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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 0.2945 GBP
ALAlbania 0.0943 GBP
DZAlgeria 0.2398 GBP
ASAmerican Samoa 0.1006 GBP
ADAndorra 0.0714 GBP
AOAngola 0.0668 GBP
AIAnguilla 0.1388 GBP
AGAntigua & Barbuda 0.1902 GBP
ARArgentina 0.0776 GBP
AMArmenia 0.1820 GBP
AWAruba 0.1131 GBP
AUAustralia 0.0260 GBP
ATAustria 0.0445 GBP
AZAzerbaijan 0.2662 GBP
BSBahamas 0.0626 GBP
BHBahrain 0.0360 GBP
BDBangladesh 0.3935 GBP
BBBarbados 0.2088 GBP
BYBelarus 0.1510 GBP
BEBelgium 0.0694 GBP
BZBelize 0.1782 GBP
BJBenin 0.1901 GBP
BMBermuda 0.2088 GBP
BTBhutan 0.2677 GBP
BOBolivia 0.1773 GBP
BABosnia & Herzegovina 0.1208 GBP
BWBotswana 0.1125 GBP
BRBrazil 0.0215 GBP
IOBritish Indian Ocean Territory 0.0976 GBP
VGBritish Virgin Islands 0.2088 GBP
BNBrunei 0.0482 GBP
BGBulgaria 0.1178 GBP
BFBurkina Faso 0.1567 GBP
BIBurundi 0.3392 GBP
KHCambodia 0.2570 GBP
CMCameroon 0.2107 GBP
CACanada 0.0180 GBP
CVCape Verde 0.1633 GBP
KYCayman Islands 0.1927 GBP
CFCentral African Republic 0.0745 GBP
TDChad 0.2489 GBP
CLChile 0.0350 GBP
CNChina 0.0204 GBP
COColombia 0.0161 GBP
KMComoros 0.2724 GBP
CGCongo - Brazzaville 0.1670 GBP
CDCongo - Kinshasa 0.2364 GBP
CKCook Islands 0.0970 GBP
CRCosta Rica 0.0236 GBP
HRCroatia 0.1109 GBP
CUCuba 0.0702 GBP
ANCuraçao 0.1028 GBP
CWCuraçao 0.2356 GBP
CYCyprus 0.0830 GBP
CZCzechia 0.0424 GBP
CICôte d’Ivoire 0.2184 GBP
DKDenmark 0.0395 GBP
DJDjibouti 0.1002 GBP
DMDominica 0.1619 GBP
DODominican Republic 0.1033 GBP
ECEcuador 0.2236 GBP
EGEgypt 0.2390 GBP
SVEl Salvador 0.0976 GBP
GQEquatorial Guinea 0.1542 GBP
EREritrea 0.0796 GBP
EEEstonia 0.0402 GBP
SZEswatini 0.1311 GBP
ETEthiopia 0.2356 GBP
FKFalkland Islands 0.0560 GBP
FOFaroe Islands 0.0409 GBP
FJFiji 0.1446 GBP
FIFinland 0.0360 GBP
FRFrance 0.0423 GBP
GFFrench Guiana 0.0459 GBP
PFFrench Polynesia 0.0690 GBP
GAGabon 0.2302 GBP
GMGambia 0.1339 GBP
GEGeorgia 0.1033 GBP
DEGermany 0.0746 GBP
GHGhana 0.1876 GBP
GIGibraltar 0.0546 GBP
GRGreece 0.0373 GBP
GLGreenland 0.0097 GBP
GDGrenada 0.1927 GBP
GPGuadeloupe 0.0951 GBP
GUGuam 0.1054 GBP
GTGuatemala 0.1670 GBP
GNGuinea 0.2056 GBP
GWGuinea-Bissau 0.1902 GBP
GYGuyana 0.2056 GBP
HTHaiti 0.2088 GBP
HNHonduras 0.1131 GBP
HKHong Kong SAR China 0.0481 GBP
HUHungary 0.0557 GBP
ISIceland 0.0540 GBP
INIndia 0.0638 GBP
IDIndonesia 0.3452 GBP
IRIran 0.2929 GBP
IQIraq 0.2881 GBP
IEIreland 0.0360 GBP
ILIsrael 0.1713 GBP
ITItaly 0.0409 GBP
JMJamaica 0.1023 GBP
JPJapan 0.0433 GBP
JOJordan 0.2672 GBP
KZKazakhstan 0.2891 GBP
KEKenya 0.1028 GBP
KIKiribati 0.0436 GBP
XKKosovo 0.2141 GBP
KWKuwait 0.2463 GBP
KGKyrgyzstan 0.2200 GBP
LALaos 0.1079 GBP
LVLatvia 0.0428 GBP
LBLebanon 0.0411 GBP
LSLesotho 0.2030 GBP
LRLiberia 0.1542 GBP
LYLibya 0.2731 GBP
LILiechtenstein 0.0342 GBP
LTLithuania 0.0348 GBP
LULuxembourg 0.0874 GBP
MOMacao SAR China 0.0377 GBP
MGMadagascar 0.3346 GBP
MWMalawi 0.2248 GBP
MYMalaysia 0.1285 GBP
MVMaldives 0.0540 GBP
MLMali 0.1824 GBP
MTMalta 0.0469 GBP
MHMarshall Islands 0.0482 GBP
MQMartinique 0.0428 GBP
MRMauritania 0.1953 GBP
MUMauritius 0.1323 GBP
MXMexico 0.0617 GBP
FMMicronesia 0.0632 GBP
MDMoldova 0.1142 GBP
MCMonaco 0.1126 GBP
MNMongolia 0.2517 GBP
MEMontenegro 0.1232 GBP
MSMontserrat 0.1079 GBP
MAMorocco 0.0617 GBP
MZMozambique 0.1079 GBP
MMMyanmar (Burma) 0.3159 GBP
NANamibia 0.0363 GBP
NRNauru 0.1446 GBP
NPNepal 0.2107 GBP
NLNetherlands 0.0654 GBP
NCNew Caledonia 0.1016 GBP
NZNew Zealand 0.0360 GBP
NINicaragua 0.1002 GBP
NENiger 0.2409 GBP
NGNigeria 0.2878 GBP
NUNiue 0.1392 GBP
KPNorth Korea 0.0719 GBP
MKNorth Macedonia 0.0755 GBP
NONorway 0.0308 GBP
OMOman 0.1499 GBP
PKPakistan 0.3084 GBP
PWPalau 0.0981 GBP
PSPalestinian Territories 0.2532 GBP
PAPanama 0.1259 GBP
PGPapua New Guinea 0.1660 GBP
PYParaguay 0.0720 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 0.0397 GBP
RURussia 0.3459 GBP
RWRwanda 0.2382 GBP
RERéunion 0.0540 GBP
WSSamoa 0.1208 GBP
SMSan Marino 0.0480 GBP
SASaudi Arabia 0.1645 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 0.1339 GBP
SBSolomon Islands 0.0720 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 0.3207 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 0.1619 GBP
SDSudan 0.2624 GBP
SRSuriname 0.1876 GBP
SESweden 0.0415 GBP
CHSwitzerland 0.0509 GBP
SYSyria 0.2522 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 0.1446 GBP
TTTrinidad & Tobago 0.2030 GBP
TNTunisia 0.2467 GBP
TMTurkmenistan 0.1874 GBP
TCTurks & Caicos Islands 0.1365 GBP
TVTuvalu 0.1339 GBP
TRTürkiye 0.0065 GBP
VIU.S. Virgin Islands 0.0316 GBP
UGUganda 0.2420 GBP
UAUkraine 0.1499 GBP
AEUnited Arab Emirates 0.0782 GBP
GBUnited Kingdom 0.0343 GBP
USUnited States 0.0180 GBP
ZZUnknown Region 0.0707 GBP
UYUruguay 0.0911 GBP
UZUzbekistan 0.3319 GBP
VUVanuatu 0.1413 GBP
VEVenezuela 0.1131 GBP
VNVietnam 0.1901 GBP
WFWallis & Futuna 0.0635 GBP
YEYemen 0.1478 GBP
ZMZambia 0.2243 GBP
ZWZimbabwe 0.1558 GBP