Sonjj API Documentation
Real Gmail and Outlook inboxes — not throwaway domains that get blocked. One header to authenticate, three endpoints to operate, credits charged only on HTTP 200.
Most temp email APIs hand out disposable domains that signup forms reject — silently, before a single message is even attempted. SmailPro hands out real Gmail and Outlook addresses, which is why they actually land. One header to authenticate, three endpoints to operate, credits deducted only on a successful response.
This page is the overview — no endpoint listings, no code samples. Full API reference lives at the docs hub; pricing at sonjj.com/pricing.
Real Gmail and Outlook — Why It Matters
Services like Tempmail.com, Guerrilla Mail, and Maildrop hand out addresses on generic disposable domains. Salesforce, HubSpot, and most modern signup forms maintain blocklists of these domains — your test request is dropped before the email is even attempted. The failure is silent: no error, no bounce, just a form that never gets verified.
SmailPro works differently. The pool runs on about 3,000 real Gmail accounts and about 11,000 real Outlook accounts, across maintained provider-domain pools. The API rotates assignment so no single address takes repeated load. The pool also includes selected .edu.pl addresses for education-domain testing where allowed.
The result: stronger observed acceptance on production signup forms that reject obvious disposable domains. Internal checks consistently show provider-domain inboxes outperforming generic temp mail, but acceptance varies by platform, behavior, geography, and verification rules.
Three Calls. One Header. No SDK.
Authentication is a single X-Api-Key header. Copy the key from your my.sonjj.com dashboard, drop it in the header, and you're making requests. No OAuth flow, no SDK to install, no session cookie to maintain. Works with cURL, Python requests, Go's net/http, n8n HTTP node — anything that speaks HTTP.
The full flow is three calls:
- Create an inbox — get back a real Gmail or Outlook address.
- Poll the inbox for new messages — IMAP-synced every 5–10 seconds.
- Read a message — get the full body or pull out the OTP directly.
The API is receive-only by design. It doesn't send mail — intentionally. Cleaner deliverability, a smaller abuse surface, and predictable behavior for test automation and CI/CD pipelines.
Pay for Results, Not Attempts
Credits are deducted only on a successful response. 4xx, 5xx, timeouts — nothing is charged. You pay for results, not attempts.
Per-call costs are transparent:
| Call | Cost |
|---|---|
| Inbox poll | 0.05 credits |
| Inbox create | 1 credit |
| Read message | 1–2 credits |
The base rate is $1.00 per 1,000 credits. At scale it drops to $0.30 per 1,000 credits — a 70% reduction. No monthly fees. Credits never expire, so buying ahead carries no risk.
The same credit balance covers SmailPro, YChecker, UGener, SMSer, StoreGmail, CardGener, and any other Sonjj product. One wallet, draw from it wherever you need it. More detail: How Sonjj credits work.
By the Numbers.
- 400,000+ messages received
- 200,000+ inboxes created
- Sub-10 seconds OTP delivery — IMAP syncs every 5–10s
- 14,000+ real Gmail and Outlook accounts in active rotation
- ~3,000 Gmail + ~11,000 Outlook maintained provider-domain inboxes
- High observed acceptance on production signup forms that block disposable domains
Built and dogfooded by Sonjj — the same API powering internal testing across 7 products.
API Claim Notes
Delivery speed, acceptance, and pool availability are operational metrics, not hard guarantees. Gmail and Outlook accounts are continuously rotated and maintained. API usage is receive-only: it is built for creating inboxes, polling messages, and reading verification content, not sending email or handling attachments.
Where to Go Next
If you want to dig deeper before integrating:
- Temporary email tool — try the receive-only Gmail/Outlook flow before integrating
- How SmailPro compares to Guerrilla Mail, Mailinator, and TempMail — side-by-side on domain trust, pricing model, and CI/CD fit
- SmailPro for QA, marketing, and security teams — team-level use cases and infrastructure details
- Security and privacy limits — understand retention, receive-only access, and attachment limitations
- How Sonjj credits work across products — per-endpoint cost breakdown, expiry policy, and cross-product usage
New endpoints, pool refreshes, and pricing changes ship quietly. Subscribe to the Sonjj newsletter to hear about them first.
Real Gmail and Outlook, one header, pay-on-success — that's the whole pitch. Pick your next step: