> ## Documentation Index
> Fetch the complete documentation index at: https://docs.poly.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Number availability & compliance
> Country-by-country Twilio number availability, throughput limits, lead times, and regulatory links for 2-way SMS.
2-way SMS lets your PolyAI agent both send **and** receive text messages in a conversation — the caller can reply to an SMS and the agent continues the dialogue over text. This is different from outbound-only SMS (confirmations, links, follow-ups) where no reply is expected.
Not every country supports 2-way SMS, and the type of phone number you use affects throughput, cost, and lead time. This page helps you plan which countries you can cover, which number type to choose, and what compliance steps to complete before launch.
PolyAI uses [Twilio](https://www.twilio.com/) as the underlying SMS provider. The availability data, throughput figures, and regulation links below come from Twilio's published guidelines.
## Number types
There are two main types of SMS-capable phone number. Choosing between them depends on your expected message volume and how quickly you need to go live.
**MPS** (messages per second) is the maximum rate at which a number can send SMS. Higher MPS means you can handle more concurrent conversations without queuing delays.
| Type | Best for | Throughput (MPS) | Typical lead time |
| -------------------------------------------- | ---------------------------------------------------------------------------------------- | --------------------------- | -------------------------------------- |
| **Short code** (5–6 digits) | High-volume transactional messaging. Highest throughput and best carrier deliverability. | 1,000–3,000 (US/CA) | 6–16 weeks (carrier approval required) |
| **Long code** (standard phone number format) | Conversational 2-way SMS, moderate volume. | 10–225 depending on country | Immediate to several weeks |
For US and Canada, long codes are capped at **225 MPS total** across AT\&T, T-Mobile, and Verizon (75 MPS per carrier). If you need higher throughput, apply for a short code — but factor in the 6–10 week approval timeline.
## Availability by country
"Private Offering" means the number type is available but requires a direct arrangement with Twilio — contact your Twilio account manager to set it up.
### North America
| Country | 2-way SMS | Short code | SC MPS | SC lead time | Long code | LC MPS | LC lead time | Regulations |
| ------------- | --------- | ---------- | ----------- | ------------ | --------- | -------------------------- | ------------ | ------------------------------------------------------------------- |
| United States | Yes | Available | 1,000–3,000 | 6–10 weeks | Available | 225 (75 per major carrier) | Immediate | [US SMS guidelines](https://www.twilio.com/en-us/guidelines/us/sms) |
| Canada | Yes | Available | 1,000–3,000 | 6–10 weeks | Available | 225 (75 per major carrier) | Immediate | [CA SMS guidelines](https://www.twilio.com/en-us/guidelines/ca/sms) |
### Europe — 2-way SMS supported
| Country | Short code | SC MPS | SC lead time | Long code | LC MPS | LC lead time | Regulations |
| -------------- | ------------- | ------ | ---------------- | --------- | ------ | ---------------- | --------------------------------------------------------------- |
| United Kingdom | Available | 300+ | 10–16 weeks | Available | 10 | Immediate | [UK guidelines](https://www.twilio.com/en-us/guidelines/gb/sms) |
| Germany | Available | — | Private Offering | Available | 10 | Immediate | [DE guidelines](https://www.twilio.com/en-us/guidelines/de/sms) |
| France | Available | — | Private Offering | Available | 10 | Private Offering | [FR guidelines](https://www.twilio.com/en-us/guidelines/fr/sms) |
| Ireland | Not available | — | — | Available | 10 | — | [IE guidelines](https://www.twilio.com/en-us/guidelines/ie/sms) |
| Netherlands | Not available | — | — | Available | 10 | Immediate | [NL guidelines](https://www.twilio.com/en-us/guidelines/nl/sms) |
| Italy | Not available | — | — | Available | 10 | Private Offering | [IT guidelines](https://www.twilio.com/en-us/guidelines/it/sms) |
| Czech Republic | Not available | — | — | Available | 10 | Immediate | [CZ guidelines](https://www.twilio.com/en-us/guidelines/cz/sms) |
### Europe — 2-way SMS not supported
These countries do not currently support 2-way SMS through Twilio. Neither short codes nor long codes are available for bidirectional messaging.
| Country | Regulations |
| -------- | --------------------------------------------------------------- |
| Croatia | [HR guidelines](https://www.twilio.com/en-us/guidelines/hr/sms) |
| Bulgaria | [BG guidelines](https://www.twilio.com/en-us/guidelines/bg/sms) |
| Slovakia | [SK guidelines](https://www.twilio.com/en-us/guidelines/sk/sms) |
## Compliance requirements
Carrier regulations vary by country and must be met **before** you send any messages. Non-compliance can result in messages being silently dropped or your number being suspended.
### US and Canada — A2P 10DLC
US and Canadian long code SMS requires [A2P 10DLC registration](/voice-channel/message-templates#a2p-10dlc-registration-us-and-canada). Without it, carriers block messages entirely. See the [SMS overview](/voice-channel/message-templates) for the full registration walkthrough.
For short code campaigns:
* **US**: Follow the [CTIA Short Code Monitoring Handbook](https://api.ctia.org/wp-content/uploads/2024/01/CTIA-Short-Code-Monitoring-Handbook-v1.9-FINAL.pdf) and [Messaging Principles and Best Practices](https://api.ctia.org/wp-content/uploads/2023/05/230523-CTIA-Messaging-Principles-and-Best-Practices-FINAL.pdf).
* **Canada**: Follow the [Canadian Wireless Telecommunications Association (txt.ca)](https://txt.ca/) guidelines.
* Both US and CA short code applications require a screenshot or mock-up of the opt-in process.
### United Kingdom
* Follow the [UK Mobile Network Operator Code of Practice](https://www.twilio.com/en-us/guidelines/gb/sms).
* Short code provisioning takes **10–16 weeks** and goes through a separate carrier approval process.
* Long codes are available immediately through the Twilio Console.
### EU countries
Each EU country has its own regulatory framework — check the regulation links in the tables above. Key considerations:
* Some countries (France, Italy) require a **Private Offering** arrangement with Twilio for number provisioning.
* GDPR applies to all EU SMS communications — ensure you have appropriate consent and opt-out mechanisms.
## Pre-launch checklist
Before going live with 2-way SMS in any country:
1. **Confirm number availability** — check the tables above to verify your target country supports 2-way SMS and that the number type you need is available.
2. **Provision your number** — long codes can often be provisioned immediately through the Twilio Console; short codes require a carrier application.
3. **Complete registration** — for US/CA, complete [A2P 10DLC registration](/voice-channel/message-templates#a2p-10dlc-registration-us-and-canada). For other countries, follow the linked regulatory guidelines.
4. **Validate your campaign** — use the [A2P Campaign Pre-Scanner](https://www.a2pcheck.com/) to check your setup against carrier requirements before sending.
5. **Connect to PolyAI** — follow the [SMS setup guide](/voice-channel/message-templates#connect-your-twilio-account) to link your Twilio number to your PolyAI project.
## Industry resources
### Regulatory bodies
* [CTIA — The Wireless Association](https://www.ctia.org/the-wireless-industry/industry-commitments/messaging-interoperability-sms-mms) — US industry body governing short code campaigns and A2P messaging standards.
* [Canadian Wireless Telecommunications Association (CWTA / txt.ca)](https://txt.ca/) — Canadian equivalent; governs short code applications and carrier compliance.
* [Ofcom — Premium Rate Services](https://www.ofcom.org.uk/make-a-complaint/complain-about-premium-rate-services/quick-guide-to-premium-rate-services-prs) — UK regulator for premium-rate and short code services (took over from the PSA in 2025).
* [BEREC — Body of European Regulators for Electronic Communications](https://www.berec.europa.eu/) — EU-wide telecom regulatory coordination.
### Twilio documentation
* [Twilio Messaging Guidelines by Country](https://www.twilio.com/en-us/guidelines) — per-country SMS regulations, sender types, and carrier requirements.
* [A2P 10DLC Overview](https://www.twilio.com/docs/messaging/compliance/a2p-10dlc) — registration walkthrough for US and Canadian long code SMS.
* [Twilio Short Code Guide](https://www.twilio.com/docs/numbers-and-senders/short-codes) — how short codes work, provisioning, and compliance requirements.
* [Twilio Short Code Provisioning in Console](https://help.twilio.com/articles/30888460607003) — step-by-step application walkthrough.
* [Twilio Messaging Services](https://www.twilio.com/docs/messaging/services) — number pooling, compliance, and scaling for high-volume use cases.
* [Twilio Phone Number Regulatory Compliance](https://www.twilio.com/docs/phone-numbers/regulatory/getting-started) — identity and address verification requirements by country.
### Carrier compliance
* [CTIA Short Code Monitoring Handbook (v1.9, PDF)](https://api.ctia.org/wp-content/uploads/2024/01/CTIA-Short-Code-Monitoring-Handbook-v1.9-FINAL.pdf) — rules for US short code campaigns.
* [CTIA Messaging Principles and Best Practices (May 2023, PDF)](https://api.ctia.org/wp-content/uploads/2023/05/230523-CTIA-Messaging-Principles-and-Best-Practices-FINAL.pdf) — US carrier expectations for A2P messaging content and opt-in.
* [UK Code of Practice for Common Short Codes](https://www.short-codes.com/short-code-uk/uk-code-of-practice/) — UK MNO requirements for short code services.
### Compliance tools
* [A2P Campaign Pre-Scanner](https://www.a2pcheck.com/) — validate your campaign setup against carrier requirements before launch.
* [Twilio Trust Hub](https://www.twilio.com/docs/trust-hub) — manage brand and campaign registrations for A2P compliance.
## Related pages
Set up Twilio, create templates, and send SMS from your agent.
Send SMS programmatically and open reply-enabled sessions.
Connect your Twilio account for voice and SMS.
Purchase PolyAI-provisioned numbers for voice.