# Spaw vs Bouncer: email verification API comparison

How Spaw and Bouncer compare on pricing, billing rules, verification depth and limits, from Bouncer's public pages checked on 2026-09-03. Corrections: support@spaw.co.

| | Spaw | Bouncer |
| --- | --- | --- |
| 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 (minimum 1,000 credits for $8), auto-refill, plus a Deliverability Kit subscription at $25 to $250 a month |
| Free tier | 10 free credits every month, no card required | 100 free credits, no card required |
| Price per 1,000 at about 10k | $7.80 (Growth pack: 5,000 credits for $39) | $6.00 (10,000 credits for $60) |
| Price per 1,000 at about 100k | $4.99 (Volume pack: 100,000 credits for $499) | $4.00 (100,000 credits for $400) |
| 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 | Yes |
| 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 | Returns an acceptAll domain property; unknown results and duplicates within a list are never charged |
| Bulk limit | 100,000 addresses per bulk job, with an HMAC-signed completion webhook | Up to 100,000 emails per batch (1,000 to 10,000 recommended); up to 60 batches a minute |
| Batch API | 50 addresses per synchronous request, probes sent concurrently | Synchronous batch of up to 10,000 emails at 100 requests a minute; asynchronous batches as above |
| Rate limit | 5 requests per second per key | Real-time API: 1,000 requests a minute by default |
| Official SDKs | Python, Node.js, PHP | Java |
| Data retention | Lookup history kept for 30 days, then pruned; test addresses are never logged | The batch and sync APIs keep a 24-hour cache so an address is not verified twice; a broader retention policy is not stated on the pages checked |

## When Bouncer fits better

Teams that want the lowest published per-check price with high batch throughput and a real-time form product.

- Bouncer Shield protects forms in real time
- Toxicity list checks
- Auto-refill and volume discounts

## When Spaw fits better

Developers who want one flat price per answered lookup, a transparent risk score, and an API that documents every field.

- Bouncer's published rates are $6.00 per 1,000 at 10,000 credits and $4.00 at 100,000; Spaw's are $7.80 and $4.99
- Both leave unknown results unbilled; Spaw also leaves undeliverable verdicts free
- Spaw's rate limit is 5 requests a second, 300 a minute; Bouncer's real-time API allows 1,000 a minute
- Spaw ships Python, Node.js and PHP clients plus an MCP server; Bouncer ships a Java client

## 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. Bouncer states that it does not bill unknown results.

**Can I move a list from Bouncer 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. Bouncer offers: 100 free credits, no card required.

## Sources (checked 2026-09-03)

- [Bouncer pricing](https://www.usebouncer.com/pricing/)
- [Bouncer batch API](https://docs.usebouncer.com/api-reference/batch/batch-create)
- [Bouncer batch sync API](https://docs.usebouncer.com/api-reference/batch-sync/batch-sync)
- [Bouncer real-time API](https://docs.usebouncer.com/api-reference/real-time/verify-email)
- [Bouncer integration guidelines](https://docs.usebouncer.com/integration-guidelines)

Bouncer is a trademark of its owner. Spaw is not affiliated with it.

Reference: https://spaw.co/compare/bouncer