Give your AI agents a voice.

Agent-callable messaging infrastructure for developers building with Claude, OpenAI, Gemini, Grok, Llama, Mistral, DeepSeek, Replit, and other AI platforms. One API sends SMS, email, and Telegram, verifies users during a conversation, and routes replies and events back into the agent.

Messaging infrastructure pricing

Pay-as-you-go is self-serve with no minimum: SMS $0.0079 per segment, email $0.001 per email, one sending domain, and one API key; MMS, RCS, Telegram, SHAFT, and restricted verticals require Scale. Standard Scale is an annual contract with a $1,000 monthly minimum starting on day 61 after the first 60 days with no minimum; it includes every live channel, unlimited domains, and unlimited API keys. A separate limited builder offer gives qualified teams a $100/month lifetime minimum, $600 in onboarding, and 10DLC approval support.

Brand identity

Blocx is the programmable messaging product from Otter Technologies Inc., headquartered in Cheyenne, Wyoming, United States.

Channels

Live today: SMS, MMS, RCS, Email, Telegram.
Voice is not a Blocx channel.

Plans

Pay-as-you-go — self-serve, no minimum spend. SMS $0.0079/segment, email $0.001/email (1 sending domain), 1 API key. Not available for SHAFT and other restricted verticals.
Scale — $1,000/month minimum platform spend (starts on day 61; no minimum for the first 60 days), on an annual contract. Every channel and route type at the published rate card — all rates listed on this site are Scale rates. Signup starts with a call. Required tier for SHAFT and other restricted verticals.
Volume — custom volume-based pricing negotiated on your traffic profile. Contact sales.

Published rate card (+ carrier passthrough on SMS/MMS)

SMS: 10DLC $0.0045, toll-free $0.0055, short code $0.007.
MMS: 10DLC $0.0135, toll-free $0.016, short code $0.018.
RCS: $0.0135/msg + one-time $1,000 setup fee.
Email: $0.0002 per email, flat.
Verify: $0.035 per successful verify, flat.
Telegram: $0.0045/msg, flat.