canitsend-client 1.0.0

Client for the CanItSend API — SPF/DKIM/DMARC audit from live DNS, SPF flattening, and email validation.

canitsend-client

Zero-dependency Python client for the CanItSend API. Two questions, one API.

pip install canitsend-client

Every endpoint needs an API key. The free tier includes 100 audits/month — instant and self-serve: https://canitsend.com/#pricing

from canitsend import CanItSendClient
cis = CanItSendClient(api_key="snd_live_...")

1. Can my domain send?

a = cis.check("acme.com")          # also accepts "[e-mail]" or a URL
print(a["grade"], a["score"])      # F 40

# Plain-language answer to "but my email works!"
print(a["explanation"]["headline"])
# -> "Your mail works — but you can't prove you sent it."

# The exact records to paste, chosen for YOUR detected mail provider
for r in a["suggestedRecords"]:
    print(r["type"], r["host"], r["value"])
# -> TXT @       v=spf1 include:_spf.google.com ~all
# -> TXT _dmarc  v=DMARC1; p=none; rua=mailto:[e-mail]

The SPF 10-lookup limit

Over 10 DNS lookups means PermError — SPF fails entirely, not partially. We count it correctly: mx costs 1, not one per MX host. Most tools get this wrong.

spf = cis.spf_check("acme.com")
print(spf["lookupCount"], "/ 10", "PermError!" if spf["lookupLimitExceeded"] else "")

print(cis.spf_flatten("acme.com")["flattened"])   # zero include-lookups

2. Should I send to this address?

v = cis.validate("[e-mail]")
print(v["verdict"])      # risky
print(v["didYouMean"])   # [e-mail]

cis.validate("[e-mail]")   # risky   - disposable
cis.validate("[e-mail]")      # risky   - role account
cis.validate("[e-mail]")         # invalid - no MX, will bounce

What we don't claim: we do not verify the mailbox exists and do not detect catch-alls. Both require an SMTP probe on port 25, which we deliberately do not run. mailboxVerified is always False. The strongest verdict is deliverable_domain — the domain accepts mail.

Bulk (Agency+): audit_bulk([...]) up to 100 domains · validate_bulk([...]) up to 1,000 addresses.

Errors raise CanItSendError with .status and .problem (RFC 9457).