Developer-first

One API in front of every provider.

Order, poll, release — that is the whole surface for most integrations. Plain HTTPS and JSON, bearer auth, no client library required and no proprietary protocol to learn.

Read the documentation Quickstart

The whole flow, in two calls

# Order a US number for WhatsApp
curl -s https://smsmetro.com/api/v1/activations \
  -H "Authorization: Bearer $SMSMETRO_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{"service":"whatsapp","country":"US"}'

# Poll until the code lands
curl -s https://smsmetro.com/api/v1/activations/ACT_ID \
  -H "Authorization: Bearer $SMSMETRO_KEY"

Or skip polling entirely and take a signed webhook the moment the message arrives.

What the API gives you

Smart or manual routing

Let routing pick the source — balanced, cheapest, fastest or best quality per request — or list every offer for a country and service and buy a specific one.

Signed webhooks

Deliveries carry an HMAC-SHA256 signature over a timestamp and the raw body, so you can verify authenticity and reject replays.

Idempotent purchases

Every purchase takes an Idempotency-Key, claimed in the database before the request runs. A retry after a timeout cannot buy twice.

Scoped keys

Keys carry only the scopes they need — catalogue, read, write, wallet, stats — so a leaked read key cannot spend money.

Wallet-backed billing

Prices are held, then captured or released. Balances derive from a double-entry ledger the database itself refuses to let drift.

Honest status data

Availability is a band, prices are integers in micro-units, and success rates are suppressed until the sample is large enough to mean anything.

Endpoints

EndpointPurpose
GET /v1/countries Countries with routable inventory
GET /v1/services The service catalogue
GET /v1/prices Cheapest price per service
GET /v1/offers Every purchasable source for a country and service
POST /v1/activations Buy a number — smart or manual
GET /v1/activations/{id} State, number, price, expiry
GET /v1/activations/{id}/sms Messages received, code extracted
POST /v1/activations/{id}/cancel Release a number early
GET /v1/balance Wallet balance

Full parameters, response shapes and every error code are in the API documentation.

Where we are honest with you

The API is v1-beta. Breaking changes are announced in advance but remain permitted until three external integrations have sustained thirty days of real traffic. Official SDKs are planned and not yet published — the surface is small enough that plain HTTP is a first-class path, and we would rather ship no SDK than an unmaintained one.

Get an API key in two minutes.

Create an account, generate a scoped key, and make your first call against real inventory.

Create an account Read the API docs