posterly
Social scheduler for 18 platforms built agent-first: an MCP server and API let AI agents draft, learn your voice, and post directly
A basic compose-queue-publish loop against open-API networks (Mastodon, Bluesky, Telegram) is a weekend build, same as any scheduler. What's specific to posterly and harder to fake is the agent-native layer: an MCP server exposing tools like generate_captions, get_learned_voice, and find_available_slot so a coding agent can draft and post on your behalf, plus a voice model that's actually learned from your posting history and its own performance data rather than a one-off few-shot prompt. Add Google Business Profile review management, per-platform video transcoding, and client approval workflows for agencies, and the moat is upkeep and depth, not the initial compose/publish loop.
Build verification: not recorded. How we judge buildability
What you give up
- 18 maintained platform integrations, including approval-gated ones (Instagram, LinkedIn, TikTok, Facebook, Google Business Profile)
- a voice model trained on your actual post history and what performed well, not a static prompt template
- Google Business Profile review replies and photo management
- client approval portal and content-plan review for agencies managing multiple brands
- per-platform video/image transcoding tuned to each network's limits
- a hosted MCP server + REST API built for agents, not bolted on after the fact
Why people still pay
Anyone can wire an LLM to a caption box; keeping a voice model current against real engagement data, holding pre-approved OAuth apps for the platforms that gate access behind business verification, and exposing a stable MCP/API surface an agent can drive reliably are all ongoing work, not a one-time build. Agencies additionally pay for the client-review layer, which needs its own auth and approval state machine.
Your build guide
The stack, security requirements, and agent rules for a focused replacement.
Before you start
- Runtime and tools: TypeScript, Node, SQLite, a scheduled worker and a React draft/calendar interface.
- Before starting: An approved account for one documented publishing API, its current media/character rules and a sample post; API access and provider charges are separate.
Use these project rules and optional skill references alongside the prompt. Review each skill before adding it to your agent; the AGENTS.md export includes the same guidance.
Project rule — domain: Store CaptionRequest, DraftRevision, Approval, Schedule and DestinationReceipt; agent-created drafts are never automatically authorized for publication.
Project rule — scope and recovery: Keep generation separate from publication and rate-limit both endpoints. No arbitrary remote media fetches or secret-bearing prompts; unsupported networks use manual exports.
Project rule — acceptance: Call the caption endpoint twice with the same request identity, edit the result and queue it; show one draft lineage and publish only the explicitly approved revision.
Project rule — delivery: document real setup commands and permissions; do not claim a build, accuracy level, performance result or security certification that has not been demonstrated.
Recommended skill: web-design-guidelines — review keyboard access, focus, validation, error recovery and the readable work/review interface or HTML report. Follow the maintainer's installation instructions and match its requirements to the chosen runtime.
Recommended skill: sharp-edges — review configuration and API defaults against the app-specific invariants and recovery boundaries above; this is not a security certification. Follow the maintainer's installation instructions and match its requirements to the chosen runtime.
Implementation plan
Phase 1
Pin the working slice and create its example input: Expose an authenticated caption-drafting endpoint and reviewed compose queue, then publish approved text/media to the chosen documented networks. Confirm setup: An approved account for one documented publishing API, its current media/character rules and a sample post; API access and provider charges are separate.
Phase 2
Implement persistence and write-time invariants before decorating the UI: Store CaptionRequest, DraftRevision, Approval, Schedule and DestinationReceipt; agent-created drafts are never automatically authorized for publication.
Phase 3
Connect the working view to real saved state. Freeze the approved content revision at enqueue time. Keep one receipt per destination and stop on revoked credentials or ambiguous publish results; retry only after checking provider state. Offer manual export for unsupported networks.
Phase 4
Expose the app-specific limits and recovery path in context: Keep generation separate from publication and rate-limit both endpoints. No arbitrary remote media fetches or secret-bearing prompts; unsupported networks use manual exports.
Phase 5
Walk through this concrete acceptance case and preserve its exported evidence: Call the caption endpoint twice with the same request identity, edit the result and queue it; show one draft lineage and publish only the explicitly approved revision. Finish the README and backup/restore instructions; report unfinished capabilities explicitly.
Build the following focused alternative to posterly. This is a deliberately limited personal or small-team substitute, not parity with the paid service. WORKING SLICE Expose an authenticated caption-drafting endpoint and reviewed compose queue, then publish approved text/media to the chosen documented networks. SETUP AND ARCHITECTURE Use TypeScript, Node, SQLite, a scheduled worker and a React draft/calendar interface. Prerequisites: An approved account for one documented publishing API, its current media/character rules and a sample post; API access and provider charges are separate. Before integrating anything, record actual versions and permissions, plus model files or provider limits only where used, in the README; make unavailable dependencies visible rather than simulating success. DOMAIN MODEL AND INVARIANTS Store CaptionRequest, DraftRevision, Approval, Schedule and DestinationReceipt; agent-created drafts are never automatically authorized for publication. IMPLEMENTATION CONTRACT Freeze the approved content revision at enqueue time. Keep one receipt per destination and stop on revoked credentials or ambiguous publish results; retry only after checking provider state. Offer manual export for unsupported networks. Provide an input/setup view, the main work view, and a review/export view appropriate to this workflow. Preserve the last saved state if a job or save fails. Include empty, loading, permission-denied, partial and retryable-error states. Log identifiers and error categories without secret values or unnecessary private content. APP-SPECIFIC BOUNDARY AND RECOVERY Keep generation separate from publication and rate-limit both endpoints. No arbitrary remote media fetches or secret-bearing prompts; unsupported networks use manual exports. ACCEPTANCE SCENARIO Call the caption endpoint twice with the same request identity, edit the result and queue it; show one draft lineage and publish only the explicitly approved revision. Also reopen the app after an interrupted operation, confirm the saved record/export remains inspectable, and document the recovery action. These are implementation acceptance requirements, not a claim that this guide has been tested. DELIVERY Deliver a runnable repository with migrations or project-format versioning, a non-sensitive example, environment/permission setup, the exact manual acceptance steps, and a backup/export-and-restore walkthrough. Implement the working slice before optional integrations; list any deferred paid-product capabilities honestly. Do not add capabilities outside the working slice just to resemble the original product. PROJECT RULES FOR AGENTS.md Keep the domain invariants above executable at the write boundary. Propose scope changes before adding providers or permissions. Never fabricate source evidence, publish results, identity matches or successful delivery. Preserve user originals and require an explicit confirmation for destructive changes or external publication.
$ open in your agent (prompt prefilled, you press enter), copy the prompt or copy or download AGENTS.md
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posterly pricing
| plan | monthly | annual (per mo) | what you get |
|---|---|---|---|
| starter | $7 | $5.58 | 5 connected social accounts, 1 seat, 1 brand, 0 link-in-bio pages, 300 AI credits/monthAnnual plan is billed $67/year. |
| pro | $15 | $12 | 12 connected social accounts, 3 seats, 5 brands, 5 link-in-bio pages, 800 AI credits/monthAnnual plan is billed $144/year. |
free tierno free tier
billingmonthly + annual; 7-day trial and 7-day money-back guarantee
hidden costsThe MCP/API is a separate $3/month add-on; the Agency API is $29/month. X publishing can require separately priced X capacity because of X API costs.
pricing sources checked 2026-08-14 · pricing source ↗
Questions about posterly
Can you build your own posterly with AI?
Partly. A basic compose-queue-publish loop against open-API networks (Mastodon, Bluesky, Telegram) is a weekend build, same as any scheduler. What's specific to posterly and harder to fake is the agent-native layer: an MCP server exposing tools like generate_captions, get_learned_voice, and find_available_slot so a coding agent can draft and post on your behalf, plus a voice model that's actually learned from your posting history and its own performance data rather than a one-off few-shot prompt. Add Google Business Profile review management, per-platform video transcoding, and client approval workflows for agencies, and the moat is upkeep and depth, not the initial compose/publish loop.
What does the posterly build prompt cover?
The prompt starts with this scope: Expose an authenticated caption-drafting endpoint and reviewed compose queue, then publish approved text/media to the chosen documented networks. Full-product capabilities excluded from the comparison include: 18 maintained platform integrations, including approval-gated ones (Instagram, LinkedIn, TikTok, Facebook, Google Business Profile); a voice model trained on your actual post history and what performed well, not a static prompt template; Google Business Profile review replies and photo management. Follow the implementation plan and its prerequisites before expanding the build.
How do I use the prompt, AGENTS.md and agent skills?
Start with the posterly prerequisites and stack, then copy the prompt into your coding agent. Save the project rules as AGENTS.md in the project root. Linked skills are optional packages or source instructions for specific tasks; review their current contents and install only those matching the chosen stack. A skill does not supply API credentials or verify the finished app.
How long will this posterly project take?
The catalogue estimate is multi-day for the limited scope. Setup, integration approvals, debugging, deployment and ongoing maintenance can add time. This is an estimate, not a delivery guarantee.
What would I give up by replacing posterly?
18 maintained platform integrations, including approval-gated ones (Instagram, LinkedIn, TikTok, Facebook, Google Business Profile); a voice model trained on your actual post history and what performed well, not a static prompt template; Google Business Profile review replies and photo management; client approval portal and content-plan review for agencies managing multiple brands; per-platform video/image transcoding tuned to each network's limits; a hosted MCP server + REST API built for agents, not bolted on after the fact. Anyone can wire an LLM to a caption box; keeping a voice model current against real engagement data, holding pre-approved OAuth apps for the platforms that gate access behind business verification, and exposing a stable MCP/API surface an agent can drive reliably are all ongoing work, not a one-time build. Agencies additionally pay for the client-review layer, which needs its own auth and approval state machine.
What price is this guide comparing against?
The recorded Pro plan is $15/mo (monthly), checked 2026-07-30. Check the linked pricing source before buying. Building your own also has hosting, API and maintenance costs; the recorded amount is not a guaranteed saving.
What can I use instead of building posterly?
The prior-art section lists Postiz as starting points. Review their current scope, license and maintenance before adopting one.