# KaijuVerifier, free, POST /api/v1/verify-batch, Verify a batch synchronously: Email verification API

> Block fake signups, burner accounts, and hard bounces at the edge in 3 lines of code.

KaijuVerifier's email verification API on its Free plan. It costs $0.00 per 1,000 emails. It returns 3 of the 6 key fields we check: Address, Deliverability, Confidence.
We rank 2,467 plans by price. [treg's top-up from $10](https://datacircle.dev/validate-email-apis/treg/top-up-from-10/llms.txt) costs the least per 1,000 emails: $0.00 on average. treg asks one provider after another until one answers. You pay $26.95 per 1,000 emails when no provider answers.
[Enrich.so](https://datacircle.dev/validate-email-apis/enrich-so/149-monthly/llms.txt), [GetProspect](https://datacircle.dev/validate-email-apis/getprospect/369-pack/llms.txt) and [treg](https://datacircle.dev/validate-email-apis/treg/top-up-from-10/llms.txt) are the best email verification API providers in our benchmark.

- This page: https://datacircle.dev/validate-email-apis/kaijuverifier/free-post-api-v1-verify-batch-verify-a-batch-synchronously
- [Best email verification API in 2026](https://datacircle.dev/best-email-verification-api.txt)
- Get it: https://kaijuverifier.com/pricing
- Request: `POST https://kaijuverifier.com/api/v1/verify-batch`, Verify a batch synchronously
- API key: with the plan, on https://kaijuverifier.com/pricing
- Its API docs: https://kaijuverifier.com/api-docs
- Sold by: KaijuVerifier (https://kaijuverifier.com)
- Checked: 2026-10-20

## In the answer

- Completeness: 50%
- Address: ✓
- Deliverability: ✓
- Confidence: ✓

## Price

- $ per 1,000 emails: $0.00
- Per: result
- Billing: free

## Aggregators

- Aggregators: none

## Charges

- Also pays for: from the same budget: Verify a single email (authenticated) · Submit an async bulk job · Verify a single email with the SMTP probe (authenticated) · Verify a batch synchronously with the SMTP probe · Submit an async bulk job with the SMTP probe

## Not found

- $ per 1,000: $0.00

## Catch-all

- $ per 1,000: $0.00

## Bounce

- Bounce refund: the verification credits in full, when the campaign's hard-bounce rate exceeds 2% on addresses verified as Valid

## In their words

- Their pitch: Block fake signups, burner accounts, and hard bounces at the edge in 3 lines of code.

## Data

- Freshness: stored (DNS valid, MX count, MX providers, MX grade: live)
- Keep data: no limit
- Use data: You agree NOT to use the Service for: Sending SPAM or unsolicited bulk emails, Verifying email lists obtained illegally or without consent, Any activity that violates GDPR, CAN-SPAM, or other data protection laws, Attempting to reverse engineer, hack, or abuse the Service, Reselling or redistributing verification results without authorization

## Plan

- Pay: $0
- You get: 100 credits a month
- Enough for: 100 results a month

## Rate limit

- Batch: 10,000

## Speed

- Answer: in the call

## The call

- You send: emails. Optional: use_smtp
- Method: POST
- Path: /api/v1/verify-batch

## About the plan

- Plan: Free
- Who can get it: anyone

## The 28 fields the plan's answer can hold

success, batch ID, batch status, emails checked, valid emails, invalid emails, accuracy, email, normalized email, safe to send, status, reason, confidence, score, grade, did you mean, syntax valid, DNS valid, catch-all, disposable, role address, free provider, MX count, MX providers, MX grade, quota limit, quota used this month, quota remaining

## KaijuVerifier's plans (12)

- [KaijuVerifier, free, POST /api/v1/verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/free-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt): $0.00 per 1,000, 50% complete, stored (DNS valid, MX count, MX providers, MX grade: live)
- [KaijuVerifier, $19 pack, 5,000 Credits, POST /api/v1/verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/19-pack-5000-credits-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt): $3.80 per 1,000, 50% complete, stored (DNS valid, MX count, MX providers, MX grade: live)
- [KaijuVerifier, $79 pack, 25,000 Credits, POST /api/v1/verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/79-pack-25000-credits-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt): $3.16 per 1,000, 50% complete, stored (DNS valid, MX count, MX providers, MX grade: live)
- [KaijuVerifier, $249 pack, 100,000 Credits, POST /api/v1/verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/249-pack-100000-credits-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt): $2.49 per 1,000, 50% complete, stored (DNS valid, MX count, MX providers, MX grade: live)
- [KaijuVerifier, $899 pack, 500,000 Credits, POST /api/v1/verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/899-pack-500000-credits-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt): $1.798 per 1,000, 50% complete, stored (DNS valid, MX count, MX providers, MX grade: live)
- [KaijuVerifier, $19 monthly, Starter, POST /api/v1/verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/19-monthly-starter-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt): $1.90 per 1,000, 50% complete, stored (DNS valid, MX count, MX providers, MX grade: live)
- [KaijuVerifier, $49 monthly, Growth, POST /api/v1/verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/49-monthly-growth-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt): $0.98 per 1,000, 50% complete, stored (DNS valid, MX count, MX providers, MX grade: live)
- [KaijuVerifier, $149 monthly, Scale, POST /api/v1/verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/149-monthly-scale-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt): $0.596 per 1,000, 50% complete, stored (DNS valid, MX count, MX providers, MX grade: live)
- [KaijuVerifier, $182.04 yearly, Starter, POST /api/v1/verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/182-04-yearly-starter-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt): $1.517 per 1,000, 50% complete, stored (DNS valid, MX count, MX providers, MX grade: live)
- [KaijuVerifier, $470.04 yearly, Growth, POST /api/v1/verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/470-04-yearly-growth-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt): $0.783 per 1,000, 50% complete, stored (DNS valid, MX count, MX providers, MX grade: live)
- [KaijuVerifier, $1,430.04 yearly, Scale, POST /api/v1/verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/1430-04-yearly-scale-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt): $0.477 per 1,000, 50% complete, stored (DNS valid, MX count, MX providers, MX grade: live)
- [KaijuVerifier, contact us, Enterprise, POST /api/v1/verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/contact-us-enterprise-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt): 50% complete, stored (DNS valid, MX count, MX providers, MX grade: live)

## KaijuVerifier's calls (6)

- `POST /api/v1/jobs`, Submit an async bulk job: [KaijuVerifier, free, POST /api/v1/jobs, Submit an async bulk job](https://datacircle.dev/validate-email-apis/kaijuverifier/free-post-api-v1-jobs-submit-an-async-bulk-job/llms.txt)
- `POST /api/v1/jobs`, Submit an async bulk job with the SMTP probe: [KaijuVerifier, free, POST /api/v1/jobs, Submit an async bulk job with the SMTP probe](https://datacircle.dev/validate-email-apis/kaijuverifier/free-free-post-api-v1-jobs/llms.txt)
- `POST /api/v1/verify-batch`, Verify a batch synchronously: [KaijuVerifier, free, POST /api/v1/verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/free-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt)
- `POST /api/v1/verify-batch`, Verify a batch synchronously with the SMTP probe: [KaijuVerifier, free, POST /api/v1/verify-batch, Verify a batch synchronously with the SMTP probe](https://datacircle.dev/validate-email-apis/kaijuverifier/free-free-post-api-v1-verify-batch/llms.txt)
- `POST /api/v1/verify-single`, Verify a single email (authenticated): [KaijuVerifier, free, POST /api/v1/verify-single, Verify a single email (authenticated)](https://datacircle.dev/validate-email-apis/kaijuverifier/free-post-api-v1-verify-single-verify-a-single-email-authenticated/llms.txt)
- `POST /api/v1/verify-single`, Verify a single email with the SMTP probe (authenticated): [KaijuVerifier, free, POST /api/v1/verify-single, Verify a single email with the SMTP probe (authenticated)](https://datacircle.dev/validate-email-apis/kaijuverifier/free-free-post-api-v1-verify-single/llms.txt)

## KaijuVerifier's APIs (1)

- [KaijuVerifier: email verification API pricing, 12 plans, verify-batch, Verify a batch synchronously](https://datacircle.dev/validate-email-apis/kaijuverifier/free-post-api-v1-verify-batch-verify-a-batch-synchronously/llms.txt)

## KaijuVerifier: email verification API alternatives

- [Elastic Email, $189 monthly, Email API Pro (400,000 emails/month), POST /verifications/{email}](https://datacircle.dev/validate-email-apis/elastic-email/189-monthly-email-api-pro-400000-emails-month-post-verifications-email/llms.txt): $0.472 per 1,000, 50% complete, stored
- [IsItDisposable, $1,430 yearly, Pro, POST /v1/check](https://datacircle.dev/validate-email-apis/isitdisposable/1430-yearly-pro-post-v1-check/llms.txt): $0.477 per 1,000, 50% complete, stored
- [NexMailPro, $290 yearly, Pro, POST /verify/email](https://datacircle.dev/validate-email-apis/nexmailpro/290-yearly-pro-post-verify-email/llms.txt): $0.483 per 1,000, 50% complete, stored
- [ReefAPI, $450 quarterly](https://datacircle.dev/validate-email-apis/reefapi/450-quarterly/llms.txt): $0.50 per 1,000, 67% complete, stored

## Sources

From each provider's own pricing page and docs, and from what providers tell us. We read this row from these pages on 2026-10-20.

- https://kaijuverifier.com/api-docs
- https://kaijuverifier.com/dashboard/billing
- https://kaijuverifier.com/email-verification-api
- https://kaijuverifier.com/legal/notice
- https://kaijuverifier.com/legal/terms
- https://kaijuverifier.com/openapi.json
- https://kaijuverifier.com/pricing