> ## Documentation Index > Fetch the complete documentation index at: https://docs.social-api.ai/llms.txt > Use this file to discover all available pages before exploring further. # Core concepts > The five nouns SocialAPI's API exposes (Brand, Account, Post, Interaction, Capability) and how they fit together. SocialAPI.ai is a unified social media API: one REST endpoint and MCP server to read and respond to comments, direct messages, mentions, and reviews across Instagram, Facebook, TikTok, LinkedIn, YouTube, X, Threads, WhatsApp, Telegram, Google Business Profile, and Pinterest. Every platform returns the same `Interaction` schema. SocialAPI's REST API is shaped around five nouns. Once you know what each one means, every endpoint slots into place: brands group accounts, accounts hold posts and interactions, and capabilities tell you which actions are valid for any given interaction. This page is a short tour. The [API Reference](/api-reference/introduction) has the exhaustive field-by-field schema for each one. ## Brand A **Brand** (called a *social profile* in pricing) is the top-level grouping in SocialAPI. One brand corresponds to one business, client, or location. All connected social accounts, posts, and interactions live under a brand. Brands matter for two reasons: 1. **Billing.** Plans are sized in social profiles (brands). Free includes 2, Starter 10, Pro 50, Business 200, Enterprise unlimited. 2. **Isolation.** Accounts under one brand cannot see accounts under another. Use brands to keep agency clients separated, or to split staging from production. ```json theme={null} { "id": "3fa85f64-5717-4562-b3fc-2c963f66afa6", "name": "Acme Corp", "created_at": "2026-04-12T09:30:00Z" } ``` See [`/v1/brands`](/api-reference/introduction) for the full schema and CRUD endpoints. Treat IDs as opaque strings. Brands, posts, and invites are UUIDs; accounts are prefixed with `acc_`. Do not parse them or assume a format, and store them as text. See [IDs are opaque strings](/guides/reliability#ids-are-opaque-strings). Brand creation is not idempotent: there is no `external_id` or idempotency key, and brand names are not unique, so a retried `POST /v1/brands` creates a duplicate. Persist the returned brand ID immediately, and check for an existing brand before creating another. ## Account An **Account** is a connected social account under a brand. One brand can hold many accounts, across any mix of platforms. SocialAPI stores the OAuth tokens (encrypted at rest) and refreshes them automatically. You connect an account by calling `POST /v1/accounts/connect` and walking the user through OAuth. After connection, the account ID (prefixed `acc_`) is what you pass to every account-scoped endpoint. ```json theme={null} { "id": "acc_01HZ9X3Q4R5M6N7P8V2K0W1J", "platform": "instagram", "name": "Acme Corp", "username": "acmecorp", "profile_picture_url": "https://scontent.cdninstagram.com/v/...", "bio": "Sustainable apparel. Shipping worldwide." } ``` The full Account schema, including the per-platform `metadata` object, is documented in [Connectors overview](/connectors/overview#account-object). See also: [Authentication](/guides/authentication), [OAuth](/guides/oauth). ## Post A **Post** is one piece of outbound content. A post can target multiple accounts at publishing time, so a single `POST /v1/posts` call can fan out to Instagram, Facebook, and Threads in one shot. Internally a post has two parts: the post itself (text, media, scheduled time) and a per-platform delivery row that tracks status, errors, and engagement metrics for each target. That split is what lets a single post object report "published on Instagram, failed on Facebook" cleanly. ```json theme={null} { "id": "7c9e6679-7425-40de-944b-e07fc1f90ae7", "text": "Spring collection is live.", "status": "published", "scheduled_at": null, "targets": [ { "account_id": "acc_01HZ9X3Q4R5M6N7P8V2K0W1J", "platform": "instagram", "status": "published", "platform_post_id": "17895695668004550", "permalink": "https://www.instagram.com/p/ABC123/", "metrics": { "like_count": 42, "comments_count": 5 } } ], "created_at": "2026-04-15T11:00:00Z" } ``` Posts move through a state machine: `draft`, `scheduled`, `publishing`, then `published` (or `partial`, `failed`). See the [Posts tab](/posts/overview) for per-platform field references. ## Interaction An **Interaction** is anything inbound: a comment on one of your posts, a DM, a review, or a mention. Comments, reviews, and mentions are proxied live from the platform; DM conversations and messages are stored in SocialAPI's database to support threading and pagination. The API mints stable IDs so your app can reference any interaction across calls. Interaction IDs encode their type as a prefix: | Prefix | Type | | ----------- | ------- | | `sapi_cmt_` | Comment | | `sapi_dm_` | DM | | `sapi_rev_` | Review | | `sapi_mnt_` | Mention | ```json theme={null} { "id": "sapi_cmt_GXRM4BNTW7KFYSD3HAEV6QJZ2CLP9U", "platform": "instagram", "type": "comment", "author": { "id": "17841405793187218", "name": "Jane Smith" }, "content": { "text": "Love this product!" }, "created_at": "2026-04-15T14:30:00Z", "capabilities": { "can_reply": true, "can_delete": true, "can_hide": true, "can_like": false, "can_private_reply": true } } ``` The prefix lets the API dispatch a reply without a database lookup. See [Interaction IDs](/guides/interaction-ids) for the encoding details. ## Capability A **Capability** is a per-platform per-feature flag returned on every interaction so your code knows which actions are valid right now. Instead of branching on platform names ("if instagram, can like; if linkedin, can not"), you read the `capabilities` object on the interaction and disable UI controls accordingly. ```json theme={null} { "capabilities": { "can_reply": true, "can_delete": true, "can_hide": true, "can_like": false, "can_private_reply": true } } ``` If you call an action whose flag is `false`, the API returns `501` with `error.code: "resource.not_supported"`. Treat 501 as a permanent platform limitation, not a bug. See [Platform support](/guides/platforms) for the full per-platform breakdown.