NewMCP tools — operate your workspace from your agentMCP tools for AI agents

Context-aware
WhatsApp infrastructure
for developers.

Send, receive and auto-reply on WhatsApp from one REST API. No Meta approval, no per-message fees.

Free Sandbox · 500 messages a month · no expiry · paid plans from $15/month

Uses WhatsApp Linked Devices, not Meta’s official API: no approval needed, but a session can drop and need re-pairing. How it works

Replies grounded in your data Per-recipient delivery state Failure reasons, not red dots Session monitoring & re-pair
KS
Kesari StudioWhatsApp · linked number
via ChatRail
Start here

Connect, automate and respond

Connect your numbers, add relevant context and manage the workflow from one workspace.

The API

Send a message with one API call

  • REST over JSON with a bearer token. Nothing to install.
  • connection picks the number you're sending from.
  • Attach a context object and AI replies answer from it.
  • Signed webhooks with an idempotency key on every event.

      
www.chatrail.dev/v1 · bearer token, JSON in and out
Pair any WhatsApp number by QR No templates, no approval queue Text, media, documents, locations Multiple numbers, one workspace AI replies are optional
What ChatRail does

From your app to their phone, and back

Each message is checked, delivered, answered and reported back to your server. You decide what to send and who gets it; ChatRail takes care of getting it there.

An animation of messages travelling from your app through ChatRail to customers on WhatsApp: numbers are checked before sending, messages are delivered and read, customers reply with text, voice notes and photos, every event is posted to your server, and failed deliveries to your server are retried until they succeed.

ChatRail moves messages, it doesn’t mine them. Logs are encrypted at rest and deleted automatically, and AI replies are opt-in. How your data is handled

Your first message is about 10 minutes away. Free Sandbox, no card needed.

How it works

Go live in four steps

Connect a number, send a message and start receiving replies.

Pair a numberLinked device
Waiting for scan
  1. 1 Open WhatsApp on the phone that owns the number
  2. 2 Settings → Linked devices → Link a device
  3. 3 Scan this code. The phone keeps working as normal.
Session persists until the phone unlinks itlinked-device · session
POST https://www.chatrail.dev/v1/messages/text
// Authorization: Bearer $CHATRAIL_KEY
{ "connection": "kesari-studio",
  "to":         "919876500118",
  "body":       "Please confirm your cash-on-delivery order." }
202 Accepted  94ms
{ "id":          "019bf4c3-5a1e-7c02-9d4e-3f6a8b2c1d07",
  "status":      "queued",
  "accepted_at": "2026-09-13T10:22:04Z" }
No SDK — any HTTP client workscurl · fetch · requests
Your endpointPOST /hooks/kesari-studio
message.delivered
message.read
message.received
session.disconnected
Signed with X-ChatRail-Signatureidempotency-key on every event
DeliveryThis week · 412 recipients
Read338
Delivered66
Failed8
+91 (98) •••-0118
+1 (310) •••-0907
Per recipient, not per batchexportable as CSV
Inside the workspace

One place to manage everything

Check connections, schedule recurring reminders, review deliveries and test your setup.

01Connections
01 — Connections

See which numbers are connected

Spot a disconnected number and pair it again before messages are missed.

  • One webhook URL per connection
  • Re-pair by QR without touching the others
Connections3 active
KSKesari Studio+91 (98) •••-0118 Connected
LFLekki Family Clinic+234 (803) •••-0907 Connected
CHColégio Horizonte+55 (11) •••-0042 Re-pair
Optional layer

Let customers ask about any alert

Attach the data when you send. If the customer replies with a question, AI answers from that data, and only that data.

context · invoice_9F24 attached
{
  "invoice": "INV-9F24",
  "total": "PKR 185,000",
  "paid_to_date": "PKR 60,000",
  "due_date": "2026-09-30",
  "late_fee": "2% of the outstanding balance"
}
What happens if I pay after the 30th?
16:41
AI replyYou'd owe the Rs 125,000 still outstanding plus a 2% late fee, about Rs 2,500. Paying on or before 30 September avoids it.
16:41
  • Grounded in your dataIt sees the context you attach, nothing else.
  • Scoped and expiringOne thread, dropped after a window you set.
  • You approve firstDraft mode is the default: a human approves each reply.
  • No key needed10,000 replies a month on Core + AI, or bring your own.
Fits your stack

Connect the tools you already use

Use your preferred AI model and trigger messages from your app, store, CRM or automation tool.

Bring your own model

Use your own AI provider or ours. Pick a model per number.

Anthropic
OpenAI
Google Gemini
DeepSeek
◇ Any OpenAI-compatible endpoint
◇ Self-hosted — set your own base URL

Works with your existing stack

Your app sends the message; replies come back to your webhook. Save group photos to Drive or Dropbox.

Shopify
Stripe
HubSpot
Zendesk
Cal.com
Airtable
Sheets
Supabase
Make
n8n
Zapier
↗ anything that can POST

Manage ChatRail from your coding assistant

Use MCP to check connections, investigate failed deliveries and manage schedules without leaving your editor.

Claude Code · Cursor · Codex · VS Code · any MCP client
✓

Cause found: recipient is not registered on WhatsApp.

Replay in sandbox →
Customer story

Northgate Signals runs its private alert desk on ChatRail.

A paying customer turns continuously monitored events into structured WhatsApp alerts—without asking its private group to watch another dashboard.

ChatRail and Northgate Signals collaboration, connected by the ChatRail magenta rail

Customer outcomeLess time spent checking alerts across systems—and a conversational way to understand the data behind client behaviour.

2,400+alerts delivered60 daysrunning62 / 62recent sends accepted24 msmedian API response

Northgate Signals is the privacy-safe name of a paying ChatRail customer. Identifying details and message data have been anonymised. The 62/62 acceptance rate and 24 ms median reflect one inspected provider log window, not end-to-end WhatsApp delivery.

Built so your number stays yours
  • Runaway loops stop 10 messages per person per 5 minutes, max
  • Refusals explain why the reason and the limit, in plain English
  • Disconnects hold messages queued, not dropped; re-pair by QR
Will my number get banned? →
Production

Built for what goes wrong in production

Retries, duplicates and dropped sessions are handled on our side, and documented so you can handle them on yours.

  • Signed webhooks. Every delivery carries an HMAC-SHA256 signature over a timestamp and the raw body, so you can reject forged or replayed requests. Verify a signature →
  • Each event has one id. It stays the same across every retry, so your handler can skip an event it has already processed. Prevent duplicates →
  • Webhook retries. Timeouts, 5xx, 408 and 429 responses are retried; other 4xx responses are treated as final. Webhook events →
  • Sends can be retried safely. Pass an Idempotency-Key and a retried request returns the original response instead of sending twice. API reference →
  • Dropped sessions recover or say so. A disconnected session retries on its own; one that can’t recover is marked for re-pairing, and queued messages are held, not dropped. Session recovery →
  • Live service checks. The status page checks the API (with its database and Redis), the dashboard and this site in real time. Platform status →
Pricing

Simple pricing per connected number.

Start free and upgrade when you are ready.

Founding priceSubscribe to any paid plan before 30 November 2026 and keep today’s price for 12 months.

Messaging

Sandbox

$0/ month

For testing and personal automations.

  • 1 connected number
  • 500 messages / month
  • 50 AI replies a month to try
  • Basic API and webhooks
  • 7-day message log
Start free
Messaging

Core

$15/ month

For production alerts and workflows.

  • 1 connected number
  • Unlimited messaging, number-safety guardrails
  • Media, groups and scheduling
  • Retries, logs and session monitoring
  • 50 AI replies a month to try
Start with Core
Teams

Team

$79/ month

For agencies and multi-client workspaces.

  • 5 connected numbers
  • Unlimited messaging, number-safety guardrails
  • 50,000 AI replies a month, no API key needed
  • Per-client webhooks and credentials
  • Member access and priority support
  • MCP tools for your coding assistant
Start with Team

Extra number: $8/month · Bring your own model key for unlimited AI replies on Core + AI and Team.

Pay monthly by card, or prepay 3 or 12 months in crypto (12 for the price of 10): USDT, USDC or Bitcoin.

Put your WhatsApp messages on rails.

Your first message is about 10 minutes away. Start on the free Sandbox — no card needed. Pair a number, send from the API and get the reply at your webhook.

Founding priceUpgrade before 30 November 2026 and keep today’s price for 12 months.