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SMS Developer API

Transactional messaging, built into your application.

Send alerts, verification messages and customer updates through a documented API designed for real operational workflows.

Built for developers

One clear API for the messages your product needs to send.

Start with a direct integration, then add controls and delivery feedback as the workflow becomes more important.

01

Send with confidence

Submit outbound SMS through a documented API with recipient and message validation before it enters the delivery queue.

02

Estimate before sending

Check the message and destination before committing usage, so your application can make deliberate decisions.

03

Follow asynchronous status

Use callbacks for delivery events and, where needed, HLR lookup results in the systems that need them.

04

Control access

Use API tokens and optional IP restrictions to keep a production integration scoped to the right system.

From request to result

A small API surface with a clear operational lifecycle.

Your application remains in control: validate the destination, estimate usage, submit once and consume delivery events asynchronously.

01 / Authorise

One token per integration.

Keep production systems isolated with revocable credentials and optional source-IP restrictions.

  • Server-side API tokens
  • Optional IP allowlists
  • No credentials in browser code
02 / Estimate

Know the message before sending.

Use the estimate operation to validate recipient and message characteristics before committing the request.

  • Destination validation
  • Message-part awareness
  • Explicit application decision
03 / Queue

Submit without blocking your product.

Accepted messages enter an asynchronous delivery workflow and return a reference your application can retain.

  • Queued processing
  • Stable message reference
  • Transactional workloads
04 / Observe

Bring status back to your system.

Delivery callbacks let your application update its own workflow without repeatedly polling for every message.

  • Webhook callbacks
  • Delivery-state events
  • Audit-friendly processing
05 / Verify

Support identity workflows.

Use SMS for account creation, requested notifications and two-step login challenges with your own expiry and retry policy.

  • Verification codes
  • Operational notifications
  • No unsolicited marketing
06 / Scale

Pay for actual messaging.

The service is usage-based. Destination, route and sender requirements are confirmed before production traffic is enabled.

  • Country-aware routing
  • Sender review where required
  • Transparent usage records

Manage credentials, allowed sources, usage and delivery activity securely from your Silurian workspace.

Good to know. Delivery confirmation and sender behaviour depend on destination country, network and approved sending route. We will help define the appropriate setup before production use.

Developer experience

Integrate SMS into your applications easily.

Send the same authenticated JSON request from your preferred server-side stack. Keep the API token outside browser code and use the estimate operation before sending when price or message length matters.

Open the interactive API reference
curl --request POST 'https://api.silurian.net/sms/v2/send' \
  --user 'YOUR_API_TOKEN:' \
  --header 'Content-Type: application/json' \
  --data '{
    "sender": "YOURBRAND",
    "message": "Your verification code is 123456.",
    "recipients": [{"msisdn": "+34XXXXXXXXX"}]
  }'
Examples use HTTP Basic authentication with the API token as username. The interactive reference also documents header, query-token and short-lived Bearer authentication.

Destination pricing

Know the destination price before your application sends.

Prices below are the current public Silurian rate per SMS part, before VAT. The API estimate operation remains authoritative because message length, destination, route and sender requirements are checked for each request.

DestinationPrice per SMS part
AFAfghanistan 0.2944 GBP
ALAlbania 0.0943 GBP
DZAlgeria 0.2398 GBP
ASAmerican Samoa 0.1006 GBP
ADAndorra 0.0713 GBP
AOAngola 0.0668 GBP
AIAnguilla 0.1387 GBP
AGAntigua & Barbuda 0.1901 GBP
ARArgentina 0.0776 GBP
AMArmenia 0.1820 GBP
AWAruba 0.1130 GBP
AUAustralia 0.0259 GBP
ATAustria 0.0445 GBP
AZAzerbaijan 0.2661 GBP
BSBahamas 0.0626 GBP
BHBahrain 0.0360 GBP
BDBangladesh 0.3934 GBP
BBBarbados 0.2088 GBP
BYBelarus 0.1510 GBP
BEBelgium 0.0694 GBP
BZBelize 0.1782 GBP
BJBenin 0.1900 GBP
BMBermuda 0.2088 GBP
BTBhutan 0.2676 GBP
BOBolivia 0.1773 GBP
BABosnia & Herzegovina 0.1207 GBP
BWBotswana 0.1124 GBP
BRBrazil 0.0215 GBP
IOBritish Indian Ocean Territory 0.0976 GBP
VGBritish Virgin Islands 0.2088 GBP
BNBrunei 0.0482 GBP
BGBulgaria 0.1177 GBP
BFBurkina Faso 0.1567 GBP
BIBurundi 0.3391 GBP
KHCambodia 0.2569 GBP
CMCameroon 0.2107 GBP
CACanada 0.0180 GBP
CVCape Verde 0.1632 GBP
KYCayman Islands 0.1927 GBP
CFCentral African Republic 0.0745 GBP
TDChad 0.2488 GBP
CLChile 0.0350 GBP
CNChina 0.0204 GBP
COColombia 0.0161 GBP
KMComoros 0.2723 GBP
CGCongo - Brazzaville 0.1670 GBP
CDCongo - Kinshasa 0.2363 GBP
CKCook Islands 0.0970 GBP
CRCosta Rica 0.0235 GBP
HRCroatia 0.1109 GBP
CUCuba 0.0701 GBP
ANCuraçao 0.1028 GBP
CWCuraçao 0.2355 GBP
CYCyprus 0.0830 GBP
CZCzechia 0.0424 GBP
CICôte d’Ivoire 0.2184 GBP
DKDenmark 0.0395 GBP
DJDjibouti 0.1002 GBP
DMDominica 0.1618 GBP
DODominican Republic 0.1033 GBP
ECEcuador 0.2235 GBP
EGEgypt 0.2389 GBP
SVEl Salvador 0.0976 GBP
GQEquatorial Guinea 0.1541 GBP
EREritrea 0.0796 GBP
EEEstonia 0.0402 GBP
SZEswatini 0.1310 GBP
ETEthiopia 0.2355 GBP
FKFalkland Islands 0.0560 GBP
FOFaroe Islands 0.0409 GBP
FJFiji 0.1445 GBP
FIFinland 0.0360 GBP
FRFrance 0.0423 GBP
GFFrench Guiana 0.0459 GBP
PFFrench Polynesia 0.0689 GBP
GAGabon 0.2302 GBP
GMGambia 0.1338 GBP
GEGeorgia 0.1033 GBP
DEGermany 0.0746 GBP
GHGhana 0.1875 GBP
GIGibraltar 0.0546 GBP
GRGreece 0.0373 GBP
GLGreenland 0.0097 GBP
GDGrenada 0.1927 GBP
GPGuadeloupe 0.0951 GBP
GUGuam 0.1053 GBP
GTGuatemala 0.1670 GBP
GNGuinea 0.2055 GBP
GWGuinea-Bissau 0.1901 GBP
GYGuyana 0.2055 GBP
HTHaiti 0.2088 GBP
HNHonduras 0.1130 GBP
HKHong Kong SAR China 0.0480 GBP
HUHungary 0.0557 GBP
ISIceland 0.0540 GBP
INIndia 0.0638 GBP
IDIndonesia 0.3451 GBP
IRIran 0.2929 GBP
IQIraq 0.2880 GBP
IEIreland 0.0360 GBP
ILIsrael 0.1713 GBP
ITItaly 0.0409 GBP
JMJamaica 0.1022 GBP
JPJapan 0.0432 GBP
JOJordan 0.2672 GBP
KZKazakhstan 0.2890 GBP
KEKenya 0.1028 GBP
KIKiribati 0.0436 GBP
XKKosovo 0.2141 GBP
KWKuwait 0.2462 GBP
KGKyrgyzstan 0.2200 GBP
LALaos 0.1079 GBP
LVLatvia 0.0428 GBP
LBLebanon 0.0411 GBP
LSLesotho 0.2030 GBP
LRLiberia 0.1541 GBP
LYLibya 0.2730 GBP
LILiechtenstein 0.0342 GBP
LTLithuania 0.0348 GBP
LULuxembourg 0.0873 GBP
MOMacao SAR China 0.0377 GBP
MGMadagascar 0.3345 GBP
MWMalawi 0.2248 GBP
MYMalaysia 0.1284 GBP
MVMaldives 0.0539 GBP
MLMali 0.1824 GBP
MTMalta 0.0469 GBP
MHMarshall Islands 0.0482 GBP
MQMartinique 0.0428 GBP
MRMauritania 0.1952 GBP
MUMauritius 0.1323 GBP
MXMexico 0.0617 GBP
FMMicronesia 0.0632 GBP
MDMoldova 0.1141 GBP
MCMonaco 0.1125 GBP
MNMongolia 0.2516 GBP
MEMontenegro 0.1231 GBP
MSMontserrat 0.1079 GBP
MAMorocco 0.0617 GBP
MZMozambique 0.1079 GBP
MMMyanmar (Burma) 0.3158 GBP
NANamibia 0.0363 GBP
NRNauru 0.1445 GBP
NPNepal 0.2107 GBP
NLNetherlands 0.0653 GBP
NCNew Caledonia 0.1016 GBP
NZNew Zealand 0.0360 GBP
NINicaragua 0.1002 GBP
NENiger 0.2409 GBP
NGNigeria 0.2877 GBP
NUNiue 0.1392 GBP
KPNorth Korea 0.0718 GBP
MKNorth Macedonia 0.0754 GBP
NONorway 0.0308 GBP
OMOman 0.1499 GBP
PKPakistan 0.3083 GBP
PWPalau 0.0980 GBP
PSPalestinian Territories 0.2531 GBP
PAPanama 0.1259 GBP
PGPapua New Guinea 0.1660 GBP
PYParaguay 0.0719 GBP
PEPeru 0.1079 GBP
PHPhilippines 0.1815 GBP
PLPoland 0.0214 GBP
PTPortugal 0.0225 GBP
PRPuerto Rico 0.0895 GBP
QAQatar 0.0899 GBP
RORomania 0.0396 GBP
RURussia 0.3458 GBP
RWRwanda 0.2381 GBP
RERéunion 0.0539 GBP
WSSamoa 0.1207 GBP
SMSan Marino 0.0480 GBP
SASaudi Arabia 0.1644 GBP
SNSenegal 0.2030 GBP
RSSerbia 0.1670 GBP
SCSeychelles 0.0925 GBP
SLSierra Leone 0.2004 GBP
SGSingapore 0.0395 GBP
SXSint Maarten 0.0802 GBP
SKSlovakia 0.0435 GBP
SISlovenia 0.1338 GBP
SBSolomon Islands 0.0719 GBP
SOSomalia 0.1824 GBP
ZASouth Africa 0.0411 GBP
KRSouth Korea 0.0171 GBP
SSSouth Sudan 0.2248 GBP
ESSpain 0.0317 GBP
LKSri Lanka 0.3206 GBP
SHSt. Helena 0.0803 GBP
KNSt. Kitts & Nevis 0.2088 GBP
LCSt. Lucia 0.2030 GBP
PMSt. Pierre & Miquelon 0.1028 GBP
VCSt. Vincent & Grenadines 0.1618 GBP
SDSudan 0.2623 GBP
SRSuriname 0.1875 GBP
SESweden 0.0415 GBP
CHSwitzerland 0.0509 GBP
SYSyria 0.2521 GBP
STSão Tomé & Príncipe 0.0206 GBP
TWTaiwan 0.0642 GBP
TJTajikistan 0.3090 GBP
TZTanzania 0.2302 GBP
THThailand 0.0150 GBP
TLTimor-Leste 0.1259 GBP
TGTogo 0.1490 GBP
TKTokelau 0.0214 GBP
TOTonga 0.1445 GBP
TTTrinidad & Tobago 0.2030 GBP
TNTunisia 0.2466 GBP
TMTurkmenistan 0.1874 GBP
TCTurks & Caicos Islands 0.1365 GBP
TVTuvalu 0.1338 GBP
TRTürkiye 0.0065 GBP
VIU.S. Virgin Islands 0.0316 GBP
UGUganda 0.2419 GBP
UAUkraine 0.1499 GBP
AEUnited Arab Emirates 0.0782 GBP
GBUnited Kingdom 0.0343 GBP
USUnited States 0.0180 GBP
ZZUnknown Region 0.0706 GBP
UYUruguay 0.0910 GBP
UZUzbekistan 0.3318 GBP
VUVanuatu 0.1413 GBP
VEVenezuela 0.1130 GBP
VNVietnam 0.1900 GBP
WFWallis & Futuna 0.0635 GBP
YEYemen 0.1477 GBP
ZMZambia 0.2243 GBP
ZWZimbabwe 0.1558 GBP