SMS Compliance API

The compliance layer
for SMS platforms

Your users send messages. You take the risk. Houdini filters non-compliant content before it reaches carriers — protecting your platform from SHAFT violations and filtering.

Become a Design Partner How it works
Message Analysis
Status Blocked
Violation SHAFT — Alcohol
Carrier Verizon
Action Message held for review

Built for platforms like

SimpleTexting FollowUpBoss Klaviyo Attentive Salesmsg

The Problem

Your platform. Their content. Your liability.

Carriers block aggressively

SHAFT content — Sex, Hate, Alcohol, Firearms, Tobacco — triggers immediate filtering. One bad campaign can tank your deliverability.

Rules vary by carrier

What passes on AT&T might get blocked on T-Mobile. Each carrier maintains different content policies, and they change without notice.

Manual review doesn't scale

You can't read every message. Compliance teams are expensive. Bad content slips through until you're already blocked.

The Solution

A compliance firewall for your SMS pipeline

Houdini sits between your users and the carriers. Every message gets checked against SHAFT rules and carrier-specific policies before it goes out.

Your User
Houdini
Carrier

Integration

One API call before every send

Pass your message through Houdini before delivery. Get back a compliance verdict with specific violations — in milliseconds.

  • SHAFT content detection
  • Carrier-specific rules
  • Clear violation explanations
  • Block, warn, or log — your choice 
const result = await houdini.check({
  message: content,
  carrier: "verizon"
});

// Response
{
  "compliant": false,
  "violations": [{
    "rule": "SHAFT_ALCOHOL",
    "severity": "high",
    "detail": "Alcohol promotion"
  }],
  "action": "block"
}

Coverage

SHAFT compliance and carrier rules

S

Sex

Adult content, explicit material, dating spam

H

Hate

Hate speech, harassment, discrimination

A

Alcohol

Alcohol promotion and unregulated marketing

F

Firearms

Weapons sales, ammunition, related content

T

Tobacco

Tobacco, vaping, cannabis promotion

+

Carrier Rules

Carrier-specific policies beyond SHAFT

Pricing

Design partner program

We're building Houdini with a small group of SMS platforms. Free access while we build, preferential pricing when we launch.

Early Access

Help us build the right product

Free during beta
  • Full API access
  • Direct line to founders
  • Shape the roadmap
  • Locked-in pricing at launch
Apply for Early Access

Become a design partner

We're looking for 5–10 SMS platforms to build Houdini with. You get early access and input on the product. We get real-world feedback.

We'll reach out within 24 hours to learn about your use case.