# Listrak Two-Way SMS API

> REST API for two-way SMS conversations — open and close support tickets, stream conversation messages, and send outbound SMS replies.
> Base URL `https://api.listrak.com/twowaysms`. Auth: OAuth2 client_credentials at `https://auth.listrak.com/OAuth2/Token` (Bearer token).
> This documentation is plain markdown, designed to be fetched and read directly by coding agents.

## Start here
- [Getting started](https://api-docs.tools.listrak.com/twowaysms/guides/getting-started.md): open a ticket, read the stream, send a reply, close the ticket
- [Authentication (OAuth2)](https://api-docs.tools.listrak.com/twowaysms/guides/authentication.md): client_credentials flow; the spec's apiKey declaration is a gateway artifact
- [Errors & retries](https://api-docs.tools.listrak.com/twowaysms/guides/errors.md): per-route status codes, 409 on ticket open, and why POST /send is never retried
- [PII & logging](https://api-docs.tools.listrak.com/twowaysms/guides/pii-logging.md): phoneId is in the URL path; message text is customer content
- [Copy-paste client & recipes](https://api-docs.tools.listrak.com/twowaysms/guides/recipes.md): full Python + TypeScript client, inbound webhook handling, incremental stream reads

## Conversations
- [Ticket](https://api-docs.tools.listrak.com/twowaysms/reference/ticket.md): Open and close two-way SMS support tickets for a subscriber.
- [OutboundMessage](https://api-docs.tools.listrak.com/twowaysms/reference/outbound-message.md): Send an outbound SMS reply within an open ticket.
- [MessageStream](https://api-docs.tools.listrak.com/twowaysms/reference/message-stream.md): Read the conversation history between a subscriber and your agents.

## Optional
- [Full reference (single file)](https://api-docs.tools.listrak.com/twowaysms/llms-full.txt): everything concatenated
- [OpenAPI spec](https://api-docs.tools.listrak.com/twowaysms/openapi.json): machine-readable OpenAPI 3.x