What Flash Temp Mail does and who it is for
Flash Temp Mail (now operating under the TempmailBee brand) exposes a REST API for managing the full lifecycle of a disposable email address. Rather than screen-scraping a temp-mail website or spinning up your own mail infrastructure, you call a handful of endpoints to create an inbox, poll it for incoming messages, download attachments, and eventually delete everything — all in a few hundred milliseconds per call.
The primary audiences are:
- Developers building user-registration or email-verification features who need realistic inboxes during testing without burning real addresses.
- QA and automation teams running sign-up flows against staging environments at scale.
- Businesses validating email marketing campaigns or optimizing onboarding sequences.
With 4,823 marketplace subscribers and a popularity score of 9.9 out of 10, Flash Temp Mail is one of the more widely adopted disposable-email APIs available — a signal that it holds up under real-world developer workloads.
Endpoint walkthrough
Flash Temp Mail exposes ten endpoints across two logical groups: mailbox management and message handling.
Mailbox management
| Endpoint | Method | What it does |
|---|---|---|
/mailbox/create |
POST | Creates a mailbox. You can supply a specific username and domain or let the API generate a random address. |
/mailbox/extend-time |
POST | Extends the mailbox expiry by 5 minutes. Can be called an unlimited number of times, so effective lifetime is unbounded if you keep polling. |
/mailbox/delete |
DELETE | Destroys the mailbox along with all its messages and attachments. |
/mailbox/list-all |
GET | Returns all active mailboxes tied to your API key. Useful for tracking open sessions. |
/mailbox/domains |
GET | Lists every domain currently available for mailbox creation, including which are free-tier vs. premium. |
/health |
GET | Reports API health status — handy for uptime checks in your own monitoring pipeline. |
Message and attachment handling
| Endpoint | Method | What it does |
|---|---|---|
/mailbox/emails |
GET | Returns all received emails as structured data (JSON). |
/mailbox/emails-html |
GET | Same as above but body content is returned as rendered HTML, saving you a parse step in browser-facing UIs. |
/mailbox/download-email |
GET | Downloads the raw email as an .eml file, useful when you need full MIME fidelity. |
/mailbox/download-attachment |
GET | Retrieves a specific attachment from a message. |
The distinction between /mailbox/emails and /mailbox/emails-html is a small but thoughtful touch. If you are building a UI that renders mail content inside an iframe or a webview, the HTML variant removes a server-side rendering step. The .eml download endpoint is less common in competing APIs and is worth noting if you need to replay or archive messages.
The /mailbox/extend-time design deserves attention: starting at a 10-minute lifetime and extending in 5-minute increments rather than setting an absolute expiry means you can keep a mailbox alive exactly as long as a test run requires without over-provisioning.
Domain tiers
Flash Temp Mail operates a two-tier domain system. Free users draw from a pool of general-purpose domains, while paid subscribers get access to premium brand-name domains limited to .com, .net, .co, and .org TLDs — no .xyz or .site domains that many services block at registration. The provider states 100+ premium domains are being added gradually, and you can always query /mailbox/domains to see the current list rather than relying on static documentation.
Pricing breakdown
| Plan | Monthly cost | Request quota | Overage rate | Rate limit |
|---|---|---|---|---|
| BASIC | $0 | 500 / day | $0.0010 / req | Not specified |
| PRO | $10 | 20,000 / month | $0.0009 / req | 5 req/sec |
| ULTRA | $50 | 250,000 / month | $0.0004 / req | 10 req/sec |
| MEGA | $125 | 3,000,000 / month | No overage listed | 20 req/sec |
A few things stand out here. First, the BASIC tier counts requests daily (500/day ≈ 15,000/month), while paid plans measure monthly — a meaningful difference if you have variable traffic patterns. Bursty usage in a single day on the free tier hits the wall faster than 15,000 monthly requests would suggest.
Second, the overage pricing drops significantly as you move up: $0.0010 on BASIC vs. $0.0004 on ULTRA. If your volume is inconsistent, sitting on ULTRA and paying overage at $0.0004 per request can be cheaper than upgrading to MEGA.
Third, MEGA has no listed overage rate, implying the 3,000,000-request allocation is likely intended to be sufficient for high-volume production use. At 20 requests per second, MEGA handles substantial parallel workloads — roughly 1.7 million requests per day at sustained peak throughput.
Practical use cases
Automated sign-up testing: Create a mailbox, register with the generated address in your test suite, poll /mailbox/emails until the verification email arrives, extract the link, and delete the mailbox. The 67 ms average latency keeps these loops tight.
Email marketing QA: Send a campaign to a batch of addresses created via /mailbox/create, then retrieve each inbox to verify rendering, link hygiene, and spam-filter behavior without polluting real subscriber lists.
Onboarding flow analytics: Use the API in a staging environment to confirm that transactional emails fire in the right order, contain correct dynamic content, and arrive within acceptable windows before a production release.
Attachment verification: If your app sends PDFs, CSVs, or images as email attachments, /mailbox/download-attachment lets you programmatically assert that file content is correct as part of a CI pipeline.
Limitations and things to check before integrating
- Free tier is daily-capped, not monthly. Five hundred requests per day is adequate for light local development but will constrain any CI system that runs full test suites on every commit.
- No rate limit is documented for BASIC. Before relying on burst behavior in free-tier tests, confirm the actual concurrency limit with support at [email protected].
- Premium domains are paid-only. If your test targets a service that blocks common temp-mail domains, you will need at minimum the PRO plan to access the premium TLD pool.
- Mailbox lifetime starts at 10 minutes. Long-running tests need to call
/mailbox/extend-timeperiodically, which itself consumes request quota. - MEGA has no listed overage, so understand whether requests beyond 3,000,000 are hard-blocked or billed before scaling to that tier.
Getting started
Flash Temp Mail is available through the RapidAPI marketplace. Sign up, subscribe to the BASIC plan for zero cost, and start with a POST /mailbox/create call — no configuration beyond an API key is required. Use /mailbox/domains to explore available domains before designing address generation logic. The /health endpoint is worth wiring into your integration tests so failures surface as infrastructure issues rather than application bugs.
Given the 100% documented success rate and sub-70 ms latency, the API is production-ready for any application that can absorb the per-plan request limits.
