Make Your Automation Reliable with Humans in the Loop
Placet is a purpose-built messenger where AI agents and automation workflows send structured reviews, rich file outputs, and custom UIs. You review, approve, annotate, and respond directly in the conversation.
Data Pipeline
review neededETL & data processing
ETL completed with 3 anomalies detected. Review the flagged rows:
| Row | Customer | Amount | Flag |
|---|---|---|---|
| #248 | Acme Corp | $142,800 | ⚠ Duplicate |
| #512 | Globex Inc | $0.00 | ⚠ Zero amount |
| #819 | Umbrella Co | $-3,400 | ⚠ Negative |
3 of 12,483 rows flagged
How should I handle these?
processed-data.xlsx
Spreadsheet · 2.4 MB
anomaly-report.pdf
PDF · 89 KB
Your Automation Produces More Than Text. Your Tools Don't.
AI agents and automation workflows generate images, render diagrams, fill forms, and need nuanced human feedback. But the tools people use today were never designed for this.
Approvals & Decisions
"Approve? Reply YES/NO" in a text message
Styled buttons, selection lists, or validated forms
Image Review
Download image, open in another app to review
Inline preview with pen, arrow, and text annotation tools
Data & Spreadsheets
File link you download and open externally
Rendered inline as an interactive table in the conversation
Structured Input
Type JSON manually into a chat message
Dynamic forms, selections, or custom plugin UIs
Built for Real Workflows
A clean, familiar interface designed for reviewing and responding to automation messages.
Onboarding Bot
Employee onboarding workflow
New hire Sarah Chen starts Monday. Please complete the onboarding form:
The Human-in-the-Loop Revision Loop
Your automation sends a task, a human reviews and responds, and the workflow continues — or loops back for another revision.
Agent / Script
n8n, LangChain, Python, CLI
POST /messages
Placet API
Validates, stores, delivers
WebSocket / Push
Human Review
Approve, annotate, fill form
Rich UI Response
Result
Structured response
Webhook / Poll
Agent / Script
n8n, LangChain, Python, CLI
POST /messages
Placet API
Validates, stores, delivers
WebSocket / Push
Human Review
Approve, annotate, fill form
Rich UI Response
Result
Structured response
Webhook / Poll
Everything Your Automation Actually Needs
Agents and workflows do more than send text. Placet gives them the tools to send structured reviews, file outputs, custom forms, and interactive UIs. You get a single place to see it all and respond.
Structured Reviews
Five built-in review types: approval buttons, single/multi selection, validated forms, free text with markdown, and freeform JSON for plugin UIs. Every response is structured, traceable, and delivered back automatically.
Rich Media and File Previews
Images, PDFs, videos, audio, DOCX, XLSX, CSV, PPTX, and code files are viewable directly in the chat. Attach any file type and review everything without leaving the platform.
Image Annotation
Review generated images with built-in annotation tools. Draw with pen, add arrows, rectangles, and text overlays. The annotated version is sent back as the review response for precise visual feedback.
Plugin System for Custom UIs
Two files (a JSON manifest and an HTML template) create a new message type. Plugins run in sandboxed iframes with a Bridge API for data, theme, and server-side HTTP proxying. No build step required.
Self-Hostable, No Vendor Lock-In
Run Placet on your infrastructure with a single docker compose command. PostgreSQL for data, S3-compatible storage for files. No cloud dependency, no data leaving your network.
Web Push Notifications
Get browser push notifications when workflows send messages or request reviews. Never miss a time-sensitive approval even when the app is in the background.
Three Ways to Connect
Every automation tool works differently. Placet supports all common integration patterns through a single REST API.
WebSocket (Real-Time)
Instant, bidirectional communication via Socket.io. Messages and review responses appear the moment they happen. Best for interactive workflows and live dashboards.
Webhooks (Async Callbacks)
Register a webhook URL per agent. When a user submits a review, Placet delivers the response payload to your endpoint with tiered retry logic and SSRF protection. Best for n8n, Make, and other platforms.
Long-Polling (Synchronous)
Send a review request and block until the user responds (30s timeout). The response comes back as the HTTP reply. Best for simple scripts and CLI tools that need a synchronous answer.
Up and Running in Minutes
Placet provides a straightforward REST API. Any agent, automation tool, or script can send messages and request human input.
Deploy
Clone the repository and run a single command. Placet starts with PostgreSQL and all services, ready to use in under a minute.
Create Agents
Open Settings in the web UI, generate an API key, and register your agents. Each agent gets its own chat channel and webhook configuration.
Connect and Go
Point your workflows, scripts, or automation tools at the REST API. Send messages, attach files, and request human reviews.
Extend with Custom Message Types
Build any UI component as a message type. Two files, no build step, sandboxed execution. Your automation can send data to custom interfaces, and users respond through them.
Image Annotation
Draw on images with pen, arrows, rectangles, and text overlays. Annotated images are sent back as review responses.
Custom Forms
Render dynamic forms with text, number, select, and textarea fields. Validated responses are returned as structured data.
Custom Action Triggers
Present styled action buttons with custom labels and colors. Users click to trigger specific workflow actions.
Inline HTML Rendering
Render custom HTML content in sandboxed iframes. Build any UI component as a message type with the plugin system.
PDF & DOCX Preview
View PDF documents and Word files directly in the chat. No downloads, no switching apps.
Spreadsheet Preview
Render XLSX and CSV files as interactive tables with headers, styling, and row-level detail — right in the conversation.
Kroki Diagrams
Render Mermaid, PlantUML, D2, and 20+ other diagram formats through a Kroki server integration.
Markdown & Code
Full GitHub-flavored Markdown with syntax-highlighted code blocks, tables, blockquotes, and inline formatting.
Build your own plugin with just 2 files — a plugin.json and a render.html. No build step, no framework lock-in.
Ready to Make Your Automation Reliable?
Deploy Placet in minutes. Open source, self-hostable, and purpose-built for keeping humans in the loop.
Self-host in minutes with Docker Compose & Traefik — on any server.