Knock vs Chroma
Notifications-as-a-service: in-app feeds, email, push, SMS, chat via one API
vs. Open-source vector DB designed for AI apps — embeddings-first, dev-friendly
Pricing tiers
Knock
Developer
Free forever. 10K messages, 500 guide users, 500 AI credits/month.
$0 base (usage-based)
Starter
$250/mo. 50K messages, 2.5K guide users, 2K AI credits. Remove branding.
$250/mo
Enterprise
Custom pricing. White-label, i18n, data warehouse, Datadog, SCIM, SAML, HIPAA/BAA.
Custom
Chroma
Cloud — Free
$5 free credits. Great for trying it out.
Free
Cloud — Pro
$100 credits included, then usage-based. Dedicated resources, SOC2, priority support.
$0 base (usage-based)
Self-Host (OSS)
MIT-licensed. Embedded or Docker. Free forever.
$0 base (usage-based)
Cloud — Enterprise
Custom. VPC, compliance, dedicated support.
Custom
Free-tier quotas head-to-head
Comparing starter on Knock vs cloud-free on Chroma.
| Metric | Knock | Chroma |
|---|---|---|
| guide users | 2500 users | — |
| guide users overage | $0.05/user USD/user | — |
| messages monthly | 50000 messages/mo | — |
| messages overage | $0.005/message USD/message | — |
Features
Knock · 13 features
- AI Agents — Autonomous notification drafting & workflow generation.
- Batch + Digest — Group notifications into digests on schedule or window.
- Chat — Slack, Microsoft Teams, Discord.
- Email — Send via SendGrid/Postmark/Resend/Mailgun/AWS SES as relays.
- Guides — In-product messaging, announcements, modals, banners.
- i18n / Localization — Translate templates by user locale.
- In-App Feed — Notification inbox with React/Vue/iOS/Android drop-in components.
- Multi-tenancy — Per-tenant branding, preferences, quiet hours.
- Outbound Webhooks — Subscribe to delivery events.
- Preferences — User + tenant preference center with granular controls.
- Push — iOS (APNs), Android (FCM), Expo, Web Push.
- SMS — Twilio, MessageBird, Telnyx, Vonage as providers.
- Workflows — Visual notification orchestration (branch, batch, delay, throttle).
Chroma · 11 features
- Client-Server Mode — Run Chroma via Docker; clients connect over HTTP.
- Collections — Named groups of embeddings + metadata.
- Distributed (Cloud) — Horizontal scaling on Chroma Cloud.
- Embedded Mode — In-process Python — chromadb.Client() and go. Zero setup.
- Embedding Functions — Plug-in embedders (OpenAI, Cohere, SentenceTransformers, HF).
- Full-Text Search — BM25 + vector hybrid.
- Metadata Filters — Where-clause query language.
- Migration Tools — Import from Pinecone + other stores.
- Multi-Modal — Text + image embeddings (CLIP, etc.).
- Python + JS APIs — Same API shape across both SDKs.
- Serverless Cloud — Pay for storage + queries, auto-scale.
Developer interfaces
| Kind | Knock | Chroma |
|---|---|---|
| CLI | Knock CLI | — |
| SDK | knockapi (Python), knockapi (Ruby), knock-elixir, knock-go, knock-java, @knocklabs/node, @knocklabs/react | chromadb (JS/TS), chromadb (Python) |
| REST | Knock REST API | Chroma HTTP API |
| MCP | Knock MCP Server | Chroma MCP |
| OTHER | Outbound Webhooks | Docker Server, Embedded Mode (in-process Python) |
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