Allo lets you send and receive SMS directly from your business number. Text prospects back after a missed call, follow up after a meeting, or send appointment reminders.Documentation Index
Fetch the complete documentation index at: https://help.withallo.com/llms.txt
Use this file to discover all available pages before exploring further.
SMS sending requires the Business plan. Starter users can receive SMS only.
What you can do
Get started
Before you can send SMS, you need to complete a one-time registration. The process depends on your number’s country.- US & Canada (10DLC)
- France (Sender ID)
US and Canadian carriers require 10DLC registration before you can send any SMS. Without it, your messages are blocked.Once approved, the SMS composer appears in your Allo inbox and you can start sending immediately.
Approval takes 3 to 7 business days. Start early so you don’t hit any delays.
I'm not based in the US. Do I still need to register?
I'm not based in the US. Do I still need to register?
Yes. 10DLC registration is required for any US number, no matter where you’re located.
I'm porting a number that already has 10DLC. Do I need to re-register?
I'm porting a number that already has 10DLC. Do I need to re-register?
Yes. 10DLC registrations don’t transfer between providers. You’ll need to re-register your brand with Allo.
Automatic SMS replies
Never lose a lead to a missed call. Allo sends a text message automatically when you don’t answer, so your caller knows you’ll get back to them.
- One for missed calls during business hours (“Thanks for calling, I’ll get back to you within the hour”)
- One for calls outside business hours (“Our office is closed, we’ll call you back tomorrow morning”)
US / Canada numbers: Requires 10DLC registration. See the US & Canada (10DLC) tab above.French numbers: Requires a registered Sender ID. See the France (Sender ID) tab above.
Sending limits
| Period | France | US / Canada |
|---|---|---|
| During trial | SMS sending disabled | SMS sending disabled |
| After trial | 40 SMS / day | 150 SMS / day |
Segment-based limits (US/CA)
Your daily limit is counted in segments, not characters. A 161-character message = 2 segments, not 1.| Message type | Characters per segment |
|---|---|
| Plain text (GSM-7) | 160 |
| Unicode (emojis, symbols) | 70 |
For SMS sent via API, separate usage limits apply. See our API reference.
French SMS compliance
Sending business SMS in France requires following ARCEP (telecom), CNIL (data protection), and AF2M (industry charter) rules.Consent rules
Consent rules
B2C (consumer) SMS: Explicit opt-in consent required before sending. Pre-checked boxes are illegal.B2B (professional) SMS: No prior opt-in required, but the message must relate to the recipient’s professional activity. You must identify yourself and offer opt-out.
Time restrictions (marketing SMS only)
Time restrictions (marketing SMS only)
- No marketing SMS on Sundays or French public holidays
- No marketing SMS between 20:00 and 08:00
- Transactional SMS (order confirmations, alerts) has no time restrictions
STOP mechanism
STOP mechanism
Every marketing SMS must include opt-out instructions. With an Alphanumeric Sender ID, include a short code reference in the message body (e.g., “STOP au 36179”).
FAQ
Do I need to register each number separately?
Do I need to register each number separately?
No. 10DLC (US/CA) is a one-time $24 fee for your entire company. Sender ID (France) covers all your French numbers once approved.
Why can't I send MMS with my French number?
Why can't I send MMS with my French number?
MMS is not available for French numbers due to provider limitations. You can send and receive standard SMS text messages.
Can my client reply to an SMS sent with a Sender ID?
Can my client reply to an SMS sent with a Sender ID?
No. SMS sent via Sender ID are one-way: your client sees your company name, but cannot reply directly.
Can I receive SMS on the Starter plan?
Can I receive SMS on the Starter plan?
Yes. Starter users can receive SMS. Sending requires the Business plan.
Do automatic replies work on mobile?
Do automatic replies work on mobile?
Yes. Once configured, automatic SMS replies work regardless of which device you’re using.
Do I need consent to text business contacts in France?
Do I need consent to text business contacts in France?
For B2B contacts, no prior opt-in is required. The message must relate to their professional activity, identify you as the sender, and include opt-out instructions.
I'm porting a number that already has 10DLC. Do I need to re-register?
I'm porting a number that already has 10DLC. Do I need to re-register?
Yes. 10DLC registrations don’t transfer between providers. You’ll need to re-register your brand with Allo and create a new campaign.
Need help?
Contact support
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SMS via API (France)
Developer guide for sending SMS in France via API