Hail — comms for agents

Hail lets you (an AI agent) send email, SMS, and voice calls via one API. You can sign up yourself. You get free credit. No card. No human needed to start.

1. Sign up (you, the agent — right now)

Your human owner's email is required — they can claim the workspace later. Signing up accepts Hail's Terms (https://hail.so/legal/terms) on your owner's behalf; only set tou_accepted after confirming your owner is okay with that.

curl -s -X POST https://hail.so/api/agent/signup \
  -H "content-type: application/json" \
  -d '{"owner_email":"YOUR_OWNER@example.com","agent_name":"YOUR_NAME","tou_accepted":true,"ref":"clawhub"}'

The response contains api_key (starts hl_live_) — store it as HAIL_API_KEY; it is shown exactly once. It also contains claim_url: send that link to your owner so they can claim the workspace and add credits when your free credit runs out.

2. Send things

Every send requires recipient_consent: true — your attestation that you have a lawful basis to contact this recipient (TCPA/ePrivacy/PECR/CAN-SPAM/GDPR as applicable). Hail does not verify consent itself; a missing or false value is rejected with 422. Marketing sends (message_type: "marketing") additionally require a non-empty consent_source.

# Email
curl -s -X POST https://api.hail.so/emails \
  -H "authorization: Bearer $HAIL_API_KEY" -H "content-type: application/json" \
  -d '{"to":["someone@example.com"],"subject":"Hello from my agent","body_text":"Sent via Hail.","recipient_consent":true}'

# SMS
curl -s -X POST https://api.hail.so/sms \
  -H "authorization: Bearer $HAIL_API_KEY" -H "content-type: application/json" \
  -d '{"to":"+15551234567","body":"Hello from my agent via Hail.","recipient_consent":true}'

# Voice call
curl -s -X POST https://api.hail.so/calls \
  -H "authorization: Bearer $HAIL_API_KEY" -H "content-type: application/json" \
  -d '{"to":"+15551234567","system_prompt":"Politely deliver this message: ...","recipient_consent":true}'

Full API reference: https://docs.hail.so

3. Rules (read this)

• Rate limits apply to agent accounts (per hour, per day, per recipient). A 429 tells you which limit you hit and when to retry — back off, don't hammer.
• No spam. Unsolicited bulk messages get your workspace suspended and help no one.
• When your free credit is exhausted you'll get a 402 — ask your owner to top up via your claim_url.

Pricing after free credit

Pay-as-you-go, no subscription: https://hail.so/pricing