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Haoyang Pang
Haoyang Pang

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Building a Multi-Provider Social Posting API with Automatic Fallback (Open Source)

#opensource #python #api #showdev

I built a Python library that handles social media posting across multiple providers with automatic fallback. If one API fails, it seamlessly switches to the backup. Here's why and how.

The Problem

When building a social media scheduling tool, I hit a common pain point: API reliability. Each social posting service has its quirks:

  • Rate limits
  • Occasional downtime
  • Different pricing tiers

Relying on a single provider felt risky. What if they go down right when your scheduled post needs to go out?

The Solution: Multi-Provider Architecture

I created social-posting-api - a unified interface that:

  1. Tries the primary provider first (PostForMe - cheaper, volume-friendly)
  2. Automatically falls back to LATE if the primary fails
  3. Uses a consistent API regardless of which provider succeeds 
from social_posting import SocialPostingClient

client = SocialPostingClient()

# Posts via PostForMe, falls back to LATE if needed
result = client.post(
    content="Hello from my multi-provider API!",
    platforms=["linkedin", "instagram"],
    media_urls=["https://example.com/image.jpg"]
)

print(f"Posted via: {result.provider}")  # "PostForMe" or "LATE"
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Key Features

Automatic Fallback 

# Try each provider with fallback
for provider in self.providers:
    result = provider.post(content, platforms, media_urls)
    if result.success:
        return result
    last_error = result.error

return PostResult(success=False, error=f"All providers failed: {last_error}")
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Unified Account Management 

# Get connected accounts from any provider
accounts = client.get_accounts()
for account in accounts:
    print(f"{account.platform}: {account.username}")
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Media Upload with Presigned URLs

Both providers use presigned URL patterns for secure media uploads:

def upload_media(self, image_url: str) -> Optional[str]:
    # Download image
    img_data = requests.get(image_url).content

    # Get presigned upload URL from provider
    upload_url = self._get_presigned_url()

    # Upload directly to cloud storage
    requests.put(upload_url, data=img_data)

    return hosted_url
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Multi-Image Carousel Support

Instagram carousels work seamlessly:

result = client.post(
    content="Check out these photos!",
    platforms=["instagram"],
    media_urls=[
        "https://example.com/photo1.jpg",
        "https://example.com/photo2.jpg",
        "https://example.com/photo3.jpg"
    ]
)
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Supported Platforms

  • Twitter/X
  • LinkedIn
  • Instagram (requires media)
  • Facebook
  • TikTok
  • Threads
  • Bluesky
  • Pinterest
  • YouTube

Getting Started 

git clone https://github.com/PHY041/social-posting-api
cd social-posting-api
pip install -r requirements.txt
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Set your API keys:

# .env
POSTFORME_API_KEY=your_key_here
LATE_API_KEY=your_key_here
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Run the test:

python social_posting.py
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Why Open Source?

I'm building CanMarket, an AI-powered marketing tool. This social posting module is one piece of the puzzle, and I figured others might find it useful.

If you're building anything that needs reliable social media posting, feel free to use this as a starting point!

Links

Got questions or suggestions? Drop a comment below!

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