postline

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Channels

Channels are named in the config. The name is what posts reference in channels:; type picks the adapter. You can have two channels of the same type, for example two LinkedIn pages.

channels:
  linkedin:
    type: linkedin
    organization: "111614509"
  founder:
    type: linkedin
    person: "abc123"
    tokenEnv: FOUNDER_LINKEDIN_TOKEN

Every channel accepts maxChars to override its length limit.

LinkedIn

linkedin:
  type: linkedin
  organization: "111614509"   # the number in linkedin.com/company/<id>/admin
  # person: "<member id>"     # post as a member instead
  # version: "202609"         # LinkedIn-Version header (YYYYMM)
  # tokenEnv: LINKEDIN_ACCESS_TOKEN
  # tokenExpires: 2026-12-31  # when the token stops working; doctor warns 14 days ahead

You need a LinkedIn developer app with the Community Management API product for company pages (scope w_organization_social), or "Share on LinkedIn" for a member (w_member_social). Generate a token for an admin of the page and store it as LINKEDIN_ACCESS_TOKEN.

LinkedIn tokens expire (60 days by default) and can't be inspected, so tell postline when yours runs out with tokenExpires:. postline doctor then warns 14 days ahead, and with alerts configured the daemon tells you on its daily check. See health checks and alerts.

LinkedIn retires API versions roughly a year after release; postline doctor warns when the configured version is 10 months old. postline defaults to the September 2026 API (202609). Check LinkedIn's versioning page before each postline release and update version: when migrating deliberately.

Bluesky

bluesky:
  type: bluesky
  # service: https://bsky.social
  # lang: en

Create an app password under Settings > Privacy and security > App passwords. Set BLUESKY_IDENTIFIER (your handle) and BLUESKY_APP_PASSWORD.

Bluesky posts are limited to 300 characters, so most posts need a variants.bluesky. Images must be under 1 MB; if your PNG cards are larger, use card.format: jpeg.

Each post gets a fixed record key built from its id, channel and scheduled time. Before posting, postline checks whether a record with that key already exists, so a retry after a timeout finds the first post instead of creating a second one. If it finds a record with different text (you edited the post after a lost attempt), it stops and asks you to check the account.

Mastodon

mastodon:
  type: mastodon
  instance: https://mastodon.social
  # visibility: public        # public | unlisted | private

Create an application under Preferences > Development with write:statuses and write:media. Store the access token as MASTODON_ACCESS_TOKEN.

Every status carries an Idempotency-Key, so failed attempts are retried normally. Mastodon remembers keys for about an hour; with the default 15 minute schedule and maxAttempts: 3, every retry falls inside that window.

Webhook

instagram:
  type: webhook
  url: https://hooks.zapier.com/hooks/catch/...
  # secretEnv: POSTLINE_WEBHOOK_SECRET

postline POSTs:

{
  "delivery": "post-id::channel",
  "id": "post-id",
  "channel": "instagram",
  "at": "2026-10-27T13:00:00.000Z",
  "topic": "launch",
  "text": "...",
  "image": { "mime": "image/png", "alt": "...", "base64": "..." }
}

Headers: X-Postline-Delivery (stable, use it to de-duplicate) and, when the secret is set, X-Postline-Signature: sha256=<hex HMAC of the raw body>. Any 2xx counts as success. If the response is JSON with id or url, those are recorded.

A 4xx is retried on the next run. A timeout, dropped connection or 5xx is recorded as uncertain and not retried, because your receiver may already have acted on it. Check it, then run postline mark or postline retry.

Use this for networks postline doesn't cover directly (Instagram, Facebook, X, Threads, TikTok) through Zapier, Make or n8n, or to route posts into a Slack approval step.

Files

blog:
  type: files
  dir: ../website/src/content/social
  assetsDir: ../website/public/social
  assetsUrl: /social

Writes <id>.md with title, date, topic, image and imageAlt front matter, plus the image. Useful for mirroring posts onto a static site or keeping an archive.