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Abstract API alternative: when ContactLint fits and when it does not

Facts checked October 17, 2026

Abstract API and ContactLint answer different questions. Abstract API checks whether a mailbox exists. ContactLint checks whether an address is worth saving: is the syntax right, does the domain accept mail, is it a throwaway or role inbox, and is it a typo of a big provider. That smaller check is why it costs less.

The short answer

Stay with Abstract API if you need a live SMTP check, a quality score, sender and domain enrichment or breach data in one response, or you already use other Abstract APIs.
Choose ContactLint if you would rather buy one-time credit packs than a monthly plan, want email and phone checks on one key and one balance, or want a hosted MCP server from the vendor itself.

Abstract API sells monthly plans (Starter is $17 a month billed annually for 5,000 requests a month) and its phone validation is a separate API with its own plans. ContactLint sells one-time packs (5,000 checks for $9) and email and phone checks share one key and one balance. Abstract runs an SMTP check; ContactLint does not.

Side by side

	ContactLint	Abstract API
Confirms the mailbox exists (SMTP)	No. Syntax, DNS/MX, disposable, role and typo checks only; no SMTP connection, no catch-all detection	Yes, a live SMTP check without sending a message, plus catch-all flags (source)
Smallest purchase	5,000 checks for $9	Starter at $17 a month billed annually, 5,000 requests a month (source)
5,000 checks	$9	$17 a month billed annually (Starter, 5,000 requests a month) (source)
25,000 checks	$35	Not listed
100,000 checks	$99	Not listed
Free to start	100 checks every month, no card	100 requests, no card (source)
Unknown results	Not charged: any check whose DNS lookup fails is given back	Not listed
Credits expire?	No expiry in our terms; unused credits refundable within 14 days	Plan requests are per month or per year (source)
Typo suggestions	Yes, did_you_mean for major providers (gmial.com to gmail.com)	Yes, a suggested_correction field (source)
MCP server for AI agents	Hosted remote server at /mcp, nothing to install	No official server listed; a third-party open-source server exists (source)
Phone validation	Yes, same key and same credits	Separate Phone Validation API with its own plans (source)

Competitor facts read from each vendor's public pages on October 17, 2026 and linked in each cell. Prices change; follow the links for current terms. "Not listed" means the page we read did not state it, not that the vendor lacks it.

What switching looks like

Create a free key at /signup.
Replace one HTTP call: POST /v1/email/validate with {"email": "..."}, or /v1/email/validate/batch for up to 50 addresses.
Map verdicts: invalid reject, risky ask the user or review (show did_you_mean when set), valid accept, unknown accept or retry later.

curl -X POST https://contactlint.com/v1/email/validate \
  -H "Authorization: Bearer YOUR_KEY" -H "content-type: application/json" \
  -d '{"email":"jane@gmial.com"}'

Guides: server-side check on form submit, drop-in typo widget, email validation for AI agents.

Questions

Is ContactLint a full replacement for Abstract API?

Only if you do not need mailbox verification. Abstract API tests whether the mailbox exists; ContactLint checks syntax, DNS/MX, disposable domains, role addresses and typos, and never connects to mail servers.

Can I use ContactLint and Abstract API together?

Yes. A common split is ContactLint at the signup form or inside an AI agent, where volume is steady and a fast cheap check is enough, and a mailbox verifier for occasional deep cleans of an old list.

How do I try ContactLint?

Create a free key at contactlint.com/signup (100 checks per month, no card), or run a live check on the home page without a key.

How we made this page

Written by the ContactLint team. Abstract API facts were read from its public pages on October 17, 2026 and are linked in each table cell; we did not test its API. ContactLint facts come from our pricing and API spec. Spot something out of date? Email support@contactlint.com and we will fix it.

Get a free API key. 100 checks per month, no card required. Or try a live check first.