Social Media Scheduling APIs for Developers (2026)

Zernio (the API formerly called Late) puts 16 social platforms and 7 ad networks behind one REST shape: POST /v1/posts with content, scheduledFor, a timezone and a platforms array of platform and accountId pairs. Accounts connect through GET /v1/connect/{platform}, which returns the URL where your user authorizes, so it works for products whose customers bring their own accounts. Pricing is per connected account and graduated: the first 2 are free with no card, then $6, $3 and $1 per account as you pass 10 and 100.

The ads APIs set it apart. If your product needs to create or boost paid campaigns next to organic posts, Zernio is the only unified option here that covers Meta, Google, TikTok, LinkedIn, Pinterest, X and ChatGPT ads. Webhooks cover posts (post.published, post.failed, post.partial and more), inbox messages, accounts and ads, signed with HMAC-SHA256 in an X-Zernio-Signature header.

The trade-offs are cost shape and X. Per-account pricing is cheap at 10 accounts ($48) and reasonable at 100 ($318), but a fleet of 500 low-volume accounts costs $718 where Outstand would charge $93. And X's pay-per-request API fees land on your bill whenever you post there.

Breakreach is a social media scheduler whose backend is exposed as a REST API and a hosted MCP server. A post is one request: POST https://api.breakreach.com/v1/posts with content, accountIds, optional media URLs and a time (scheduledAt in the workspace timezone, useNextSlot for the next free slot of the posting schedule, or publishNow). Network options ride along as tiktokSettings, pinterestBoardId, pinterestLink, redditSubreddit and redditFlairText. POST /v1/media re-hosts a public media URL on Breakreach storage, and scheduled posts publish from Breakreach's servers.

For agents, the MCP server at api.breakreach.com/mcp exposes 33 tools, including create_post, update_post (drafts, scheduled and failed posts), get_post_metrics, reply_to_comment, send_message and create_comment_dm_rule (Instagram comment to DM). It accepts OAuth 2.1 with dynamic client registration or an API key. Per-post metrics cover X, Instagram, Facebook, Threads, Bluesky and Reddit, but not TikTok, LinkedIn or Pinterest. One detail to know: delete_post removes a post from Breakreach, never from the network once it's published.

The limits are real. LinkedIn means personal profiles, X has no threads and there are no first comments. Webhooks (post.published, post.failed, account.connected and the Comment to DM events) come with the Pro, Agency and Developer plans. On price, 10 accounts cost $40 against $48 on Zernio, and 100 cost $330 against $318, so pick it for the app and the agent tooling around the API, not for scale pricing.

Ayrshare is the oldest name in this category and prices like it. The request is simple: POST https://api.ayrshare.com/api/post with post, a platforms array and optional mediaUrls and scheduleDate, plus a Profile-Key header when you publish for one of your customers. That profile model is its strength for SaaS: every end user links their own accounts, and one API key drives them all.

2026 brought two changes to plan around. On March 31, X access moved to bring-your-own keys: you register an X developer app and pass its key and secret on every X request. On June 4, Ayrshare shipped an MCP server at api.ayrshare.com/mcp with 27 tools; it authenticates with a static bearer header, which its docs say rules out personal custom connectors in Claude Desktop.

The price reflects the positioning. There's no free tier (the 28-day trial is on Launch), Premium at $149/month covers one profile, and a product with 100 customers lands at $1,228/month on Business. For a funded product that values vendor maturity, that's defensible. For an indie developer, the same core features cost a fraction elsewhere.

Outstand calls itself the unified social media API for AI agents, and its billing is the most different on this page: you pay for posts, not accounts. $19/month includes 3,000 posts across unlimited connected accounts; beyond that it's $0.007 per post up to 10,000 and $0.005 after. At one post per account per day, 100 accounts stay at $19 and 500 accounts cost about $93. The request is POST https://api.outstand.so/v1/posts with accounts, a content string or a containers array (one container per tweet in a thread or per carousel item) and scheduledAt.

The catches are on the platform side. Outstand's own OAuth apps cover LinkedIn, Instagram, Facebook, Threads, Bluesky, YouTube, Pinterest and TikTok; for X, Reddit, Google Business Profile and Vimeo you register an app with the platform first, which its homepage describes as hours to days of paperwork. Scheduling is capped at 30 days ahead, so a long-range calendar has to live in your own database. It reports 12.8M+ posts a month across 500+ companies and 99.92% uptime on its homepage.

Buffer closed its old REST API to new developers years ago, and on May 27, 2026 it shipped a new public API, an MCP server and a CLI, available on every plan including Free. The API is GraphQL at api.buffer.com: a createPost mutation takes text, a channelId and a mode (addToQueue for the next slot of your posting schedule, or customScheduled with a dueAt timestamp), with per-network metadata for threads, first comments, Instagram post types and Pinterest boards. The MCP server lives at mcp.buffer.com/mcp.

It's built for Buffer users, and the limits show it. Every key or app client gets 100 requests per 15 minutes and 3,000 (Free), 7,500 (Essentials) or 15,000 (Team) per 30 days, and MCP connections share that bucket. Media has to be hosted by you, post metrics are limited to personal keys and marked experimental, and a product built on it needs each of its users to have a Buffer account. For a team already running its calendar in Buffer, that's a good trade. For a product that publishes for thousands of customers, pick one of the unified APIs above.

Self-hosted Postiz is the only fee-free route to programmatic publishing at any account count, and for some teams (regulated industries, agencies whose contracts forbid third-party data processors) it's the only architecture that clears legal. You get a real scheduler with a public API, webhooks and an MCP server, all running on your own servers. The API even covers account connection by OAuth URL, next available slot, Reddit flair lookup and post analytics.

Price it honestly, though, because the invoice is in hours. Platforms grant API access to reviewed developer apps, not to software, and standing those up means Meta's App Review, TikTok's separate content-posting audit, X's API access and a dozen smaller processes, each with rejection loops. Then platforms change their APIs and your instance needs updating. A competent team absorbs this; a solo founder usually finds the hosted options cheaper. Postiz Cloud, from $29/month for 5 channels, runs the same software for you.