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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 0.2923 GBP
ALAlbania 0.0936 GBP
DZAlgeria 0.2381 GBP
ASAmerican Samoa 0.0999 GBP
ADAndorra 0.0708 GBP
AOAngola 0.0663 GBP
AIAnguilla 0.1378 GBP
AGAntigua & Barbuda 0.1888 GBP
ARArgentina 0.0770 GBP
AMArmenia 0.1807 GBP
AWAruba 0.1122 GBP
AUAustralia 0.0258 GBP
ATAustria 0.0442 GBP
AZAzerbaijan 0.2643 GBP
BSBahamas 0.0622 GBP
BHBahrain 0.0357 GBP
BDBangladesh 0.3906 GBP
BBBarbados 0.2073 GBP
BYBelarus 0.1499 GBP
BEBelgium 0.0689 GBP
BZBelize 0.1770 GBP
BJBenin 0.1887 GBP
BMBermuda 0.2073 GBP
BTBhutan 0.2657 GBP
BOBolivia 0.1760 GBP
BABosnia & Herzegovina 0.1199 GBP
BWBotswana 0.1116 GBP
BRBrazil 0.0213 GBP
IOBritish Indian Ocean Territory 0.0969 GBP
VGBritish Virgin Islands 0.2073 GBP
BNBrunei 0.0479 GBP
BGBulgaria 0.1169 GBP
BFBurkina Faso 0.1556 GBP
BIBurundi 0.3367 GBP
KHCambodia 0.2551 GBP
CMCameroon 0.2092 GBP
CACanada 0.0179 GBP
CVCape Verde 0.1621 GBP
KYCayman Islands 0.1913 GBP
CFCentral African Republic 0.0740 GBP
TDChad 0.2471 GBP
CLChile 0.0348 GBP
CNChina 0.0202 GBP
COColombia 0.0160 GBP
KMComoros 0.2704 GBP
CGCongo - Brazzaville 0.1658 GBP
CDCongo - Kinshasa 0.2347 GBP
CKCook Islands 0.0963 GBP
CRCosta Rica 0.0234 GBP
HRCroatia 0.1101 GBP
CUCuba 0.0696 GBP
ANCuraçao 0.1020 GBP
CWCuraçao 0.2338 GBP
CYCyprus 0.0824 GBP
CZCzechia 0.0421 GBP
CICôte d’Ivoire 0.2168 GBP
DKDenmark 0.0392 GBP
DJDjibouti 0.0995 GBP
DMDominica 0.1607 GBP
DODominican Republic 0.1025 GBP
ECEcuador 0.2219 GBP
EGEgypt 0.2372 GBP
SVEl Salvador 0.0969 GBP
GQEquatorial Guinea 0.1531 GBP
EREritrea 0.0790 GBP
EEEstonia 0.0399 GBP
SZEswatini 0.1301 GBP
ETEthiopia 0.2338 GBP
FKFalkland Islands 0.0556 GBP
FOFaroe Islands 0.0406 GBP
FJFiji 0.1435 GBP
FIFinland 0.0357 GBP
FRFrance 0.0420 GBP
GFFrench Guiana 0.0456 GBP
PFFrench Polynesia 0.0685 GBP
GAGabon 0.2286 GBP
GMGambia 0.1329 GBP
GEGeorgia 0.1025 GBP
DEGermany 0.0741 GBP
GHGhana 0.1862 GBP
GIGibraltar 0.0543 GBP
GRGreece 0.0371 GBP
GLGreenland 0.0096 GBP
GDGrenada 0.1913 GBP
GPGuadeloupe 0.0944 GBP
GUGuam 0.1046 GBP
GTGuatemala 0.1658 GBP
GNGuinea 0.2041 GBP
GWGuinea-Bissau 0.1888 GBP
GYGuyana 0.2041 GBP
HTHaiti 0.2073 GBP
HNHonduras 0.1122 GBP
HKHong Kong SAR China 0.0477 GBP
HUHungary 0.0553 GBP
ISIceland 0.0537 GBP
INIndia 0.0633 GBP
IDIndonesia 0.3427 GBP
IRIran 0.2908 GBP
IQIraq 0.2860 GBP
IEIreland 0.0357 GBP
ILIsrael 0.1701 GBP
ITItaly 0.0406 GBP
JMJamaica 0.1015 GBP
JPJapan 0.0429 GBP
JOJordan 0.2653 GBP
KZKazakhstan 0.2870 GBP
KEKenya 0.1020 GBP
KIKiribati 0.0433 GBP
XKKosovo 0.2126 GBP
KWKuwait 0.2445 GBP
KGKyrgyzstan 0.2184 GBP
LALaos 0.1071 GBP
LVLatvia 0.0425 GBP
LBLebanon 0.0408 GBP
LSLesotho 0.2015 GBP
LRLiberia 0.1531 GBP
LYLibya 0.2711 GBP
LILiechtenstein 0.0339 GBP
LTLithuania 0.0345 GBP
LULuxembourg 0.0867 GBP
MOMacao SAR China 0.0374 GBP
MGMadagascar 0.3321 GBP
MWMalawi 0.2232 GBP
MYMalaysia 0.1275 GBP
MVMaldives 0.0536 GBP
MLMali 0.1811 GBP
MTMalta 0.0466 GBP
MHMarshall Islands 0.0479 GBP
MQMartinique 0.0425 GBP
MRMauritania 0.1939 GBP
MUMauritius 0.1314 GBP
MXMexico 0.0612 GBP
FMMicronesia 0.0628 GBP
MDMoldova 0.1133 GBP
MCMonaco 0.1117 GBP
MNMongolia 0.2498 GBP
MEMontenegro 0.1223 GBP
MSMontserrat 0.1071 GBP
MAMorocco 0.0612 GBP
MZMozambique 0.1071 GBP
MMMyanmar (Burma) 0.3136 GBP
NANamibia 0.0361 GBP
NRNauru 0.1435 GBP
NPNepal 0.2092 GBP
NLNetherlands 0.0649 GBP
NCNew Caledonia 0.1008 GBP
NZNew Zealand 0.0357 GBP
NINicaragua 0.0995 GBP
NENiger 0.2392 GBP
NGNigeria 0.2857 GBP
NUNiue 0.1382 GBP
KPNorth Korea 0.0713 GBP
MKNorth Macedonia 0.0749 GBP
NONorway 0.0306 GBP
OMOman 0.1488 GBP
PKPakistan 0.3061 GBP
PWPalau 0.0974 GBP
PSPalestinian Territories 0.2514 GBP
PAPanama 0.1250 GBP
PGPapua New Guinea 0.1648 GBP
PYParaguay 0.0714 GBP
PEPeru 0.1071 GBP
PHPhilippines 0.1802 GBP
PLPoland 0.0213 GBP
PTPortugal 0.0224 GBP
PRPuerto Rico 0.0889 GBP
QAQatar 0.0893 GBP
RORomania 0.0394 GBP
RURussia 0.3434 GBP
RWRwanda 0.2365 GBP
RERéunion 0.0536 GBP
WSSamoa 0.1199 GBP
SMSan Marino 0.0476 GBP
SASaudi Arabia 0.1633 GBP
SNSenegal 0.2015 GBP
RSSerbia 0.1658 GBP
SCSeychelles 0.0918 GBP
SLSierra Leone 0.1990 GBP
SGSingapore 0.0392 GBP
SXSint Maarten 0.0796 GBP
SKSlovakia 0.0432 GBP
SISlovenia 0.1329 GBP
SBSolomon Islands 0.0714 GBP
SOSomalia 0.1811 GBP
ZASouth Africa 0.0408 GBP
KRSouth Korea 0.0170 GBP
SSSouth Sudan 0.2232 GBP
ESSpain 0.0315 GBP
LKSri Lanka 0.3184 GBP
SHSt. Helena 0.0798 GBP
KNSt. Kitts & Nevis 0.2073 GBP
LCSt. Lucia 0.2015 GBP
PMSt. Pierre & Miquelon 0.1020 GBP
VCSt. Vincent & Grenadines 0.1607 GBP
SDSudan 0.2605 GBP
SRSuriname 0.1862 GBP
SESweden 0.0412 GBP
CHSwitzerland 0.0505 GBP
SYSyria 0.2503 GBP
STSão Tomé & Príncipe 0.0204 GBP
TWTaiwan 0.0638 GBP
TJTajikistan 0.3068 GBP
TZTanzania 0.2286 GBP
THThailand 0.0149 GBP
TLTimor-Leste 0.1250 GBP
TGTogo 0.1480 GBP
TKTokelau 0.0213 GBP
TOTonga 0.1435 GBP
TTTrinidad & Tobago 0.2015 GBP
TNTunisia 0.2449 GBP
TMTurkmenistan 0.1861 GBP
TCTurks & Caicos Islands 0.1355 GBP
TVTuvalu 0.1329 GBP
TRTürkiye 0.0065 GBP
VIU.S. Virgin Islands 0.0314 GBP
UGUganda 0.2402 GBP
UAUkraine 0.1488 GBP
AEUnited Arab Emirates 0.0776 GBP
GBUnited Kingdom 0.0341 GBP
USUnited States 0.0179 GBP
ZZUnknown Region 0.0702 GBP
UYUruguay 0.0904 GBP
UZUzbekistan 0.3295 GBP
VUVanuatu 0.1403 GBP
VEVenezuela 0.1122 GBP
VNVietnam 0.1887 GBP
WFWallis & Futuna 0.0630 GBP
YEYemen 0.1467 GBP
ZMZambia 0.2227 GBP
ZWZimbabwe 0.1547 GBP