

Use SuperSend TX in Lovable, Replit, Bolt, Base44, v0, and similar AI builders. Add your stx_… API key as a secret, paste the builder prompt, and let the agent wire POST /emails.

Pick your builder

Builder Best for Guide
Lovable React + Supabase apps, chat-driven features Secrets + agent prompt
Replit Full-stack Replit Agent projects Replit Secrets + agent prompt
Bolt.new Vite / React prototypes from chat .env + agent prompt
Base44 Base44 apps with optional custom email When to use TX vs built-in mail
v0 Next.js from Vercel v0 Route Handler + Vercel env

Before you paste a prompt

  1. Create a SuperSend TX account and an API key (stx_…).
  2. Store it as SUPERSENDTX_API_KEY in the builder’s secrets / env UI (server-side only).
  3. For a first send before your domain verifies, use the sandbox rules in Quickstart and Agent skill notes.

Standard env var

SUPERSENDTX_API_KEY=stx_your_key_here

Some builders also accept STX_API_KEY — if their UI suggests that name, map it to the same stx_… value. Prefer SUPERSENDTX_API_KEY in generated code for consistency with our SDK and docs.

Reference