Histeria
Developer Email Infrastructure

Transactional email, without the complexity.

Histeria gives developers a simple way to send, manage, and track transactional email from their applications.

Start sending for freeRead the docs
Delivery Pipeline VisualizerLive Stream
Your Application
Node / Python / Go / React
↓ POST /v1/emails/send
Histeria Engine
Template • Queue • Auth
↓ Async Delivery
Recipient Inbox
Delivered & Tracked
REST API Reference

Send transactional email with one API request.

Trigger emails directly from your backend or microservices. Pass a template slug, recipient address, dynamic JSON variables, and authentication header.

Simple Request Contract
Accepts templateId, to, cc, bcc, optional subject override, and dynamic data object.
Asynchronous Dispatch
API immediately acknowledges requests with a unique email ID and QUEUED status.
Secure Header Auth
Authenticate requests using organization-isolated API keys (`x-api-key`).
POST /v1/emails/send202 Accepted
curl -X POST https://api.histeria.dev/v1/emails/send \
  -H "x-api-key: ck_live_secret_key_123" \
  -H "Content-Type: application/json" \
  -d '{
    "templateId": "order-confirmation",
    "to": "customer@example.com",
    "data": {
      "customerName": "John Doe",
      "orderNumber": "ORD-9812",
      "total": "$149.00"
    }
  }'
Response BodyStatus: QUEUED
{
  "id": "email_98ab71c2",
  "status": "QUEUED"
}
Template Engine

Build once. Send everywhere.

Build visually or work directly with HTML. Both become reusable Histeria templates ready to be triggered via your API.

Drag & Drop Visual Email Composition
Template: order-confirmation
Blocks
Header Logo Block
Text & Variable {{customerName}}
CTA Button Block
Order Summary Table
HEADER BLOCK
Acme Store
TEXT BLOCK WITH DYNAMIC VARS

Hi {{customerName}}, thanks for your order!

View Order #{{orderNumber}}
Compiles to reusable Histeria Template
Trigger from API via templateId or slug
Immutable Versioning

Version your transactional emails safely.

Keep template changes controlled with immutable version history and explicit current active pointers while your production applications continue sending.

Immutable Versions — Modify copy and layout in draft versions without risking live production emails.
Explicit Current Pointer — Set a designated Current Version. The API automatically serves the active version for your templateId.
Status Flags — Manage DRAFT, ACTIVE, and ARCHIVED states with full visibility.
Order Confirmation Template
Slug: order-confirmation
ACTIVE
v3
New Checkout LayoutCURRENT
Updated button styling & item grid
Set Active: Today
v2
Added Tracking URL variable
Previous production version
Archived
v1
Initial HTML layout
Base template version
Archived
Email Observability

See what happened after an email was sent.

Histeria tracks explicit delivery state progression, failure conditions, and recipient engagement timestamps.

Delivery Pipeline States
Step 01
QUEUED
Accepted by API & placed in async send queue
Step 02
PROCESSING
Worker renders template & compiles variables
Step 03
SENT
Dispatched to recipient server
Step 04
DELIVERED
Accepted by recipient mail server
Possible Delivery Outcomes
BOUNCED
Mailbox unavailable or domain rejected
FAILED
Delivery failure during transport
Post-Delivery Tracking Events
OPENED
Recipient opened email (open count & timestamp logged)
CLICKED
Recipient clicked link (click count & timestamp logged)
Developer Observability

Every email. One clear timeline.

Inspect individual email records with queue times, send times, provider message IDs, event history, and HTML preview.

Example Data
Showing 1 record for ORDER-123
ORDER-123DELIVERED & CLICKED
To: customer@example.com | Template: order-confirmation
ID: email_98ab71c2
10:30:01 AM UTC
QUEUED
API request accepted via POST /v1/emails/send
10:30:02 AM UTC
SENT
Dispatched via worker node. Provider Msg ID: msg_77812x
10:30:03 AM UTC
DELIVERED
Accepted by recipient mail server. Delivery time: 1.2s
10:32:18 AM UTC
OPENED
First open logged (Open count: 1)
10:33:04 AM UTC
CLICKED
Recipient clicked tracking URL (Click count: 1)
SMTP Protocol Support

Already using SMTP? Keep your existing workflow.

Configure organization SMTP settings and send transactional email through Histeria without rebuilding your application around a new API.

Universal Compatibility — Works with standard SMTP libraries in Node, PHP, Python, Java, Rails, and Go.
Organization Settings — Custom host, port, TLS/SSL security, sender name, and reply-to configuration.
Built-in Test Dispatch — Send a test email from the dashboard to verify credentials instantly.
Organization SMTP Configuration
Ready for Connection
Developer Security

Control access with production-ready API keys.

Create secure API keys for your production applications and manage them directly from your dashboard with granular name labels, key prefixes, expiration controls, and instant revocation.

One-Time Secret Disclosure

The actual raw API secret key is displayed only once when created. Histeria stores cryptographic hashes for authentication security.

Organization API Keys
Manage production & development application access
Production Store AppACTIVE
Prefix: ck_live_981a...Expires: NeverLast used: Today
Staging ServerACTIVE
Prefix: ck_test_4482...Expires: 30 DaysLast used: Yesterday
Simple Subscription Plans

Start small. Scale when you need to.

Transparent pricing based on your transactional email volume, template needs, and team seats.

Free

Ideal for side projects and early testing

₹0/ month
  • 1,000 emails / month
  • Up to 5 template versions
  • Visual Builder & Code Editor
  • Public REST API & SMTP Support
  • Basic email timeline logs
  • 1 Organization member
Get Started
Most Popular

Pro

For growing SaaS, apps & store platforms

₹999/ month
  • 10,000 emails / month
  • 25 Active template versions
  • Visual & HTML template builders
  • Full email tracking & timeline history
  • SMTP & API key management
  • 5 Organization members
  • Priority email queue processing
Get Started

Business

For high-volume platforms and enterprise apps

₹4,999/ month
  • 1,00,000 emails / month
  • 100 email templates & unlimited versions
  • Dedicated API key controls & expiry
  • Visual & HTML template builders
  • Extended log retention & event history
  • 20 Organization members
  • Priority queue processing
Get Started

Start sending transactional email with Histeria.

Get your API key in seconds and trigger your first application email in minutes with clean developer documentation.

Start sending for freeRead the docs