Spaw vs Mailboxlayer
Mailboxlayer is apilayer's email validation API, sold as monthly request quotas from a free 100-request plan up to 250,000 requests a month.
The table uses Mailboxlayer's public pricing and documentation pages as checked on 2026-09-13, and Spaw's own pricing page. A row those pages carry no value for is marked "not on the pages read" rather than guessed at, and that is a statement about the reading and not about what Mailboxlayer publishes.
| spaw | mailboxlayer | |
|---|---|---|
| Pricing model | Pay-as-you-go credit packs whose credits never expire, or optional plans, billed monthly or yearly, that deposit the same credits every month for less and roll unused plan credits over up to three months' allowance; both through Stripe Checkout | Monthly or yearly subscription (10 to 15% off yearly) with a request quota per plan and per-request overage |
| Free tier | 100 free credits every month, no card required | 100 requests a month |
| Price per 1,000 at about 10k | $7.80 (Growth pack: 5,000 credits for $39), or $5.80 on the Growth monthly plan (5,000 credits for $29 a month) | $3.00 for the Basic quota (5,000 requests for $14.99 a month; overage $0.012 a request, so 10,000 requests on Basic cost about $74.95, $7.50 per 1,000); Professional Plus: 50,000 for $74.99, $1.50 per 1,000 |
| Price per 1,000 at about 100k | $4.49 (Volume pack: 100,000 credits for $449), or $3.49 on the Volume monthly plan (100,000 credits for $349 a month) | $1.50 to $1.00 (Professional Plus: 50,000 requests for $74.99, overage $0.006 a request; Enterprise Plus: 250,000 for $249.99, overage $0.004) |
| Unknown or catch-all results billed | No: an unconfirmed mailbox (reason unverified) and an answer Spaw could not obtain because its handshake partner was unavailable are free and leave no 7-day repeat marker, so a later lookup is a fresh one; a catch-all answer costs 1 credit like any risky answer, and an automatic re-check bills 1 credit only when it confirms the mailbox | Yes |
| Undeliverable results billed | No, within a fair use: undeliverable answers that needed a mailbox probe are free up to max(500, your billed email answers) in a rolling 30 days, then 1 credit each; the rest are always free | Yes |
| SMTP mailbox check | Yes | Yes |
| Catch-all handling | A catch-all answer is remembered per domain for 7 days, and every unconfirmed mailbox carries a published 0 to 100 mailbox_confidence estimate | Catch-all detection from the Basic plan up, not on Free; every request counts against the quota |
| Bulk limit | 100,000 addresses per bulk job, with an HMAC-signed completion webhook | Bulk endpoint: 25 emails per request on Professional Plus, 100 on Enterprise Plus |
| Batch API | 50 addresses per synchronous request, probes sent concurrently | 25 or 100 emails per request depending on plan |
| Rate limit | 5 requests per second per key on the email and consistency endpoints | not on the pages read |
| Official SDKs | Python, Node.js, PHP | not on the pages read |
| Data retention | Only email verification keeps a history row, for 30 days, then pruned; test addresses are never logged | not on the pages read |
checked 2026-09-13 · sources: Mailboxlayer product and pricing
When Mailboxlayer fits better
Developers who prefer a flat monthly quota and already use other apilayer APIs.
- SMTP check, MX records, syntax and typo validation, and the free and disposable databases on every plan including Free; catch-all detection from Basic up
- 256-bit HTTPS encryption listed for paid plans
- Part of the apilayer marketplace
When Spaw fits better
Developers who want one flat price per answered lookup across every signal a signup form produces, a transparent risk score, and an API that documents every field.
- Mailboxlayer counts every request against a monthly quota; Spaw bills only answered lookups and leaves unverified mailboxes free, and undeliverable verdicts free within a fair-use allowance
- Spaw's bulk jobs take 100,000 addresses; mailboxlayer's bulk endpoint takes 25 or 100 per request depending on plan
- Spaw includes the SMTP handshake on every lookup including the free monthly grant; mailboxlayer's SMTP check is on every plan too, while its catch-all detection starts at Basic
- At high volume mailboxlayer's quota price of $1.00 to $1.50 per 1,000 is below Spaw's $4.49 on the 100,000 pack and $3.49 on the Volume plan
Questions
Does Spaw charge for catch-all or unknown results?
Spaw bills per answer, not per probe outcome. A catch-all domain comes back risky with reason catch_all and costs 1 credit like any risky answer. A mailbox the handshake could not confirm (greylisting, a timeout, no definite answer) comes back risky with reason unverified and is free, and so is an answer Spaw could not obtain at all because its handshake partner was unavailable; neither leaves a 7-day repeat marker, so a later lookup is a fresh one (an uncertain result is reused for up to 15 minutes, then the mailbox is asked again) and bills 1 credit only once the mailbox is confirmed, and the automatic re-checks behind callback_url bill 1 credit only when they confirm it. Undeliverable verdicts are free within a fair use of max(500, your billed email answers) in a rolling 30 days, and invalid input and repeats within 7 days are free too. Mailboxlayer counts them according to its public pages.
Can I move a list from Mailboxlayer to Spaw?
Yes. Upload the CSV to the dashboard or POST it to the bulk endpoint; Spaw keeps your columns, adds the verdict columns, and lets you download only the deliverable, risky or undeliverable rows. Addresses that come back undeliverable join your suppression list so later runs skip them for free.
Is there a free tier?
Every Spaw account receives 100 free credits at the start of each month with no card on file, and unused free credits accumulate. Mailboxlayer offers: 100 requests a month.
Try Spaw on your own list
Free credits every month, no card. Upload a list, keep your columns, and download only the rows you want. See the pricing page for every rule, or the Mailboxlayer alternatives.
Mailboxlayer is a trademark of its owner. Spaw is not affiliated with it. Markdown version: /compare/mailboxlayer.md