InstantDB website screenshot

InstantDB

InstantDB (Instant) is a realtime client-side database and Firebase alternative that gives apps a sync engine with multiplayer, offline mode, and optimistic updates by default. It exposes an HTTP Admin API (api.instantdb.com) for server-side InstaQL queries and InstaML transactions, plus auth, storage, presence, and a realtime WebSocket sync layer.

InstantDB publishes 6 APIs on the APIs.io network, including Realtime Sync API, Auth API, Presence API, and 3 more. Tagged areas include Database, Realtime, Sync, Backend, and Local First.

The InstantDB catalog on APIs.io includes 1 event-driven AsyncAPI specification and 1 Spectral governance ruleset.

InstantDB’s developer surface includes authentication, documentation, engineering blog, and 8 more developer resources.

🌐 Visit website 📡 Source on GitHub
47.4/100 developing ▬ flat Agent 39/100 agent ready Full breakdown ↓
scored 2026-07-28 · rubric v0.6
AccessFreemiumSelf serve⚡ Free to try
6 APIs
DatabaseRealtimeSyncBackendLocal First

Kin Score

Kin Score Kin Score How this is scored →
scored 2026-07-28 · rubric v0.6
Composite quality — 47.4/100 · developing
Contract Quality 17.3 / 25
Developer Ergonomics 4.3 / 20
Commercial Clarity 7.9 / 20
Operational Transparency 4.8 / 13
Governance 5.7 / 12
Discoverability 7.4 / 10
Agent readiness — 39/100 · agent ready
Machine-Readable Contract 18 / 18
Agentic Access Contract 10 / 10
MCP Server 0 / 12
Machine-Readable Auth 10 / 10
Idempotency 0 / 9
Stable Error Semantics 0 / 8
Request/Response Examples 7 / 7
Rate-Limit Signaling 7 / 7
Typed Event Surface 6 / 6
Agent Skills 0 / 5
Well-Known Catalog 0 / 4
Consent & Bot Identity 0 / 3
A2A Agent Card 0 / 8
Dry-Run / Simulate Mode 0 / 4
Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. This rating is computed from github.com/api-evangelist/instantdb: open an issue to ask a question, or submit a pull request to add artifacts. Want it done for you? Prioritized profiling — $2,500 →

APIs 6

Individual APIs this provider publishes, each with its own machine-readable definition.

InstantDB Realtime Sync API

The realtime sync transport - a persistent WebSocket at wss://api.instantdb.com/runtime/session over which the client Reactor sends init, add-query, transact, and presence ops a...

InstantDB Auth API

Server-side authentication, tokens, and users.

InstantDB Presence API

Room presence lookups.

InstantDB Query API

InstaQL read queries.

InstantDB Storage API

File upload, listing, and deletion.

InstantDB Transactions API

InstaML transaction writes.

Open Collections 1

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

InstantDB Admin HTTP API

OPEN COLLECTION

Pricing Plans 1

Published pricing tiers and plan structures.

Instantdb Plans Pricing

4 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Instantdb Rate Limits

5 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Instantdb Finops

FINOPS

Event Specifications 1

AsyncAPI definitions for this provider's event-driven and streaming APIs.

InstantDB Realtime Sync (WebSocket)

AsyncAPI 2.6 description of InstantDB's **realtime sync** surface. Unlike a request/response REST API, InstantDB is a sync engine. The client SDK's **Reactor** opens a persisten...

ASYNCAPI

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

InstantDB API Rules

7 rules · 1 errors 5 warnings 1 info

SPECTRAL

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Instantdb Authentication

http · 1 scheme

SECURITY

Instantdb Domain Security

TLSv1.3 · HSTS · DMARC

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Instantdb Agentic Access

14 operations · 12 acting

14 operations · 12 acting

AGENTIC

Resources

Documentation 1

Reference material describing how the API behaves

Documentation
Documentation

Agent Surfaces 1

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess
AgenticAccess

Build 1

SDKs, sample code, and the tooling you integrate with

GitHubOrganization
GitHubOrganization

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity
DomainSecurity
 Authentication
Authentication

Operate 1

Status, limits, changes, and where to get help

RateLimits
RateLimits

Commercial 2

Pricing, plans, and the legal terms of use

Plans
Plans
 FinOps
FinOps

Company 3

The organization behind the API

LinkedIn
LinkedIn
 Website
Website
 Blog
Blog

Source (apis.yml)

apis.yml Raw ↑ 
aid: instantdb
url: https://raw.githubusercontent.com/api-evangelist/instantdb/refs/heads/main/apis.yml
name: InstantDB
kind: company
description: InstantDB (Instant) is a realtime client-side database and Firebase alternative that gives apps a sync engine
  with multiplayer, offline mode, and optimistic updates by default. It exposes an HTTP Admin API (api.instantdb.com) for
  server-side InstaQL queries and InstaML transactions, plus auth, storage, presence, and a realtime WebSocket sync layer.
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  label: Freemium · Self-serve signup
  confidence: high
  source:
  - plans
  - authentication
  generated: '2026-07-22'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/instantdb.png
tags:
- Database
- Realtime
- Sync
- Backend
- Local First
created: '2026-06-20'
modified: '2026-06-20'
specificationVersion: '0.19'
apis:
- aid: instantdb:instantdb-realtime-sync-api
  name: InstantDB Realtime Sync API
  tags:
  - Realtime
  - WebSocket
  - Sync
  - Presence
  image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/apis-json-logo.jpg
  humanURL: https://www.instantdb.com/essays/architecture
  baseURL: wss://api.instantdb.com/runtime/session
  properties:
  - url: https://www.instantdb.com/essays/architecture
    type: Documentation
  - url: https://www.instantdb.com/docs/presence-and-topics
    type: APIReference
  - url: asyncapi/instantdb-asyncapi.yml
    type: AsyncAPI
  description: The realtime sync transport - a persistent WebSocket at wss://api.instantdb.com/runtime/session over which
    the client Reactor sends init, add-query, transact, and presence ops and the server streams query novelty (refresh-ok),
    presence, and broadcasts back to subscribers.
- aid: instantdb:instantdb-auth-api
  name: InstantDB Auth API
  description: Server-side authentication, tokens, and users.
  humanURL: https://www.instantdb.com/docs/http-api
  baseURL: https://api.instantdb.com
  tags:
  - Auth
  properties:
  - type: OpenAPI
    url: openapi/instantdb-auth-api-openapi.yml
  - type: Documentation
    url: https://www.instantdb.com/docs/http-api
  - type: APIReference
    url: https://www.instantdb.com/docs/http-api
  - type: Postman
    url: collections/instantdb.postman_collection.json
  - type: Documentation
    url: https://www.instantdb.com/docs/instaql
  - type: Documentation
    url: https://www.instantdb.com/docs/instaml
  - type: Documentation
    url: https://www.instantdb.com/docs/auth
  - type: Documentation
    url: https://www.instantdb.com/docs/storage
- aid: instantdb:instantdb-presence-api
  name: InstantDB Presence API
  description: Room presence lookups.
  humanURL: https://www.instantdb.com/docs/http-api
  baseURL: https://api.instantdb.com
  tags:
  - Presence
  properties:
  - type: OpenAPI
    url: openapi/instantdb-presence-api-openapi.yml
  - type: Documentation
    url: https://www.instantdb.com/docs/http-api
  - type: APIReference
    url: https://www.instantdb.com/docs/http-api
  - type: Postman
    url: collections/instantdb.postman_collection.json
  - type: Documentation
    url: https://www.instantdb.com/docs/instaql
  - type: Documentation
    url: https://www.instantdb.com/docs/instaml
  - type: Documentation
    url: https://www.instantdb.com/docs/auth
  - type: Documentation
    url: https://www.instantdb.com/docs/storage
- aid: instantdb:instantdb-query-api
  name: InstantDB Query API
  description: InstaQL read queries.
  humanURL: https://www.instantdb.com/docs/http-api
  baseURL: https://api.instantdb.com
  tags:
  - Query
  properties:
  - type: OpenAPI
    url: openapi/instantdb-query-api-openapi.yml
  - type: Documentation
    url: https://www.instantdb.com/docs/http-api
  - type: APIReference
    url: https://www.instantdb.com/docs/http-api
  - type: Postman
    url: collections/instantdb.postman_collection.json
  - type: Documentation
    url: https://www.instantdb.com/docs/instaql
  - type: Documentation
    url: https://www.instantdb.com/docs/instaml
  - type: Documentation
    url: https://www.instantdb.com/docs/auth
  - type: Documentation
    url: https://www.instantdb.com/docs/storage
- aid: instantdb:instantdb-storage-api
  name: InstantDB Storage API
  description: File upload, listing, and deletion.
  humanURL: https://www.instantdb.com/docs/http-api
  baseURL: https://api.instantdb.com
  tags:
  - Storage
  properties:
  - type: OpenAPI
    url: openapi/instantdb-storage-api-openapi.yml
  - type: Documentation
    url: https://www.instantdb.com/docs/http-api
  - type: APIReference
    url: https://www.instantdb.com/docs/http-api
  - type: Postman
    url: collections/instantdb.postman_collection.json
  - type: Documentation
    url: https://www.instantdb.com/docs/instaql
  - type: Documentation
    url: https://www.instantdb.com/docs/instaml
  - type: Documentation
    url: https://www.instantdb.com/docs/auth
  - type: Documentation
    url: https://www.instantdb.com/docs/storage
- aid: instantdb:instantdb-transactions-api
  name: InstantDB Transactions API
  description: InstaML transaction writes.
  humanURL: https://www.instantdb.com/docs/http-api
  baseURL: https://api.instantdb.com
  tags:
  - Transactions
  properties:
  - type: OpenAPI
    url: openapi/instantdb-transactions-api-openapi.yml
  - type: Documentation
    url: https://www.instantdb.com/docs/http-api
  - type: APIReference
    url: https://www.instantdb.com/docs/http-api
  - type: Postman
    url: collections/instantdb.postman_collection.json
  - type: Documentation
    url: https://www.instantdb.com/docs/instaql
  - type: Documentation
    url: https://www.instantdb.com/docs/instaml
  - type: Documentation
    url: https://www.instantdb.com/docs/auth
  - type: Documentation
    url: https://www.instantdb.com/docs/storage
common:
- type: AgenticAccess
  url: agentic-access/instantdb-agentic-access.yml
- type: DomainSecurity
  url: security/instantdb-domain-security.yml
- type: Authentication
  url: authentication/instantdb-authentication.yml
- type: GitHubOrganization
  url: https://github.com/instantdb
- type: LinkedIn
  url: https://www.linkedin.com/company/instantdb
- type: Website
  url: https://www.instantdb.com
- type: Documentation
  url: https://www.instantdb.com/docs
- type: Plans
  url: plans/instantdb-plans-pricing.yml
- type: RateLimits
  url: rate-limits/instantdb-rate-limits.yml
- type: FinOps
  url: finops/instantdb-finops.yml
- url: https://www.instantdb.com/rss.xml
  type: Blog
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com