Automate social publishing from n8n with the posterly API

Why n8n and posterly fit together

There is no posterly community node yet, but n8n's HTTP Request node makes that a non-issue: the posterly REST API is a clean JSON API with Bearer auth, exactly what the node is built for. Everything below works the same on n8n Cloud and on a self-hosted instance.

Set up credentials

Generate an API key in your posterly dashboard under Settings, in the API section. API access starts at $3/month on individual plans, with Agency API at $29/month. In n8n, store it as a Header Auth credential with the name Authorization and the value Bearer YOUR_API_KEY, so every node in the workflow reuses it.

Create and schedule posts

Drop in an HTTP Request node, set the method to POST and the URL to https://www.poster.ly/api/v1/posts. In the JSON body, pass caption for the post text, account_id for the target account (fetch your ids once with GET /api/v1/accounts), and an optional scheduled_at ISO timestamp. Leave it off to publish right away. One request targets one account, which fits n8n naturally: feed the node a list of account items and it runs once per account. The response includes the post ID so downstream nodes can track it.

Attach media

Include image or video URLs in the request and posterly fetches, validates, and transcodes them per platform. If your workflow generates images (an AI node, a chart renderer), upload them somewhere reachable first, object storage or a public bucket, then pass the URL.

React to publish events

Add a Webhook node to a new workflow and copy its production URL. Then register it with posterly by calling POST https://www.poster.ly/api/v1/webhooks, subscribing to events like post.published and post.failed. From there your workflow branches however you like: write the live post URL to Postgres, notify a Matrix or Slack channel on failures, or kick off engagement tracking.

Verify signatures in a Code node

posterly signs every webhook delivery with an HMAC SHA-256 signature in the X-posterly-Signature header. In a Code node, recompute the digest from the raw body and your webhook secret with Node's crypto module and compare. On self-hosted instances exposed to the internet, treat this as required rather than optional.

Batch and loop patterns

n8n's Split In Batches node pairs well with the API: read 30 rows from a content calendar in Airtable or Postgres, loop them through one HTTP Request node, and stagger scheduled_at values across the month. Keep the create-post rate under 100 requests per hour, a single Wait node inside the loop handles that.

Roadmap honesty

A dedicated n8n community node is on the posterly roadmap. The HTTP approach is not a workaround in the meantime, it is the same public API surface our MCP server and CLI are built on, and it will remain fully supported.