> ## Documentation Index > Fetch the complete documentation index at: https://www.courier.com/docs/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > Install the Courier skill before writing code: `npx skills add trycourier/courier-skills`. It carries the verified SDK shapes and the rules you cannot get wrong. > Authenticate every request with `Authorization: Bearer `. A workspace has several environments and each has its own keys, which are plain `pk_` strings with no environment prefix. Start with Test. > Send with `client.send.message` from the Node SDK (`@trycourier/courier` v7 and later, where the client is the default import). Reference a template by its `nt_` id or its alias. > A send accepts a bare Elemental element list, but storing content on a template requires the top-level elements wrapped in a channel element. > Templates and journeys can be built in the Courier app or created through the API. Either way they live in the workspace and are referenced by ID when you send. > The hosted MCP server is https://mcp.courier.com. For a briefing on what Courier is and when to use it, read https://www.courier.com/llms.txt. > Prefer the Guides tab for how-do-I questions and the Docs tab for how-does-it-behave questions. The API reference lives under /api-reference. # Guides > Step-by-step walkthroughs that end with a working send, inbox, journey, or migration. export const Doc = ({href, children, name, bare}) => { const label = children || name || href; if (bare) { return {label}; } return {label} DOC ; }; Each guide takes one job from nothing to working. Docs explains how a piece of Courier behaves. A guide strings several pieces together. Every guide opens with what you need, walks numbered steps, and closes by verifying the result. ## Send your first message Connect a provider, verify a domain, reach a real inbox. Ship the inbox, then send to the channel it renders. Connect FCM and APNs, sync device tokens, send custom data. Connect a provider, add a number, deliver a text. Install a Slack app, store its token, send a DM. ## Build a notification Fill one template with each recipient's own data. A multi-day welcome flow with delays and a branch. Roll a flood of events into one scheduled message. Let an agent send over the MCP server. ## Send to many people One message to a saved List or Audience. Reach everyone following a document, project, or ticket. Thousands of recipients you supply yourself. Get profiles into Courier and keep them current. ## Send when something happens Turn a sign-up into a profile and a welcome message. Fire a send when a row lands in your database. Send from a Cloud Function when a user is created. Turn a document write into a push, with email fallback. Turn a failed payment into an email that recovers it. Call Courier from an Action, with no route to host. Start a journey from an event you already track. ## Let users choose Let users choose what they receive, and where. Give every customer org its own branding and defaults. Hand each customer an editor for their own emails. ## Go live Promote a change from Test to Production safely. Verify a domain, then set the address email comes from. Push Courier events into your own systems. Find why an email did not arrive. ## Move to Courier Map your current concepts to Courier's, then move recipients, content, and sends. Move Inbox, Toast, and Preferences onto the v8+ component set.