postwire

PostWire

Publish one idea to many social networks, with a different post written for each one.

Accounts are connected once through OAuth in the PostWire dashboard, so there is no per-platform developer app, review queue, or token refresh to maintain. One API key covers every network.

When to Use This Skill

The user wants the same idea published to several networks, but written properly for each
The user wants a post scheduled for later, or a week of posts queued from one topic
The user asks why a post failed, or whether a post will fail before sending it
The user is publishing video to TikTok or YouTube from an automation

What Makes This Different

Most multi-posting APIs take one string and send it to every platform. That reads badly and gets suppressed: a LinkedIn post written like a tweet performs like neither. PostWire has a /api/generate step that writes a caption per network — length, tone, hashtags and link handling — from a single prompt, which you then pass to publish or schedule.

It also refuses posts that are going to fail, before they are queued rather than after the platform rejects them:

network	requires
TikTok, YouTube	a video (`video_url`)
Instagram	a photo or a video
everything else	text is enough

Prerequisites

An account at postwire.io — free tier: 1 brand, 30 posts/month, no card
Networks connected in the dashboard (one OAuth click each)
POSTWIRE_API_KEY in the environment

Auth is Authorization: Bearer $POSTWIRE_API_KEY.

One gotcha worth knowing: the dashboard shows a preview key immediately after signup, before the email is confirmed. That key cannot publish. If the API answers "This is a preview key" (code: "preview_key"), confirm the email and take the key from API & MCP in the dashboard.

How to Use

Base URL: https://postwire.io/api

Check what is connected

curl https://postwire.io/api/me -H "Authorization: Bearer $POSTWIRE_API_KEY"

Returns the plan, the monthly usage, and connections[] — publish only to networks listed there, otherwise the call fails with code: "not_connected" and the offending platforms.

Write a native caption per network

curl -X POST https://postwire.io/api/generate \
  -H "Authorization: Bearer $POSTWIRE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "We shipped streaming uploads: 1GB videos now go through in 11 seconds",
    "platforms": ["linkedin", "x", "bluesky"]
  }'

Returns { "drafts": { "linkedin": {...}, "x": {...}, "bluesky": {...} } }. That object is what per_platform takes below — but show it to the user first, for the reason in the next section.

Confirm Before Publishing

/api/post and /api/schedule are visible writes: they put text under the user's own name, in public, where other people see it. Treat them the way you would treat sending an email as them.

Before either call, show the user:

the exact text that will go out, per network — not the prompt that generated it
which networks it is going to
when it publishes (now, or the exact run_at)

and wait for a yes.

This matters most right after /api/generate. Those drafts are model output: passing them straight into per_platform without showing them means the user finds out what they said by reading their own timeline. Generate, show, confirm, then post.

Publish now

curl -X POST https://postwire.io/api/post \
  -H "Authorization: Bearer $POSTWIRE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "platforms": ["linkedin", "x"],
    "per_platform": { "linkedin": {"text": "..."}, "x": {"text": "..."} }
  }'

Without per_platform, a single text is used everywhere — simpler, but it is the behaviour this tool exists to avoid.

The response is per platform, and one failure does not cancel the rest:

{ "results": [ { "ok": true, "platform": "linkedin", "id": "..." },
               { "ok": false, "platform": "x", "error": "..." } ] }

Schedule instead

curl -X POST https://postwire.io/api/schedule \
  -H "Authorization: Bearer $POSTWIRE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "run_at": "2026-09-01T09:00:00Z",
    "platforms": ["linkedin", "instagram"],
    "photo_url": "https://example.com/image.jpg",
    "label": "Launch announcement"
  }'

run_at is ISO 8601. The schedule endpoint validates connections and the media rules up front, so a post that cannot work is rejected now instead of failing quietly at 7am.

Fill a week from one topic

curl -X POST https://postwire.io/api/week \
  -H "Authorization: Bearer $POSTWIRE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "topic": "what we learned running a one-person SaaS", "platforms": ["linkedin", "x"], "days": 5 }'

Five angles on one topic, queued across five days. Text-only networks only — the video platforms would reject every one of them, and the endpoint says so rather than queueing them to fail.

Errors Worth Handling

code	meaning	fix
`preview_key`	key from before email confirmation	confirm email, use the key in API & MCP
`email_unverified`	mailbox not confirmed yet	open the emailed link
`not_connected`	platform not connected; `platforms[]` lists which	connect it in the dashboard
`media_required`	TikTok/YouTube without video, Instagram without media	add `video_url` or `photo_url`
429	monthly plan limit or a burst guard	check `usage` in `/api/me`

Media Notes

Media is passed by URL (video_url, photo_url); PostWire fetches and forwards the bytes.
TikTok and YouTube videos are streamed in chunks, so they can be up to 1GB. Other networks and hosts that do not send Content-Length are capped at 80MB, because the file has to be held in memory.
POST /api/media/upload-url returns a signed URL to upload a file directly (max 50MB) if you do not have somewhere to host it.

Also Available

PostWire ships an MCP server, so an agent can call these as tools rather than as HTTP requests, and there are n8n templates for the same flows. Both are linked from the dashboard.