Marc
10 July 2025 · 1 min read
To guarantee a reliable service, we made a choice right from the start of the project: use real GSM lines with French carriers, instead of relying on a wholesale SMS API.
Why?
Wholesale SMS APIs (SMTP/HTTP gateways) are convenient but come with several limitations:
- Sender numbers are shared: another customer can get the gateway blacklisted.
- Carriers' anti-spam filters are stricter for these flows.
- Costs climb quickly and are incompatible with a free service.
Our choice: direct GSM
We run our own 3G/4G GSM modems with Orange, SFR and Bouygues SIM cards. Every message literally goes out as if from an ordinary phone:
- Excellent deliverability to all three networks.
- No middleman between us and the carrier.
- Smart routing: if a SIM reaches its quota, the message switches to another one.
Which carriers are supported?
All French carriers are supported on the receiving end:
- Orange / Sosh
- SFR / RED
- Bouygues / B&You
- Free Mobile
- And every MVNO (Lebara, La Poste Mobile, Prixtel, Coriolis…)
The number simply has to start with 06 or 07 and contain 10 digits.
#Carriers#Infrastructure#GSM
