Based on your requirement to target Instagram, Facebook, X (Twitter), and LinkedIn using a free tier, here is how the options break down and which one is the most viable path.
First, the direct API approach using X API v2 on a free tier is no longer feasible for this use case. As of recent changes, X has discontinued its free tier for developers, moving to a pay-per-use model that starts at $0.015 per plain post (and jumps to $0.20 per post if it contains a link). This eliminates the "Direct API" route if keeping costs at absolute zero is the main goal.
Therefore, using a Unified API or automation platform is your best route for a free solution. Here is how the two main options compare:
1. Make.com (The Best Free Automation Choice)
Make.com is a visual workflow builder that connects to social media platforms without you having to write the API integrations yourself.
- Free Plan Limits: 1,000 "credits" (operations) per month and up to 2 active scenarios.
- Platform Support: Fully supports Facebook, Instagram, LinkedIn, and X.
- How it works for you: You can create one scenario (workflow) in Make.com. Your Next.js backend sends a single webhook to Make.com when you publish a post. Make.com then takes that data and uses 4 operations to post it to Instagram, Facebook, X, and LinkedIn.
- Capacity: At 4-5 operations per blog post (1 webhook trigger + 4 social posts), the 1,000 monthly operations limit means you could theoretically publish around 200 blog posts per month for completely free.
2. Ayrshare (The Unified Developer API)
Ayrshare is an API specifically built to handle multi-platform social media posting.
- Free Plan Status: Ayrshare does not have a permanent free tier; they only offer a 14-day or 28-day free trial.
- Alternative: An alternative API called Upload-Post offers a permanent free tier of 10 uploads per month (supporting 2 social profiles) without requiring a credit card. However, 10 uploads a month is quite restrictive for a growing business.
The Recommended Path
For a completely free setup that hits all four of your target platforms (Instagram, Facebook, X, and LinkedIn), Make.com is the superior choice.
It allows you to bypass the new paid constraints of the X API, handles the complex authentication for Meta (Facebook/Instagram) and LinkedIn, and gives you a generous 1,000 operations per month for free.