notifyd MCP server

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What it is

Your app has to tell people things: a password reset, a shipped parcel, a newsletter, a red badge in the corner. notifyd is the small server that does all of it, so your code makes one call and never has to think about providers, rate limits, retries or time zones again.

                 ┌───────────────────────────── notifyd ──────────────────────────────┐
your app ─────▶  │ POST /v1/send ─▶ queue ─▶ priority ─▶ pacing ─▶ retry ─▶ failover  │ ─▶ email · sms · whatsapp
                 │                                                                    │    push · in-app · telegram · slack · discord
your agent ───▶  │ POST /mcp ─▶ digest · jobs · retry · suppressions · settings       │
                 └───────────────────────── PostgreSQL only ──────────────────────────┘

• Small and fast. One 12 MB binary, a 14 MB image to pull, 13 MB of RAM idle. It accepts 44 000 notifications per second and drains 3 500 per second on a laptop (method). No Redis, no message broker, no dashboard to host: PostgreSQL is the only dependency.
• Nothing gets lost. A password reset always goes before a campaign. When a provider says "slow down", that channel pauses for exactly the time asked and resumes in priority order; when it fails, a second provider takes over. Retries, idempotency and quiet hours in each recipient's time zone are built in.
• Your providers, your data. Resend, Cloudflare Email, any SMTP, AgentMail, Telnyx, Twilio, smsmode, APNs, Web Push, FCM. Self-hosted, MIT.
• Operated by an API or an AI agent. No admin UI: a digest endpoint says what needs attention and what to do, and the same operations are MCP tools, so the person on call can be an agent.

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

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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 works; TypeScript and Python clients exist. 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. Runnable examples in every language: examples/.

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Run it from a terminal

The same binary is the operator's CLI, against any instance (the server host has ADMIN_API_KEY in its environment, so it just works there):

notifyd digest                       # what needs attention, with the action for each finding
notifyd jobs --status failed         # --project, --channel, --topic, --recipient, --since 24h, --limit, --json
notifyd job <id>                     # provider, attempts, delivery events
notifyd retry <id>                   # re-queue after fixing the cause
notifyd send-test --project myapp --channel email --to you@example.com
NOTIFYD_URL=https://notifyd.example.com NOTIFYD_ADMIN_API_KEY=… notifyd digest   # from your laptop

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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. The digest comes to you. DIGEST_NOTIFY=telegram:<chat id> (or a Slack / Discord webhook) and the findings above land in your chat when something needs attention; notifyd digest --to telegram:… sends one now.

4. 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, Twilio or smsmode, swap with one variable
• RCS — smsmode (BASIC / TEXT auto-selection, quick replies, click-to-call, rich cards and carousels)
• WhatsApp — Telnyx
• Push — APNs natively (.p8 token auth, HTTP/2, badge, sound, thread id, silent pushes, dead tokens dropped), Web Push (VAPID), 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
• Segments — batch to "plan = pro and country in FR, BE" with a small filter vocabulary compiled to bound SQL; preview the count first
• Scheduling, idempotency, stuck-job reaper, batch idempotency

Governance

• Unsubscribe — RFC 8058 List-Unsubscribe one-click on every marketing email, suppression scopes all / marketing
• Topics and preferences — a topic on any send ("tips", "billing"); subscribers opt out per topic and channel, honoured at enqueue; the unsubscribe page offers "this topic only" before "all marketing"
• 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
• Open and click tracking — own pixel and signed redirect links for every email provider, on marketing email by default (transactional links stay untouched), opened_at / clicked_at on the job, off per project or per request
• 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_FROM=notifications@yourdomain.com
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":"hello@yourdomain.com"}'
# → {"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 a list of subscribers or to a segment filter (bulk lane, idempotent)
POST	/v1/segments/preview	Count and sample the subscribers a segment matches
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 · /:id · POST …/:id/retry · /admin/send-test	Operator view and actions (also the CLI's transport)
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 app containers	Hosted SaaS	Postgres only, one 14 MB image
Setup	30+ min	Signup + dashboard	docker compose up (2 min)
Language	Node.js (multiple services)	N/A (hosted)	Rust (single binary)
Memory at idle	1.1 GB across 6 containers (measured)	N/A	13 MB, 23 MB while draining 100k jobs (method)
Images to pull	1.4 GB	N/A	14 MB
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

Every number in this table was measured by us; the Novu figures come from its own community docker-compose, idle, on the same machine and with the same tool as ours. Method, hardware and bias disclaimer in docs/BENCHMARKS.md.

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Clients

Both clients cover the whole API (send, batch, jobs, subscribers, preferences, templates, workflows, suppressions, inbox) and raise a typed error on any non-2xx answer.

TypeScript / JavaScript — npm i github:rmzlb/notifyd until the notifyd-sdk package lands on npm this week; the package name and the import below do not change (Node 18+, browsers, edge runtimes; zero dependencies)

import { createNotifydClient } from 'notifyd-sdk';

const notifyd = createNotifydClient({ url: process.env.NOTIFYD_URL!, apiKey: process.env.NOTIFYD_API_KEY! });

const { jobIds } = await notifyd.send({
  channels: ['email', 'in_app'], subscriberId: 'user-42',
  subject: 'Your order shipped', body: 'Hi {{first_name}}, parcel {{parcel}} is on its way.',
  vars: { first_name: 'Alice', parcel: 'FR-2041' }, idempotencyKey: 'order-2041-shipped',
});
const job = await notifyd.getJob(jobIds[0]);   // status, provider, attempts, delivery events

// Browser inbox: subscriber token from your backend, live updates over EventSource
const inbox = createNotifydClient({ url, subscriberToken });
const stream = await inbox.openInboxStream('user-42', { onMessage: (e) => {
  const event = JSON.parse(e.data);
  if (event.type === 'new_notification') showToast(event.notification);
  if (event.type === 'count_update') updateBadge(event.unread_count);
} });

Python — pip install "git+https://github.com/rmzlb/notifyd.git#subdirectory=clients/python" until notifyd-sdk lands on PyPI this week (3.9+, sync and asyncio, httpx only) — clients/python

from notifyd import Notifyd

nd = Notifyd(os.environ["NOTIFYD_URL"], api_key=os.environ["NOTIFYD_API_KEY"])
result = nd.send(channels=["email", "in_app"], subscriber_id="user-42",
                 subject="Your order shipped", body="Hi {{first_name}}, parcel {{parcel}} is on its way.",
                 vars={"first_name": "Alice", "parcel": "FR-2041"}, idempotency_key="order-2041-shipped")
print(nd.get_job(result["job_ids"][0])["status"])

Any other language: the API is flat JSON over HTTP and docs/llms.txt is the whole contract on one page.

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Workflows

Multi-step sequences triggered by an event, state in Postgres, survive restarts. Steps run in order; a condition jumps to a step index.

curl -X POST http://localhost:3400/v1/workflows -H "X-Api-Key: sk_myapp_xxx" -d '{
  "id": "welcome-series", "name": "Welcome series", "trigger_event": "user.signup",
  "steps": [
    {"type": "send", "channel": "email", "template": "welcome"},
    {"type": "delay", "duration_secs": 86400},
    {"type": "condition", "field": "payload.plan", "operator": "eq", "value": "pro", "on_true": 4},
    {"type": "send", "channel": "email", "template": "nudge"}
  ]}'

curl -X POST http://localhost:3400/v1/workflows/trigger -H "X-Api-Key: sk_myapp_xxx" \
  -d '{"event": "user.signup", "subscriber_id": "user-42", "payload": {"plan": "free"}}'

Step types: send, delay, condition (inbox.is_read or payload.<key>) and digest (collect events for a while, then send one message). Full script: examples/welcome-series.sh.

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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, twilio or smsmode with their credentials
PUBLIC_URL	Base URL for one-click unsubscribe links and Twilio and smsmode SMS delivery status
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

~14 000 lines of Rust, no unsafe. 12 MB binary (16 MB static musl in the image), 14 MB image to pull and 31 MB on disk, 13 MB RSS idle, 23 MB while draining 100 000 jobs. → docs/ARCHITECTURE.md

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Status

notifyd is a 0.x running in production for three companies. Not done yet: Swift and Kotlin packages; no dashboard, A/B testing or inbound email by design. Order and sizes in docs/ROADMAP.md. Breaking changes are announced in release notes; the queue schema is migrated automatically.

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