# 9bits Developer Documentation

> REST APIs for SMS, Email, Voice and VAS (two-way SMS) across multiple markets
> and mobile networks.

Base URL: https://api.9bits.net
Auth: `Authorization: Bearer <API_TOKEN>` (Settings → Security in the dashboard)

All sending is asynchronous: a 2xx means "accepted and queued", never
"delivered". Track outcomes via the status endpoint or a webhook.

## OpenAPI specifications

- [SMS OpenAPI 3.1 spec](https://developer.9bits.net/openapi/sms.yaml)
- [EMAIL OpenAPI 3.1 spec](https://developer.9bits.net/openapi/email.yaml)
- [VOICE OpenAPI 3.1 spec](https://developer.9bits.net/openapi/voice.yaml)
- [VAS OpenAPI 3.1 spec](https://developer.9bits.net/openapi/vas.yaml)

## Documentation

- [Email](https://developer.9bits.net/email/): Transactional email with templates, contact lists, suppressions, domain authentication and stats.
- [Domain authentication](https://developer.9bits.net/email/domains/): SPF, DKIM and DMARC — the difference between the inbox and the spam folder.
- [Send an email](https://developer.9bits.net/email/send/): The messages endpoint field by field, with working examples.
- [Authentication](https://developer.9bits.net/guides/authentication/): How to authenticate every request to the 9bits API.
- [Errors](https://developer.9bits.net/guides/errors/): Every error the 9bits API returns, what causes it, and whether retrying will help.
- [Idempotency & retries](https://developer.9bits.net/guides/idempotency/): Retry a send after a timeout without sending — or billing — the same message twice.
- [Phone number format](https://developer.9bits.net/guides/phone-numbers/): How to format MSISDNs so the API accepts them — and why "0803..." fails.
- [Webhooks](https://developer.9bits.net/guides/webhooks/): Receive delivery receipts, inbound messages, and subscription events — and handle them reliably.
- [Quickstart](https://developer.9bits.net/quickstart/): Send your first SMS with the 9bits API in under five minutes.
- [SMS](https://developer.9bits.net/sms/): Send A2P SMS across every major mobile network, with delivery reports and cost estimates.
- [Delivery reports](https://developer.9bits.net/sms/delivery-reports/): Find out which messages actually reached the handset — by polling, or by webhook.
- [Encoding & pricing](https://developer.9bits.net/sms/encoding/): Why one emoji can double your SMS bill, and how to predict cost before you send.
- [Send an SMS](https://developer.9bits.net/sms/send/): The send endpoint field by field, with working examples in six languages.
- [Sender IDs](https://developer.9bits.net/sms/sender-ids/): The name recipients see your SMS from — how to register one and get it approved.
- [VAS & Two-Way SMS](https://developer.9bits.net/vas/): Run shortcode services — receive subscriber messages, reply in-session, and track subscriptions.
- [Receiving messages](https://developer.9bits.net/vas/receiving/): Handle inbound subscriber messages on your shortcode, and reply in-session.
- [Subscription lifecycle](https://developer.9bits.net/vas/subscriptions/): Activation, renewal and deactivation events — and how to reconcile revenue against them.
- [Voice](https://developer.9bits.net/voice/): Deliver a recorded audio message to up to 1,000 phone numbers in one request.
- [Send a voice message](https://developer.9bits.net/voice/send/): Place an outbound voice-message call and receive the result.
- [WhatsApp](https://developer.9bits.net/whatsapp/): Send WhatsApp Business template and session messages to your customers.
- [Send a WhatsApp message](https://developer.9bits.net/whatsapp/send/): Templates, session messages and media headers — field by field.