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The Verdict
This one is genuinely close, and the right pick depends on what you're optimizing for.
Buffer wins on brand trust, its real forever-free plan for up to 3 channels, and a shipped AI Assistant for caption drafting that PostFast doesn't have yet (PostFast's AI Assistant is still a roadmap item under scope review).
PostFast wins on agent-native depth: an official, open-source MCP server with 24 tools (26 via its hosted connector) spanning publishing, analytics, follower history and Social Inbox, full REST API on its cheapest plan, and a comment inbox (TikTok, Instagram, Facebook, Threads) included on every tier including the trial.
Buffer also has an official MCP server (mcp.buffer.com), so this isn't a case of one tool having agent support and the other not; it's a difference in how much of the workspace sits behind that one key from day one.
Choose PostFast if
- +Developers and AI-agent builders automating publishing end to end
- +Teams that want comment management included free at every tier
- +Agencies managing dozens of accounts on one flat-priced plan
- +Anyone who wants full API access without an upsell
Choose Buffer if
- +Solo creators who want to stay free indefinitely on a few channels
- +Marketers who want AI-drafted captions in the same tool they schedule from
- +Anyone who wants the most established name in social scheduling
- +Small teams needing only 1-3 connected channels
Pricing
Which one costs more?
PostFast prices in EUR per workspace tier; Buffer prices in USD per connected channel with volume discounts. These are different currencies and different pricing axes, so treat the comparison as directional, not a converted total.
For a handful of channels Buffer's Free plan and low per-channel rate are hard to beat; once you're paying for more than a few accounts, PostFast's flat tiers start looking more predictable.
$12/mo
starting price
$6/mo
starting price
| Plan / Tier | PostFast | Buffer | Notes |
|---|---|---|---|
| Free | None (7-day trial, no card, full features) | $0/mo for up to 3 channels, forever | Buffer's Free plan does not expire. PostFast has no permanent free tier. |
| Entry paid | Starter: €12/mo, or €10/mo billed annually (4 accounts flat) | Essentials: from $6/mo per channel, or $5/mo per channel billed annually | Buffer's rate drops at volume (down to $1/channel at 51+); PostFast's Starter is a flat price for up to 4 accounts. |
| Team / collaboration | Creator: €29/mo, or €24/mo billed annually (12 accounts, 5 users/workspace) | Team: from $12/mo per channel, or $10/mo per channel billed annually (unlimited team members) | Different axes: PostFast caps users per workspace at a flat price; Buffer charges per channel regardless of team size. |
| Scale | Growth: €49/mo, or €40/mo billed annually (30 accounts) | Volume discount continues (as low as $1/channel at 51+ channels) | No published Buffer tier above Team; its scaling is entirely through the per-channel volume curve. |
| Agency / white-label | Pro (Agency): €99/mo, or €82.50/mo billed annually (120 accounts, white-label branding, priority support) | Not published | We found no dedicated white-label or agency tier in Buffer's published plans. |
| Top tier | Enterprise: €239/mo, or €199/mo billed annually (500 accounts) | Not published | Buffer's highest publicly listed plan is Team; anything larger would be a custom quote. |
Buddy's Take on Pricing
For a very small setup, Buffer wins outright: its Free plan costs nothing and never expires, which PostFast simply doesn't offer.
Past 3-4 channels the comparison gets murkier because the two tools charge on different axes; PostFast's flat per-workspace tiers (€12 to €239) buy a fixed account allowance regardless of team size, while Buffer's per-channel pricing scales with exactly how many channels you connect, at a rate that falls sharply past 10 channels.
Run your own account count through both before deciding; neither pricing model is better in the abstract.
Looking for something cheaper?
These Social Media Automation start lower than both PostFast and Buffer.
Features
Capability comparison
Both tools now describe themselves as agent-ready, but they put different amounts of the product behind that single API key, and only one of them ships a built-in caption writer.
| Capability | PostFast | Buffer |
|---|---|---|
| Free plan | ✗ | ✓ |
| AI caption / content generation | ✗ | ✓ |
| MCP server | ★ | ● |
| Full REST API access | ✓ | ✓ |
| Unified comment / inbox management | ✓ | ✓ |
| Automation integrations (Zapier, Make, n8n) | ★ | ● |
| White-label / agency branding | ✓ | ✗ |
| Platforms supported | ★ | ★ |
The clearest split is AI content generation. Buffer's AI Assistant and AI-powered comment replies are shipped, live, and included on the Free plan. PostFast schedules and publishes what you give it; writing the caption is still your job or your own AI's job, since PostFast's AI Assistant is listed as a roadmap item with scope still under review.
The second split is how much sits behind the API from day one. PostFast's €12 Starter plan includes full REST API and MCP access, so an agent-driven workflow can run on the cheapest tier PostFast sells. Buffer also runs an official MCP server, but our data doesn't break out which of its tiers unlock full API access, so budget-tier automation on Buffer is harder to size up in advance.
Comment management is a wash on paper: PostFast's Social Inbox (TikTok, Instagram, Facebook, Threads, included at every tier and during the trial) and Buffer's Community inbox with AI-assisted replies (included from Free) both exist. Neither vendor's published data tells us the exact platform coverage of Buffer's inbox, so we're not claiming one is broader than the other, only that both are real and both are free.
AI & Integrations
Which fits your stack better?
API access, automation connectors, and AI readiness. The tools that connect to your stack save you the most time.
| PostFast | Buffer | |
|---|---|---|
| MCP ServerConnect to AI assistants (Claude, Cursor) | ✓ | ✓ |
| REST APIBuild custom integrations | ✓ | ✓ |
| ZapierNo-code automation | ✓ | ✗ |
| Make (Integromat)Advanced workflow builder | ✓ | ✗ |
| Security | ||
| SSO | ✗ | ✗ |
| 2FA | ✗ | ✓ |
| Ecosystem | ||
| Support | — | |
Who It's For
Who should choose which?
Choose PostFast if you...
- +You want full API and MCP access from the cheapest paid plan, not gated to a higher tier
- +You're building an AI-agent workflow and want a Social Inbox included at every tier, even during the trial
- +You manage more than a handful of accounts and want one flat price per workspace tier instead of a per-channel bill
- +You don't need a permanent free plan and are fine trialing for 7 days before paying
Choose Buffer if you...
- +You want to stay on a real free plan indefinitely for a small number of channels
- +You want AI-drafted captions built into the product today, not on a roadmap
- +You'd rather work with the established, widely-recognized brand in this category
- +You only need 1-3 channels, where Buffer's per-channel pricing undercuts a flat-tier competitor
Final recommendation
The bottom line
If you want the safety of a free plan you can stay on indefinitely, plus AI-drafted captions in the same tool, Buffer is the lower-risk choice, especially for a small number of channels where its per-channel pricing is genuinely cheap.
If you're building around an AI agent or automation stack and want full API, MCP and a comment inbox available on the cheapest paid tier rather than gated behind an upgrade, PostFast is built for exactly that. Neither is a clear universal winner; run your actual account count and workflow through both before committing.
FAQ
Frequently Asked Questions
No. PostFast offers a 7-day free trial with full features and no credit card required, but there's no permanent free tier. Buffer's Free plan covers up to 3 channels indefinitely.
Yes. Buffer runs an official MCP server at mcp.buffer.com, and our data shows it verified alive. PostFast's MCP server is open source and documented at 24 tools (26 via its hosted connector); Buffer's published tool count and scope aren't available in our data, so we can't say which is more capable.
For 1-3 channels, Buffer's Free plan ($0) or low-end Essentials pricing is likely cheaper than PostFast's €12 Starter, which has no free tier. Once you're past a handful of channels and want full API access at that price point, PostFast's flat €12 Starter becomes more competitive.
Not yet. PostFast schedules and publishes across 11 platforms but does not generate captions; an AI Assistant is listed on its roadmap with scope still under review. Buffer ships an AI Assistant on every plan, including Free.
More on these tools
Joonas Rotko
Author & founder of That Marketing Buddy
I score marketing software for AI-stack fit (MCP, API, agent-readiness), backed by 10+ years in digital marketing. This comparison is based on structured data from 21 tools in the Social Media Automation category.
This page may contain affiliate links. I earn a commission at no extra cost to you. This never influences the comparison.
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