How to Post to Multiple Social Media Platforms With One API

Publishing content across multiple social media platforms is one of the most common requirements for modern apps. Whether you're building a social media scheduler, a SaaS product with social features, or an AI content generator, you need a reliable way to post to Twitter, Instagram, YouTube, TikTok, and more — without maintaining separate integrations for each platform.

In this guide, we'll walk through how to use PostPeer's API to publish content to multiple platforms with a single HTTP request.

Prerequisites

Before you start, you'll need:

• A PostPeer account (sign up for free)
• An API key from your PostPeer dashboard
• At least one connected social media account

Step 1: Get Your API Key

After signing up, navigate to your PostPeer dashboard. You'll find your API key in your project settings. This key authenticates all your API requests.

# Your API key looks like this
x-access-key: pp_live_abc123...

Step 2: Connect Social Accounts

Before you can post, your users need to connect their social media accounts. PostPeer handles the OAuth flow for each platform — you don't need to set up developer apps on Twitter, Facebook, or any other platform.

Each connected account gets a unique accountId that you'll use when targeting platforms in your API requests.

Step 3: Make Your First Post

Here's how to publish the same content to Twitter, Instagram, and Facebook with a single request:

curl -X POST https://api.postpeer.dev/v1/posts \
  -H "x-access-key: your-api-key" \
  -H "Content-Type: application/json" \
  -d '{
    "content": "Just shipped a new feature! Check it out.",
    "platforms": [
      { "platform": "twitter", "accountId": "acc_tw_123" },
      { "platform": "instagram", "accountId": "acc_ig_456" },
      { "platform": "facebook", "accountId": "acc_fb_789" }
    ]
  }'

PostPeer returns a response with per-platform results:

{
  "postId": "post_abc123",
  "status": "published",
  "platforms": [
    {
      "platform": "twitter",
      "status": "published",
      "platformPostUrl": "https://x.com/youruser/status/123456789"
    },
    {
      "platform": "instagram",
      "status": "published",
      "platformPostUrl": "https://instagram.com/p/abc123"
    },
    {
      "platform": "facebook",
      "status": "published",
      "platformPostUrl": "https://facebook.com/post/789"
    }
  ]
}

Step 4: Add Media

PostPeer supports images, videos, GIFs, and carousels. Pass media URLs in the mediaItems array:

curl -X POST https://api.postpeer.dev/v1/posts \
  -H "x-access-key: your-api-key" \
  -H "Content-Type: application/json" \
  -d '{
    "content": "Our new office setup!",
    "mediaItems": [
      { "url": "https://example.com/photo.jpg", "type": "image" }
    ],
    "platforms": [
      { "platform": "twitter", "accountId": "acc_tw_123" },
      { "platform": "instagram", "accountId": "acc_ig_456" }
    ]
  }'

PostPeer validates media against each platform's requirements (dimensions, file size, format) before publishing.

Step 5: Use Platform-Specific Options

Some platforms support unique features. You can pass platform-specific data alongside your content:

curl -X POST https://api.postpeer.dev/v1/posts \
  -H "x-access-key: your-api-key" \
  -H "Content-Type: application/json" \
  -d '{
    "content": "Thread about our launch...",
    "platforms": [
      {
        "platform": "twitter",
        "accountId": "acc_tw_123",
        "platformSpecificData": {
          "threadItems": [
            { "text": "1/ We just launched PostPeer..." },
            { "text": "2/ It supports 7+ platforms..." },
            { "text": "3/ Try it free at postpeer.dev" }
          ]
        }
      },
      { "platform": "threads", "accountId": "acc_th_456" }
    ]
  }'

This posts a thread on Twitter while publishing a single post on Threads.

Error Handling

If a post fails on one platform, PostPeer still publishes to the others. You get per-platform status in the response:

{
  "postId": "post_abc123",
  "status": "partial",
  "platforms": [
    {
      "platform": "twitter",
      "status": "published",
      "platformPostUrl": "https://x.com/youruser/status/123456789"
    },
    {
      "platform": "instagram",
      "status": "failed",
      "error": "Image aspect ratio not supported"
    }
  ]
}

Failed posts don't count against your quota, so you can retry with adjusted content.

What's Next

• Schedule posts: Add a publish_at timestamp to schedule content for later
• Set up webhooks: Get real-time notifications when posts publish or fail
• Pull analytics: Fetch engagement data for published posts

Check out the PostPeer docs for the full API reference, or sign up for free to start building.