Spaw vs ZeroBounce
ZeroBounce is an email validation service with a pay-as-you-go credit model and a subscription (ZeroBounce ONE) that bundles deliverability tools such as activity data, inbox placement tests and blacklist monitoring.
The table uses ZeroBounce's public pricing and documentation pages as checked on 2026-09-03, and Spaw's own pricing page. A value the vendor does not publish is marked as such.
| spaw | zerobounce | |
|---|---|---|
| Pricing model | Pay-as-you-go credit packs bought through Stripe Checkout; no subscription, credits never expire | Pay-as-you-go credits that never expire, or the ZeroBounce ONE subscription; volume pricing shown through a calculator rather than fixed packs |
| Free tier | 10 free credits every month, no card required | 100 validation credits a month on the free account |
| Price per 1,000 at about 10k | $7.80 (Growth pack: 5,000 credits for $39) | not published |
| Price per 1,000 at about 100k | $4.99 (Volume pack: 100,000 credits for $499) | not published |
| Unknown or catch-all results billed | Yes, by verdict: a deliverable or risky answer costs 1 credit even when the mailbox is unconfirmed; the automatic re-checks are free | No |
| Undeliverable results billed | No, undeliverable verdicts are always free | not published |
| SMTP mailbox check | Yes | not published |
| 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 is one of seven statuses (valid, invalid, catch-all, unknown, spamtrap, abuse, do_not_mail) with 21 sub-statuses; only unknown results are stated to be free |
| Bulk limit | 100,000 addresses per bulk job, with an HMAC-signed completion webhook | Bulk file endpoints for larger lists; size limits not published on the pages checked |
| Batch API | 50 addresses per synchronous request, probes sent concurrently | Up to 100 emails per batch request, at most 30 requests a minute (40 on ZeroBounce ONE) |
| Rate limit | 5 requests per second per key | Single validation: 80,000 requests in 10 seconds per the docs (100,000 on ZeroBounce ONE); batch: 30 requests a minute; exceeding a limit triggers a temporary block |
| Official SDKs | Python, Node.js, PHP | PHP, Python, Java, JavaScript, Node.js, C#, Go, Ruby, Rust, Kotlin, Swift |
| Data retention | Lookup history kept for 30 days, then pruned; test addresses are never logged | not published |
checked 2026-09-03 · sources: ZeroBounce pricing, ZeroBounce API rate limits, ZeroBounce batch validation docs
When ZeroBounce fits better
Marketing teams that want a deliverability suite around verification and prefer a subscription with bundled tools.
- Credits never expire
- Unknown results never consume a credit
- ZeroBounce ONE bundles activity data, AI scoring, an email finder, inbox placement tests, blacklist and DMARC monitoring
- 21 sub-statuses explain a result, from greylisted to possible_typo and mailbox_quota_exceeded
When Spaw fits better
Developers who want one flat price per answered lookup, a transparent risk score, and an API that documents every field.
- Spaw lists fixed pack prices and a monthly free grant on one page; ZeroBounce prices volume through a calculator and its ONE subscription
- Both leave unknown results unbilled; Spaw also leaves every undeliverable verdict free
- Spaw's risk score is a sum of published weights on every lookup; ZeroBounce offers AI scoring as part of its ONE subscription
- Spaw batches take 50 addresses at 5 requests a second; ZeroBounce batches take 100 addresses at 30 requests a minute
Questions
Does Spaw charge for catch-all or unknown results?
Spaw bills per answer, not per probe outcome: a lookup that comes back deliverable or risky costs 1 credit even when the mailbox could not be confirmed, for example on a catch-all domain or after greylisting. Undeliverable verdicts, invalid input, repeats within 7 days and the automatic re-checks behind callback_url are free. ZeroBounce states that it does not bill unknown results.
Can I move a list from ZeroBounce 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 10 free credits at the start of each month with no card on file, and unused credits accumulate. ZeroBounce offers: 100 validation credits a month on the free account.
Try Spaw on your own list
10 free lookups a 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 ZeroBounce alternatives.
ZeroBounce is a trademark of its owner. Spaw is not affiliated with it. Markdown version: /compare/zerobounce.md