Abstract API vs Mailboxlayer
Both are validation APIs priced by monthly request quota. Mailboxlayer's Basic plan is $14.99 a month for 5,000 requests. Abstract API's paid plans start at $17 a month. Mailboxlayer publishes a clearer ladder, up to 250,000 requests for $249.99. Abstract suits teams already using its other APIs.
Prices read from abstractapi.com and mailboxlayer.com. We sell a competing product, and it is not in the verdict above — where we fit is at the bottom.
| Abstract API | Mailboxlayer | |
|---|---|---|
| Cheapest route | $17/mo | $14.99/mo |
| Per year, if subscribed | $204 | $161.99 |
| Metering | Monthly request allowance | Monthly API request quota |
| Credits expire | Allowance resets monthly | Allowance resets monthly |
| Product type | Validation API | Validation API |
| Price checked | 2026-10-12 | 2026-10-12 |
Cost for one pass over a list
Each vendor’s cheapest available route. An empty cell means that vendor does not publish an allowance we can calculate from, not that it is free.
| List size | Abstract API | Mailboxlayer | Cheaper |
|---|---|---|---|
| 1,000 | — | $14.99 | Not comparable |
| 10,000 | — | $29.98 | Not comparable |
| 50,000 | — | $74.99 | Not comparable |
| 100,000 | — | $149.98 | Not comparable |
How each one bills you
Abstract API charges $17 a month, metered as monthly request allowance. Mailboxlayer charges $14.99 a month for 5,000 verifications, or $161.99 for a year, metered as monthly api request quota.
Abstract API's allowance is tied to the subscription period. Mailboxlayer's allowance is tied to the subscription period. For uneven volume, expiry often matters more than the headline price, because credits that lapse raise the real cost of every address you did verify.
What to watch with Abstract API: the plan is a request quota, so a bulk clean and your live sign-up checks compete for the same allowance. With Mailboxlayer: it is an API quota, not a list tool, so cleaning a CSV means writing the batching yourself and every row counts against the month.
Both meter verifications, so checking the same list again costs again. Before committing to either, verify an address you invented at a real domain and an address at a catch-all domain on both. The first should come back invalid and the second as risky or accept-all, not valid.
Choose Abstract API if
you already use Abstract's other APIs and want one key and one bill.
Disclosure — our product
Where SimpleVerifier fits, and where it does not
We publish this comparison and we sell a third option, so treat the rest of this section as the pitch it is. SimpleVerifier is a flat monthly price with unlimited email verifications and API access included, so there are no credits to buy or expire:
Pro $29.99/mo
Unlimited email verification, finder and phone format checks.
Email + Phone $49.99/mo
Everything in Pro, plus live carrier lookups for your phone lists.
That is worth it in two cases: large lists, because volume does not change the price, and lists you verify repeatedly, because a confirmed result is cached for 14 days so the second pass costs nothing. Outside those two cases, a metered vendor is usually cheaper and you should use one, Abstract API and Mailboxlayer included.
Common questions
- Abstract API or Mailboxlayer — which is better?
- Both are validation APIs priced by monthly request quota. Mailboxlayer's Basic plan is $14.99 a month for 5,000 requests. Abstract API's paid plans start at $17 a month. Mailboxlayer publishes a clearer ladder, up to 250,000 requests for $249.99. Abstract suits teams already using its other APIs.
- How much do Abstract API and Mailboxlayer cost?
- Abstract API costs $17 a month. Mailboxlayer costs $14.99 a month for 5,000 verifications, or $161.99 for a year. Both read from their own pricing pages — Abstract API on 2026-10-12, Mailboxlayer on 2026-10-12.
- Should I choose Abstract API?
- Choose Abstract API if you already use Abstract's other APIs and want one key and one bill.
- Should I choose Mailboxlayer?
- Choose Mailboxlayer if you want published request quotas at each price tier.
- Is there an alternative to both Abstract API and Mailboxlayer?
- SimpleVerifier is a flat monthly plan rather than credits: Pro at $29.99 a month or Email + Phone at $49.99 a month, with unlimited email verifications and API access included. It suits large lists and lists you re-check often. For a small one-off clean, a metered vendor such as Abstract API or Mailboxlayer can cost less.