Tool guide
Zernio for Threads and X: pricing, API limits and how to use it
Short answer
Zernio is a posting API and MCP service for developers and AI agents that publishes to Threads and X among sixteen networks. As of October 2026 its pricing page charges per connected account: the first 2 are free, accounts 3 to 10 cost $6 a month each, 11 to 100 cost $3 and 101 and up cost $1. X API costs are passed through at X's rates.
At a glance
Facts from the tool's own pages, checked October 2026. Prices are as of October 2026.
- Price (as of October 2026)
- First 2 accounts free; $6 a month each for accounts 3 to 10; $3 for 11 to 100; $1 for 101 and up
- Example from its page
- 10 accounts cost $48 a month, an average of $4.80 per account
- Free tier
- 2 accounts, no credit card, with unlimited posts, analytics and the full API
- Threads
- Text, image, video, carousel and thread sequences; 500 characters per post
- X (Twitter)
- Posts, threads, replies, quotes and polls; 280 characters, 25,000 on Premium
- X API costs
- Passed through at X's exact rates with no markup; a card is required to connect X
- Post limits
- Unlimited posts on every account; Threads allows 250 API posts per 24 hours
- Networks
- Sixteen, per its home page
- Scheduling
- Scheduler, queue slots, calendar, bulk CSV upload, first comment
- AI
- Works with Claude Code, Cursor and Codex through API and MCP
- Audience
- Built for developers and teams with technical resources, per its FAQ
- Enterprise
- Custom terms past 2,000 accounts
Steps
- 1
Create an account
Sign up at Zernio. The first 2 connected accounts are free and need no card.
- 2
Get an API key
Get an API key from your account. Its docs show each call sending the key as a bearer token.
- 3
Connect Threads
Call the connect endpoint for Threads with your profile ID and send the user to the returned URL to authorize with the Instagram account that owns the Threads profile.
- 4
Connect X
Do the same for X. Add a payment method first, because Zernio's X docs say the connect call returns a 402 until a card is on file.
- 5
Create the post
Send a POST to /v1/posts with the platform, the account ID and the content. Use a shorter Threads or X version in customContent when the text is long.
- 6
Schedule or publish
Set publishNow or a scheduled time. For a Threads chain, pass the posts in threadItems, with the first item as the root post.
What Zernio is and who uses it
Zernio presents itself as marketing infrastructure for agents. The home page says one integration covers social, blogs, messaging, voice and ads, and that it uses official platform APIs only. The social product posts, schedules, replies to comments and DMs and pulls analytics through one API. Its features page also lists a content calendar and unlimited team members.
Its FAQ is direct about the audience: Zernio is built for developers and teams with technical resources, and it also works with no-code tools such as n8n, Make and Zapier. The home page lists Claude Code, Cursor, Codex and other agents as tools it works with. This is infrastructure that other products and agents post through.
Zernio pricing as of October 2026
The pricing page says it is usage-based, with every feature included on every account and no plans or seats. You pay per connected social account per month, billed at the end of each billing period. The page prices a Build tier at $0 a month to start and an Enterprise tier with custom terms past 2,000 accounts.
Each rate applies only to accounts within its band. The page's own example shows 10 accounts at $48 a month: 2 free and 8 at $6, an average of $4.80 per account.
- Accounts 1 to 2: free, no credit card
- Accounts 3 to 10: $6 a month each
- Accounts 11 to 100: $3 a month each
- Accounts 101 and up: $1 a month each
- Inbox messages: the first 10,000 sent a month are free, then $1 per 10,000 per its FAQ
The X cost to plan for
X is the one network with a separate cost. The pricing page says X/Twitter API usage is passed through at X's exact rates with zero markup, and its FAQ says X charges per API call on its side. Analytics and inbox sync for X accounts are opt-in, so you control that spend.
Zernio's X docs add that the connect call needs a payment method on the team before it works, and that the rates and a monthly spend cap are listed on its pricing page. If you only post to Threads, the free tier of 2 accounts has no card requirement.
A founder with one Threads account and one X account therefore sits inside the free band of 2 accounts on Zernio's side, while X's own per-call charges still apply to the X account.
Threads and X support, scheduling and limits
The Threads docs list text, image, video, carousel and thread-sequence posts. Limits there: 500 characters, up to 10 images in a carousel, 1 video of up to 5 minutes and 1 GB, and JPEG or PNG images up to 8 MB. Threads needs an Instagram Business or Creator account with Threads enabled, and an account can publish 250 API posts per 24 hours. The docs also warn that a caption cross-posted from a longer-limit network fails at 500 characters, so send a shorter version.
The X docs list posts, threads, replies, quotes and polls, with 280 characters for a free account and 25,000 for Premium, up to 4 images or 1 GIF, and 1 video per post. URLs count as 23 characters.
Scheduling comes through the API with timezone support, queue slots, a calendar and bulk upload by CSV. For the platforms' own rules, read Threads API limits for schedulers and X API posting limits.
AI and agents
Zernio's pages focus on getting posts out reliably across networks. The AI link is on the agent side: it lists Claude Code, Cursor and Codex as tools that work with it, and it offers MCP access so an agent can call the same API.
The pricing page says every feature is included on every account, and this guide follows that page. For a developer that means one set of rates covers the scheduler, the queue slots, the calendar and the API.
Using Zernio with Threadgehog
Threadgehog is a Mac app that writes posts and multi-post threads for Threads and X in a style it learns from about ten example posts. Drafts wait in a review queue, you approve or reject them, and when you approve a Threads post it writes the X version on its own. Approved posts then go to the scheduler you already use: Buffer, Typefully, Publer, Metricool or Postiz. The site is in waitlist mode today, so you can join the waitlist and get the 14-day free trial when it opens. Solo is $29 a month. See the pricing page for the full plan list.
Threadgehog sends approved posts to Buffer, Typefully, Publer, Metricool and Postiz. Its Export only mode gives you the finished posts to paste into your own Zernio calls. If you build a posting pipeline on Zernio, an approved draft is plain text that drops straight into a call. Each batch holds 10, 20, 30 or 50 posts, and if you promote a product the Posts that include your link setting runs from 0 to 100% in steps of 5.
Questions
Does Zernio support Threads?
Yes. Its docs cover text, image, video and carousel posts and thread sequences on Threads, with a 500 character limit and 250 API posts per account per 24 hours.
Does Zernio support X?
Yes. It publishes posts, threads, replies, quotes and polls to X, with X API costs passed through at X's rates and a card required to connect.
How much does Zernio cost as of October 2026?
The first 2 connected accounts are free. Accounts 3 to 10 cost $6 a month each, 11 to 100 cost $3 and 101 and up cost $1.
Is there a free tier?
Yes. The first 2 connected social accounts are free with no credit card, including unlimited posts, analytics and the full API.
Do I need to be a developer?
Its FAQ says Zernio is built for developers and teams with technical resources, and it also works with n8n, Make and Zapier.
How does Zernio work with AI agents?
It works with AI agents such as Claude Code, Cursor and Codex through its API and MCP, so an agent can publish and schedule posts through the same calls you would use.
Can Threadgehog send posts to Zernio?
Threadgehog sends approved posts to Buffer, Typefully, Publer, Metricool and Postiz. Its Export only mode gives you the finished posts to paste into your own Zernio calls.
Sources
- Zernio pricing (checked 2026-10-17)
- Zernio home page (checked 2026-10-17)
- Zernio features (checked 2026-10-17)
- Zernio docs: Threads (checked 2026-10-17)
- Zernio docs: X (checked 2026-10-17)
- Threadgehog pricing (checked 2026-10-17)