Free public API — no auth required

Know your email
lands in the inbox

Send a test email. Get a deliverability report with SpamAssassin analysis, SPF, DKIM, and DMARC validation. Scored 0–10.

API Documentation How it works

Three steps. That's it.

No signup. No API key. No configuration.

1

Create a test

One POST request. Get a unique test address back.

$ curl -X POST \
spamchap.com/api/v1/tests
2

Send your email

From your server to the test address. A real delivery.

To test-a1b2c3@spamchap.com
From you@yourdomain.com
Subj Hello world
3

Get your score

Detailed breakdown across every check. Instantly.

Score
9.5/10
SpamAssassin
SPF
DKIM
DMARC
Headers
Let an AI run it for you

Or let your AI do it

Paste this into Claude, ChatGPT, or any AI assistant. It runs the whole test and explains your score — no commands to type.

AI agent prompt 
Use SpamChap (https://spamchap.com) - a free, no-auth API - to test my email deliverability. Follow these steps:

1. Create a test:
   POST https://spamchap.com/api/v1/tests
   From the JSON response, read data.email_address (like test-xxxx@spamchap.com) and data.test_id.

2. Show me the email_address and ask me to send a message to it from the address or server I want to test. Wait until I confirm I have sent it.

3. Poll for the result:
   GET https://spamchap.com/api/v1/tests/{test_id}
   Repeat every 10 seconds until data.status is "completed" (it moves pending -> processing -> completed). Give up after 5 minutes.

4. When completed, tell me data.score (out of 10), then go through each item in data.results (SpamAssassin, SPF, DKIM, DMARC, Headers): say what passed or failed and its score_impact. For anything that failed, explain in plain English how to fix it.

Score guide: 9-10 = inbox-ready, 7-8.9 = good, below 7 = likely landing in spam.

Works with any assistant that can make web requests. Your email is never stored beyond the test window.

What gets analysed

Twelve scored checks, weighted by impact on deliverability — plus ARC, TLS and BIMI reported for information.

35%

SpamAssassin

100+ rules

Content analysis for spam patterns, suspicious links, formatting, and known spam signatures.

12.5%

SPF

RFC 7208

Full RFC 7208 evaluation of your sending IP against the published record.

12.5%

DKIM

crypto

Cryptographic signature verification plus From-domain alignment and key strength.

12.5%

Blocklist (IP)

Your sending IP checked against six DNS blocklists, IPv4 and IPv6.

5%

DMARC

Record discovery, identifier alignment and how strict your published policy is.

5%

Domain blocklist

Your From domain and linked domains checked against DBL, SURBL and URIBL.

5%

Reverse DNS

PTR record for the sending IP and forward-confirmation of that name (FCrDNS).

2.5%

MX

Your From domain can actually receive replies and bounces.

2.5%

List-Unsubscribe

RFC 8058

One-click unsubscribe headers now required by Gmail and Yahoo bulk senders.

2.5%

Links

Broken links, URL shorteners, insecure http and anchor-text mismatches.

2.5%

HTML

Plain-text alternative, image-to-text balance and Gmail clipping size.

2.5%

Headers

Required headers plus Reply-To and Message-ID sanity checks.

Score interpretation

Higher is better. Here's what the numbers mean.

0–6.9
Needs work
Likely hitting spam folders
7.0–8.9
Good
Room for improvement
9.0–10
Excellent
Inbox placement expected

Start testing

No signup. No rate limits for reasonable usage. The API is free and public.

Read the docs
$ curl -X POST spamchap.com/api/v1/tests