Notifyd

notifyd

The notification service your agent can send through and run.
Email, SMS, WhatsApp, push, in-app inbox. One Rust binary. Postgres only. No dashboard: a digest endpoint and an MCP server instead.

Quick Start • Agent operations • API Reference • Architecture • Benchmarks • llms.txt • Contributing

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What it is

Every product needs to send email, texts and in-app notifications. The usual options are a hosted SaaS billed per notification, or a self-hosted stack with MongoDB, Redis and four containers behind a React dashboard.

notifyd is the third option: a single 10 MB binary with PostgreSQL as its only dependency, that sends through the providers you already have (Resend, Cloudflare Email Service, any SMTP, AgentMail, Telnyx, Twilio, Web Push, FCM), with a real delivery engine (priorities, pacing, retries with Retry-After, provider failover, send windows, one-click unsubscribe) and no admin UI at all. Operating it is an API call or an MCP tool, so the person on call can be an AI agent.

your app / your agent ──POST /v1/send──▶ notifyd ──▶ email · sms · whatsapp · push · in-app (SSE)
your agent            ──POST /mcp─────▶ notifyd ──▶ digest · jobs · retries · suppressions · settings

Three instances run in production today, one per company, operated this way.

_{60 s explainer, invented data. MP4 · Remotion source}

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Send in one call

curl -X POST https://notifyd.example.com/v1/send \
  -H "X-Api-Key: sk_myapp_xxx" \
  -H "Content-Type: application/json" \
  -d '{
    "channels": ["email", "in_app"],
    "subscriber_id": "user-1",
    "subject": "Your report is ready",
    "body": "Hey {{first_name}}, the analysis you requested is complete.",
    "vars": {"first_name": "Alice"},
    "priority": "normal",
    "idempotency_key": "report-42-ready"
  }'

Flat REST, curl is the SDK. Retries are safe (idempotency_key), scheduling is a field (scheduled_at), a marketing campaign is POST /v1/batch with thousands of subscribers per call and it lands in the bulk lane so it never delays a password reset. Follow any send with GET /v1/jobs/:id.

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Let your agent run it

Most notification tools were designed for a human clicking through a dashboard. notifyd exposes the operator's job as tools, with the detail a human operator would need:

1. One call says what needs attention. GET /v1/admin/digest ranks findings and tells you the action for each one, in JSON or Markdown:

# notifyd digest — last 1d
Instance: commit e14e6f3, up 3d, email resend (+ smtp fallback), sms telnyx

## Findings
- **warning** — Primary email provider `resend` is resting for 47s after refusing messages; `smtp` is delivering.
  _Nothing lost. Check the primary provider's status page; if it repeats, lower EMAIL_RATE_PER_SEC or move the primary role to the other provider._
- **warning** — Bounce rate 5.3 % over the window (14 bounced / 263 delivered).
  _Above 5 % providers throttle or suspend the sender. Clean the recipient list; suppressions are applied automatically._
- **warning** — 3 job(s) failed in the last 1d (0.1 % of terminal jobs). Top cause: 422 unverified sender domain.
  _Inspect with list_jobs(status=failed); permanent errors need a fix on the caller side, then retry_job._

## Queue          pending 0, retry 2, processing 0
## Outcomes       email/resend 4 812 sent, 3 failed · in_app 1 203 sent
## Latency        email p50 0.6s, p95 2.1s (scheduled → accepted by provider)
## Deliverability delivered 4 790, bounced 14, complained 0, unsubscribed 9

2. The same operations as MCP tools. POST /mcp is a Streamable HTTP MCP server (current spec revision, legacy initialize kept). Add it to Claude Code, Claude Desktop, Cursor or your own agent:

{ "mcpServers": { "notifyd": {
  "type": "http", "url": "https://notifyd.example.com/mcp",
  "headers": { "Authorization": "Bearer ${NOTIFYD_ADMIN_API_KEY}" } } } }

Tool	What the agent can do
digest	Ranked findings with actions, queue, outcomes, latency, deliverability, per project
list_jobs, get_job	Filter by project, channel, status, recipient, time; see provider, attempts, last error
retry_job, cancel_job	Act on a stuck or wrong send
list_projects, update_project	Sender identity (from_email, from_name), channels, inbound rate limit, bulk send_window in the recipients' timezone
list_suppressions, add_suppression, release_suppression	Suppression list with all or marketing scope
template_metrics	Sent, failed, bounced, opened per template
send_test	Prove the pipeline end to end on any channel

Every tool carries readOnlyHint / destructiveHint annotations and an outputSchema. A read-only operator key (READONLY_API_KEY) exposes only the read tools, for an agent that reports but must not act. Every MCP call is audited.

3. Everything an agent needs to integrate is in the repo. docs/llms.txt is the whole API in plain text for a context window; three Agent Skills ship in skills/ (notifyd-operate, notifyd-integrate, notifyd-deploy):

npx skills add rmzlb/notifyd

Published on the official MCP registry as mcp-name: io.github.rmzlb/notifyd (server.json). Full operator guide: docs/AGENT.md.

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Features

Channels

• Email — Resend, Cloudflare Email Service, AgentMail, any SMTP (lettre), attachments, per-project sender identity
• SMS — Telnyx or Twilio, swap with one variable
• WhatsApp — Telnyx
• Push — Web Push (VAPID) or FCM
• In-app inbox — REST + realtime SSE (EventSource), read / archive / star, unread badge, multi-replica through Postgres NOTIFY

Delivery engine

• Priorities — critical, normal, bulk lanes; /v1/batch and campaign tags land in bulk
• Pacing — token bucket per channel (EMAIL_RATE_PER_SEC); a provider 429 pauses that channel for Retry-After without consuming an attempt, other channels keep flowing, and when it resumes the claim order puts critical first
• Retries — 30 s → 2 m → 10 m → 30 m → 2 h with jitter, 4xx fail fast, rejected batches fall back item by item
• Failover — second email provider with a circuit breaker (EMAIL_FALLBACK_PROVIDER)
• Send windows — quiet hours per project, evaluated in each subscriber's timezone
• Scheduling, idempotency, stuck-job reaper, batch idempotency

Governance

• Unsubscribe — RFC 8058 List-Unsubscribe one-click on every marketing email, suppression scopes all / marketing
• Preferences — per-subscriber opt-in / opt-out
• Multi-project — one instance, many projects, isolated by API key, key rotation with a grace period
• PII masking in logs, audit log of every mutation, per-project rate limit

Operations

• Digest, MCP server, Agent Skills, llms.txt
• Metrics — /v1/metrics, /v1/metrics/prometheus, per-template metrics
• Webhooks — delivery events to your endpoints
• Workflows — event-triggered multi-step sequences, state in Postgres
• Templates — {{variable}} substitution, stored per project

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Quick Start

Docker (recommended)

The image reads its configuration from environment variables; no config file to mount.

git clone https://github.com/rmzlb/notifyd.git && cd notifyd
cat > .env <<'EOF'
JWT_SECRET=change-me-32-random-chars-minimum
ADMIN_API_KEY=change-me-32-random-chars-minimum
RESEND_API_KEY=re_xxx
[email protected]
EOF
docker compose up -d          # notifyd + Postgres 16, http://localhost:3400

Create a project and get its API key:

curl -s -X POST http://localhost:3400/v1/admin/projects \
  -H "X-Api-Key: $ADMIN_API_KEY" -H "Content-Type: application/json" \
  -d '{"id":"myapp","name":"My app","channels":["email","in_app"],"from_email":"[email protected]"}'
# → {"project": {"id": "myapp", "api_key": "sk_myapp_…", …}}

Prebuilt image, linux/amd64 and linux/arm64: ghcr.io/rmzlb/notifyd.

Binary, crate, Nix or source

curl --proto '=https' --tlsv1.2 -LsSf https://github.com/rmzlb/notifyd/releases/latest/download/notifyd-installer.sh | sh
brew install rmzlb/tap/notifyd             # macOS and Linux, Homebrew
cargo binstall notifyd                     # prebuilt from the GitHub release
cargo install notifyd                      # build from crates.io
nix run github:rmzlb/notifyd               # flake: packages, devShell, NixOS module
# then
DATABASE_URL=postgres://notifyd:pass@localhost:5432/notifyd \
JWT_SECRET=… ADMIN_API_KEY=… RESEND_API_KEY=… EMAIL_FROM=… notifyd

Release binaries: Linux x86_64 and aarch64, macOS Intel and Apple Silicon. NixOS: services.notifyd.enable = true; with an environmentFile (see flake.nix).

No provider yet? EMAIL_PROVIDER=log prints emails instead of sending them.

Verify

curl http://localhost:3400/v1/health
# → {"status":"ok","db":"ok","version":"0.2.2","commit":"…","uptime_seconds":12}

→ Full setup, TOML alternative, production notes: docs/SETUP.md

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API at a glance

Project endpoints take X-Api-Key: sk_<project>_…; operator endpoints take the admin (or read-only) key, as X-Api-Key or Authorization: Bearer. Inbox endpoints also accept a subscriber JWT.

Method	Endpoint	What it does
POST	/v1/send	Send on one or several channels
POST	/v1/batch	Send to many subscribers (bulk lane, idempotent)
GET	/v1/jobs/:id	Status, provider, attempts, last error
GET	/v1/inbox/:id · /stream	In-app inbox, SSE realtime stream
POST	/v1/workflows/trigger	Trigger an event-based workflow
GET	/v1/admin/digest	What needs attention, with actions
GET	/v1/admin/jobs · POST …/:id/retry	Operator view and actions
PATCH	/v1/admin/projects/:id	Sender, channels, rate limit, send window
POST	/mcp	MCP server (Streamable HTTP)
GET	/v1/metrics/prometheus	Prometheus exposition
GET	/u/:token	One-click unsubscribe landing

→ Every endpoint with examples: docs/API.md, or feed docs/llms.txt to your agent.

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vs. the alternatives

	Novu	Knock / Courier / SuprSend	notifyd
Infra	MongoDB + Redis + 4 containers	Hosted SaaS	Postgres only, one 42 MB image
Setup	30+ min	Signup + dashboard	docker compose up (2 min)
Language	Node.js (multiple services)	N/A (hosted)	Rust (single binary)
Memory	not measured by us	N/A	13 MB idle, 23 MB draining 100k jobs (method)
Throughput	—	quota-bound	44k jobs/s enqueued, 3.5k jobs/s drained (benchmarks)
Provider 429	job fails	managed	channel paused for Retry-After, attempt not consumed, failover provider tried first
Priorities / send windows	❌	✅	✅ critical → bulk lanes, per-subscriber timezone windows
Ops surface	React dashboard	dashboard + API	digest endpoint, MCP server, Agent Skills, Prometheus
Realtime	WebSocket	WebSocket	SSE, native EventSource, multi-replica
Self-hosted	✅ (heavy)	❌	✅ one container per company
Cost	Free tier / paid	per notification	Free forever, MIT

We only publish numbers we measured on notifyd itself; the rest of the table describes shape, not performance. Method, hardware and bias disclaimer in docs/BENCHMARKS.md.

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In-app inbox and TypeScript SDK

import { createNotifydClient } from 'notifyd-sdk';   // pnpm add notifyd-sdk@github:rmzlb/notifyd

const notifyd = createNotifydClient({ url: process.env.NOTIFYD_URL!, apiKey: process.env.NOTIFYD_API_KEY! });
await notifyd.send({ channels: ['email', 'in_app'], subscriberId: 'user-123',
  subject: 'Your report is ready', body: 'Hey {{first_name}}, the analysis is complete.', vars: { first_name: 'Alice' } });

// Browser: subscriber token from your backend, then a plain EventSource
const events = new EventSource(`${url}/v1/inbox/${userId}/stream?token=${jwt}`);
events.onmessage = (e) => { const d = JSON.parse(e.data);
  if (d.type === 'new_notification') showToast(d.notification);
  if (d.type === 'count_update') updateBadge(d.unread_count); };

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Workflows

curl -X POST http://localhost:3400/v1/workflows -H "X-Api-Key: sk_myapp_xxx" -d '{
  "id": "welcome-series", "trigger_event": "user.signup",
  "steps": [
    {"type": "send", "channel": "email", "template": "welcome"},
    {"type": "delay", "duration": "24h"},
    {"type": "condition", "check": "completed_onboarding",
     "if_false": [{"type": "send", "channel": "email", "template": "nudge"}]}
  ]}'

State lives in Postgres and survives restarts.

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Configuration

Environment variables are the primary interface (that is what the image and the compose file use); a notifyd.toml is accepted for local development. Required: DATABASE_URL, JWT_SECRET, ADMIN_API_KEY. Then one provider:

Variable	Purpose
EMAIL_PROVIDER	resend (default when RESEND_API_KEY is set), cloudflare, smtp, agentmail, log
EMAIL_FROM, EMAIL_FROM_NAME	Instance default sender; projects can override
EMAIL_FALLBACK_PROVIDER	Second provider on 429 / 5xx
EMAIL_RATE_PER_SEC	Outbound pacing per replica
SMS_PROVIDER, SMS_FROM	telnyx or twilio with their credentials
PUBLIC_URL	Base URL for one-click unsubscribe links
READONLY_API_KEY	Optional read-only operator key

→ Every variable, per provider: docs/CONNECTORS.md and docker-compose.yml. TOML reference: notifyd.toml.example.

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Architecture

                 ┌──────────────────────── notifyd (one binary) ───────────────────────┐
 HTTP /v1, /mcp ─▶ axum API ─▶ jobs table ─▶ worker: claim (SKIP LOCKED, by priority) │
                 │                              ├─ pacer per channel, channel pause on 429│
                 │                              ├─ connectors (email/sms/whatsapp/push/in-app)
                 │                              ├─ failover breaker, retries, reaper      │
                 │                              └─ webhooks, metrics, audit               │
                 │  SSE hub ◀── Postgres NOTIFY ── (any replica)                          │
                 └───────────────────────────────┬──────────────────────────────────────┘
                                                 ▼
                                           PostgreSQL 16

src/
├── api/              # routes: send, batch, jobs, inbox, subscribers, templates, workflows, webhooks, admin ops, health
├── connectors/       # email (resend, cloudflare, smtp, agentmail, log), sms, whatsapp, push, in_app
├── worker.rs         # claim by priority, batch context, finalize, retries, failover
├── pacing.rs         # token buckets and channel pauses
├── failover.rs       # provider circuit breaker
├── ops.rs            # digest, findings, operator actions
├── mcp.rs            # MCP server (tools, annotations, audit)
├── send_window.rs    # quiet hours in the subscriber's timezone
├── unsubscribe.rs    # List-Unsubscribe tokens and landing
├── sse.rs            # inbox stream, Postgres NOTIFY fan-out
├── workflow_engine.rs, templates.rs, webhooks.rs, deliverability.rs, metrics.rs, pii.rs, middleware.rs
migrations/           # SQL, applied at start-up
skills/               # Agent Skills: operate, integrate, deploy
server.json           # MCP registry entry
flake.nix             # Nix package, devShell, NixOS module
dist-workspace.toml   # cargo-dist: release binaries and installer

~12 000 lines of Rust, no unsafe. 10.8 MB binary, 42 MB image, 13 MB RSS idle, 23 MB while draining 100 000 jobs. → docs/ARCHITECTURE.md

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Status

notifyd is a 0.x used in production by its authors. What it does not do yet: no dashboard (by design), no A/B testing, no APNs, no inbound email parsing, no multi-tenant billing. Breaking changes are announced in release notes; the queue schema is migrated automatically.

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Documentation

📦 Setup	Local dev, Docker, production
🔌 API reference	Every endpoint with curl / TypeScript / Rust examples
🤝 Agent operations	Digest, MCP tools, read-only key, how an agent runs an instance
🔌 Connectors	Providers, environment variables, adding one
🏗️ Architecture	Queue, priorities, pacing, SSE, connectors
📈 Benchmarks	Footprint, throughput, how to reproduce
🚀 Deployments	One instance per company, runbook
📝 Writing	A notification queue on PostgreSQL alone: what SKIP LOCKED does not give you
📣 Visibility	Registries and launch channels
🤖 llms.txt	The API in plain text for agents

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Contributing

Issues and pull requests are welcome; good first issue is the place to start, and big features begin with an issue. Read CONTRIBUTING.md.

git clone https://github.com/YOUR_USERNAME/notifyd.git && cd notifyd
cargo test && EMAIL_PROVIDER=log DATABASE_URL=… JWT_SECRET=dev ADMIN_API_KEY=dev cargo run

License

MIT.

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