PartKit
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Sandbox ·
draft
10
parts
5,601
loc you don't write
74
invariants
~$40.35
/mo @ 10k
Lock
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1 · What are you building?
Team SaaS
multi-tenant subscriptions
10 parts
AI app / API
programmatic, metered
9 parts
Marketplace
two-sided + discovery
7 parts
Back office
internal tooling
5 parts
Capabilities
10 on
✓
auth.session
✓
auth.tenancy
auth.apikey
✓
billing.subscription
⇄
billing.usage
✓
email.transactional
⇄
sms.transactional
⇄
✓
storage.upload
⇄
✓
webhooks.ingest
⇄
webhooks.dispatch
✓
jobs.queue
✓
audit.log
✓
ratelimit.api
flags.feature
search.fulltext
✓
admin.crud
Verified parts
readable · locked · attested
auth.session
Email/password sign-in + server-validated sessions
v1.2.0 · 380 loc · 8 invariants
↗
auth.tenancy
Orgs, members, roles + the row-level access gate
v1.2.0 · 579 loc · 10 invariants
↗
billing.subscription
Subscriptions — plans, payments, entitlement
⇄ Stripe · Paddle
v1.2.0 · 1354 loc · 8 invariants
↗
email.transactional
Transactional email — welcome, receipts, invites
⇄ Resend · Postmark · SES
v1.2.0 · 622 loc · 6 invariants
↗
storage.upload
Presigned direct-to-bucket uploads (S3 wire)
⇄ S3 · R2 · GCS
v1.1.0 · 385 loc · 7 invariants
↗
webhooks.ingest
Verify inbound webhooks — HMAC, replay defense
⇄ Stripe · Standard Webhooks
v1.1.0 · 563 loc · 7 invariants
↗
jobs.queue
Durable background jobs + cron, no extra infra
v1.1.0 · 566 loc · 8 invariants
↗
audit.log
Append-only, un-rewritable event trail
v1.1.0 · 312 loc · 7 invariants
↗
ratelimit.api
Per-key / per-IP fixed-window limits
v1.0.1 · 313 loc · 7 invariants
↗
admin.crud
Schema-driven internal admin over your tables
v1.1.0 · 527 loc · 6 invariants
↗
Your cost · at scale
rates checked 2026-06-13
compare all
audience
10k
users
+ emails · storage · jobs
scaled from active users
Your selection
$40.35
/mo
Cheapest self-host
$39.63
/mo
Supabase bundle
$20.00
/mo
Best-of-breed
$125
/mo
App hosting
Vercel · managed
$0
›
Database
Neon · managed
~$19.00
/mo
›
Authentication
PartKit (self-host) · self-host
$0
›
Transactional email
Resend · PartKit part
~$20.00
/mo
›
File storage
Cloudflare R2 · PartKit part
$1.35
/mo
›
Background jobs
PartKit (self-host) · self-host
$0
›
Rate limiting
In-memory (PartKit) · self-host
$0
›
Incoming webhooks
PartKit (self-host) · self-host
$0
›
backed by a PartKit part ·
external SaaS, swappable
Revenue & margin simulator
Model price · conversion · AI cost — does this stack make money?
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