Quickstart
Two paths to your first send. Pick the one that matches what you’re trying to do today.
Pick your path
| Path A — Try in 30s | Path B — Build for real | |
|---|---|---|
| Best for | Evaluating the API, demos, throwaway scripts | Production transactional email + dashboard for campaigns |
| Account needed | None — email-only widget | Free signup at app.brixus365.com/signup |
| Time to first send | 30 seconds | ~10 minutes (DNS for domain verification) |
| API key prefix | bx_preview_… | bx_live_… — requires a Standard or Enterprise plan |
| Send modes | Starter templates only | Starter templates + raw HTML + your saved templates + batch + SMTP |
| Sender | Fixed: noreply@brixus365.dev | Your verified domain |
| Send volume | 50/day, 1,500/month, 10/min (free) | 15,000/month and up on Standard |
| Spark (campaigns) | Not available | Available in dashboard (free) |
| Inbox & CRM (coming with WhatsApp/SMS) | Not available | Coming with WhatsApp/SMS launch |
Most developers start with Path A to verify the API contract works for them, then move to Path B once they’re committing to integration. The two paths share the same endpoints, error envelope, and code samples — your Path A code keeps working after you upgrade, just with a new key value.
Path A — Try in 30 seconds
Get a bx_preview_… key and send a starter template. No signup, no DNS, no waiting.
1. Get your free key
Open the developers page and look for the Get your free API key widget at the top.
- Enter your email address
- Open the verification email and click the confirm link
- Your
bx_preview_…key appears on the next screen — copy it now, the full value is shown only once
Save it as an env var so the snippets below just work:
export BRIXUS_API_KEY=bx_preview_your_key_here2. Send your first email
1curl -X POST https://app.brixus365.com/api/v1/emails \
2-H "X-API-Key: $BRIXUS_API_KEY" \
3-H "Content-Type: application/json" \
4-d '{
5 "to": "you@example.com",
6 "starterTemplate": "welcome",
7 "variables": { "name": "Friend", "app_name": "My App" }
8}'You’ll get back a messageId and status: "queued":
{
"messageId": "fd92bd3f-969a-4ff6-87dc-a8b0a16e0297",
"status": "queued",
"from": "noreply@brixus365.dev"
}
Check your inbox. The email arrives within a few seconds.
What you can and can’t do on Path A
| Can | Can’t |
|---|---|
Send any of the 10 starter templates | Send raw HTML or use your saved templates |
Look up message status via | Send from your own domain |
Test the MCP server with Claude / Cursor | Use the Spark campaigns dashboard |
Send up to 50/day, 1,500/month | Inbox & CRM (coming with WhatsApp/SMS) |
When you hit any of those limits, move to Path B — same API, more capability, on a Standard or Enterprise plan.
Path B — Build something real
Signup itself is free and gets you the dashboard, custom sending domains, and Spark campaigns you can build and send from the dashboard. Raw HTML sends, batch send, and the SMTP relay run on a live API key, which requires a Standard or Enterprise plan (see the checklist below). Setup takes ~10 minutes (mostly DNS records for domain verification).
Setup checklist
Path B has a 4-step setup before your first send works. Each step is described in detail in Before you send — here’s the summary:
| # | Step | Time |
|---|---|---|
| 1 | Sign up at app.brixus365.com/signup — verify your email with the OTP code | 2 min |
| 2 | Create an API key in Settings → API Keys → Create. Pick the Send emails (transactional) preset. | 1 min |
| 3 | Add a sending domain in Settings → Email Setup → Custom Email Domains and add the SPF + DKIM records to your DNS | 5–10 min (depends on DNS propagation) |
| 4 | Add a verified sender address and click Set as Default | 1 min |
Don’t skip step 4. The transactional API rejects sends with 403 no_verified_sender until at least one sender address is marked Default, even if your domain is verified.
Send your first production email
Once setup is complete, the same code as Path A works — just with your bx_live_… key. Sender will be your default verified address:
curl -X POST https://app.brixus365.com/api/v1/emails \
-H "X-API-Key: bx_live_your_key_here" \
-H "Content-Type: application/json" \
-d '{
"to": "customer@example.com",
"starterTemplate": "welcome",
"variables": { "name": "Alice", "app_name": "Acme" }
}'
Response:
{
"messageId": "dceaaa96-a806-43d2-ac2d-8396bbd3188a",
"status": "queued",
"from": "you@your-verified-domain.com"
}
What you can do on Path B
- Send via starter templates, your own saved templates, or raw HTML
- Send batches of up to 100 messages in one request
- Use the SMTP relay with any mail library (Nodemailer, PHPMailer, MailKit, etc.)
- Run Spark campaigns in the dashboard — drag-and-drop builder, automations, segments, analytics
- 15,000 sends/month and up on the Standard plan (required to create a live key), more on higher tiers
Spark (campaigns) is dashboard-only on free. Programmatic campaign sending requires a paid Standard plan. Transactional API + dashboard campaigns is what most teams need to start.
What’s next
| You want to… | Go to |
|---|---|
| See all 10 starter templates and their variables | Starter templates |
| Use a language we didn’t cover above | Code examples — 11 languages + SMTP |
| Send via SMTP from an existing mail library | SMTP relay |
| Wire Claude or another AI agent to send mail | MCP server quickstart |
| Understand error codes, rate limits, and idempotency | API overview |
| Walk through the Path B setup in detail | Before you send |
| Compare free vs paid plans | Pricing |
Stuck? Email support@brixus365.com — we read every message.