What is a social media API, and which ones are free?

Short answer

A social media API is the interface a network offers so that software can post, read or manage on a person’s behalf. Of the eight APIs we read about on 10 October 2026, only X states a price: it charges per request. The others describe no fee and gate use another way: Meta, TikTok, LinkedIn and Pinterest by review or audit, YouTube by a daily quota, Bluesky by rate limits only. A unified API is a service in front of several of these, so one integration reaches many networks. Mellow Hub is one.

Written by the Mellow team · Updated October 10, 2026, sources read October 10, 2026

What a social media API is

A network publishes a set of web endpoints. An app registers with the network, a person signs in and grants it permission, and the app then calls the endpoints for that person: to publish a post, to read counters or comments, or to manage replies. Meta describes the Instagram Platform in these terms: a collection of APIs for Instagram professional accounts, where app users can publish content, get insights and moderate comments.

Two things decide what you can actually do, and they are not the same on every network: which accounts the API serves, and what review stands between a test app and one that other people can use.

The eight, one by one

Read on 10 October 2026, from each network’s own developer pages.

Network	Who it serves	The step before other people can use it	Price and limits the page states
Instagram	Professional (Business or Creator) accounts only	Standard Access is the default and is enough for accounts you own or manage. Accounts you don’t manage need Advanced Access: App Review and Business Verification	No price on the page. 100 API-published posts per account in 24 hours; a carousel counts as one
Threads	A Threads profile that grants your app permissions	A Meta app with the Threads use case. People without a role on the app can grant publishing permission only after App Review and once the app is published	No price on the page. 250 API-published posts per profile in 24 hours, and 1,000 replies
TikTok	A creator who authorizes your app for the video.publish scope	Register an app, add the Content Posting API, get the scope approved, then pass an audit to post publicly	No price on the page. Until audited: private posts only, and up to 5 users in 24 hours. About 15 posts a day per creator, shared across every app that uses Direct Post
YouTube	A channel whose owner authorizes the app	A project with the YouTube Data API enabled	No price on the page. Default quota: 100 searches, 100 uploads and 10,000 other units a day; more by request
LinkedIn	A member, through Share on LinkedIn; a Company Page, through the Community Management API	Share on LinkedIn: add the product in the developer portal. Community Management is a vetted product: apply, then move from a Development tier to a Standard tier	No price on the pages
X	An account that authorizes the app	Credits bought in the Developer Console	Pay per use: creating a post costs $0.015 per request, and $0.200 when the post has a URL; no subscriptions
Pinterest	An account that authorizes the app	Trial access on approval. Standard access after a video of the app completing an action through the API	No price on the page. Under Trial access, Pins and Boards created are visible only to their creator
Bluesky	An account that logs in	The page describes no application or review step	No price on the page. 5,000 points an hour and 35,000 a day, where creating a record costs 3 points

Details behind the table:

Instagram and Threads both belong to Meta, and Meta’s content publishing guide and Threads overview carry the post limits. Permissions for Threads publishing are listed on its get started page.
TikTok. Its Direct Post guide says content posted by an unaudited client is limited to private viewing. Its content sharing guidelines add that an API client should be meant for a wide audience, and name a tool that only uploads to accounts you or your team manage as not acceptable.
YouTube. The Data API overview gives the default quota and the form to ask for more. The upload reference says videos uploaded from unverified API projects are not restricted to private viewing mode.
LinkedIn. Share on LinkedIn uses the w_member_social permission. The Community Management API is for Pages and carries analytics too.
X states its prices on its own page and says they are subject to change.
Pinterest explains Trial and Standard access. Bluesky’s limits are on its rate limits page.

What “free” means here

None of the pages we read except X’s states what an app pays. That is not the same as free of effort: on the other seven the cost is the registration, the review and the compliance work, and for YouTube a daily quota. If you only post to accounts you own or manage, Meta’s Standard Access is meant for that. Other networks do not make it that easy: under Pinterest’s Trial access the Pins you create are visible only to you, and even a sole user needs a video of the OAuth flow to reach Standard access. If other people will sign in to your app, expect review on every network in the table that has one.

A unified social media API

A unified API is a service that has done that work once and exposes one set of calls for many networks. You send a post to it, and it sends the post to each network’s API. What it cannot change is the networks’ own rules: Instagram still serves professional accounts only, and a TikTok post still waits on TikTok’s audit.

Questions worth asking of any unified API: which networks and account types it covers, whether it checks each network’s rules before sending, whether it can post with a different caption per network, how it prices (per post, per network, per account), and what stops an agent calling it from publishing something nobody approved. One guide compares several services on what each says about itself.

Mellow Hub as a unified API

Mellow Hub is one. It publishes to 9 networks, Instagram, TikTok, YouTube, X, LinkedIn, Threads, Bluesky, Pinterest and Facebook, through a REST API at /api/hub/v1 and an MCP server at /mcp, with the same functions behind both. The person who owns the account creates the API key or approves the OAuth grant, and it carries the channels, the mode (review or autopilot), a daily ceiling and an expiry they chose. A validation call is free, publishes nothing and returns every problem in a post at once, naming the network.

Hub reaches the networks through a publishing provider that holds their app approvals, so the person using Hub registers no app and goes through no review on each network. For X, for example: Hub posts through its provider's X app, so you need no X developer account or API credits of your own. The calls, in order, are in the guide to scheduling social media posts with a REST API.

Hub is paid: plans start at $19 a month (Solo), after a 7-day trial with a card on file that costs nothing if you cancel before it ends, and a monthly plan's first month is 20% off. Publishing is unlimited on every plan, under a fair-use ceiling that stops automated floods (900 publications a month on Solo). One publication is one post on one account, so a post sent to five networks counts as five. There are no automatic overage charges.

Questions people also ask

Which social media APIs are free?

Of the eight APIs we read about, X is the only one whose page states a price: it charges per request and says prices can change. The other seven describe no fee, and limit use by review, audit or quota instead.

Do I need approval to post through a network’s API?

It depends on the network. Meta’s Standard Access is the default and is enough for accounts you own or manage; for other people’s accounts Meta requires App Review and Business Verification. TikTok keeps API posts private until an audit. Pinterest makes Pins created under Trial access visible only to their creator, and Standard access needs a video of the app’s OAuth flow, even for a sole user. LinkedIn’s Share on LinkedIn is added as a product in the developer portal, while Pages need an application.

Can I post to a personal Instagram account through an API?

No. Meta’s Instagram Platform serves Instagram professional accounts, which are Business or Creator accounts. A personal account has to be switched to a professional one first.

What is the difference between a posting API and an MCP server?

A posting API is a set of web endpoints a program calls. An MCP server exposes functions in a form an AI assistant can call by itself, which its own answer explains. Mellow Hub offers both, and the same functions sit behind each, under the same key or grant.

Why is my API post private on TikTok?

TikTok’s Direct Post guide says content posted by an unaudited API client is restricted to private viewing, and the content sharing guidelines say its accounts must be private at the time of posting. Making posts public is what the audit is for.

Sources

Other companies’ features change. Every statement about them rests on these pages, as they read on the date above.