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JayDB

jaydb.com

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Spec score 9.0 #3 of 28 in Document Databases

What it is

JayDB is a JSON document database with per-user sign-in, aimed at static apps that need user, session, or tenant data without an app-owned backend. Documents are JSON at slash-separated paths, and the first write creates the namespace. Its REST data plane supports GET, PUT, DELETE, and prefix listing. Browser apps can authenticate through OIDC with Authorization Code and PKCE without embedding a client secret. Listed identity providers include Google, GitHub, Microsoft, generic OIDC, and custom OAuth2. The official SDK supports authentication, token refresh, typed document access, and compare-and-swap operations. ETag-based compare-and-swap may reject a write with HTTP 412 if the document changed since it was read. JayDB is available as managed cloud software or as a self-hosted Go engine under the MIT license, using S3-compatible storage or local disk. The free plan is free and includes 1 GB stored, 100,000 reads per month, and 10,000 writes per month; usage hard-stops at those allowances. Metered rates are $0.05 per GB-month of storage, $0.20 per million reads, and $0.50 per million writes.

Spec sheet

What it does
JayDB is a backend-free document database and identity layer that lets static web applications read and write user data directly.Read 15 Oct 2026 · jaydb.com
Purpose
JayDB provides per-user sign-in and a JSON document database so static apps can work without an app-owned backend.Read 7 Oct 2026 · jaydb.com
Intended users
The site presents JayDB for AI-built apps, multi-user or worker-shared documents, and state tied to a user, session, or tenant.Read 7 Oct 2026 · jaydb.com
API
The data plane uses standard REST HTTP and supports GET, PUT, DELETE, and prefix listing.Read 7 Oct 2026 · jaydb.com
License
The project states that its open-source engine is released under the MIT license.Read 15 Oct 2026 · jaydb.com
AI tooling
The independent @jaydb/mcp package exposes get, put, delete, list and health tools for Cursor, Claude Desktop, Antigravity and Cline.Read 15 Oct 2026 · npmjs.com
Authentication
Each tenant exposes an OIDC issuer and supports Authorization Code with PKCE, so browser clients do not need embedded secrets.Read 15 Oct 2026 · jaydb.com
Caching
Recently used documents are served from an in-memory cache and concurrent misses are coalesced into one object-storage read.Read 15 Oct 2026 · jaydb.com
Company identity
The pages reviewed do not state a legal maker name, headquarters or founding year for JayDB.Read 15 Oct 2026 · jaydb.com
Concurrency
HTTP ETags provide optimistic compare-and-swap writes, with failed version checks returning HTTP 412.Read 15 Oct 2026 · jaydb.com
Concurrency limit
The pricing page says sustained concurrent writes to one hot key can cause retries to pile up.Read 7 Oct 2026 · jaydb.com
Data model
Keys are slash-separated paths that hold JSON documents, and the first write creates the namespace automatically.Read 7 Oct 2026 · jaydb.com
Document model
Data is stored as JSON documents addressed by slash-separated hierarchical paths inside namespaces.Read 15 Oct 2026 · jaydb.com
Documentation depth
The documentation site covers quickstart, architecture, CAS, read-modify-write, REST endpoints, embedded Go usage, clustering, metrics and an LLM-readable API specification.Read 15 Oct 2026 · jaydb.com
Durability
Durable data is kept in AWS S3 or compatible object storage such as Cloudflare R2, MinIO or Wasabi.Read 15 Oct 2026 · jaydb.com
Frontend SDK
JayDB publishes a zero-dependency browser package named @jaydb/cloud with typed document operations, token refresh and CAS support.Read 15 Oct 2026 · jaydb.com
Go embedding
The engine can be imported as a pure Go library and run in-process without network hops.Read 15 Oct 2026 · jaydb.com
Identity integrations
The site lists Google, GitHub, Microsoft, generic OIDC, and custom OAuth2 identity providers.Read 7 Oct 2026 · jaydb.com
Identity providers
The hosted service can connect Google, GitHub, Microsoft, generic OIDC and custom OAuth2 identity providers.Read 15 Oct 2026 · jaydb.com
Independent site check
Scamadviser reports a valid SSL certificate and a DNSFilter safe label for jaydb.com.Read 15 Oct 2026 · scamadviser.com
Independent site limitation
Scamadviser reports that the domain owner identity is hidden in WHOIS, traffic rank is low and the domain is young.Read 15 Oct 2026 · scamadviser.com
Limit: contention
JayDB warns that sustained concurrent writes to one hot key can cause retries to pile up and may favor a lock-based database.Read 15 Oct 2026 · jaydb.com
Limit: free usage
Free-tier requests stop with a rate-limit response after the storage, read or write allowance is reached rather than generating overage billing.Read 15 Oct 2026 · jaydb.com
Limit: query features
The product page says JayDB has no field-based secondary indexes, joins, foreign-key constraints, full-text search or aggregation.Read 15 Oct 2026 · jaydb.com
Limit: transactions
The product page says writes cannot be made atomically across multiple documents.Read 15 Oct 2026 · jaydb.com
MCP package license
The @jaydb/mcp npm package is published under MIT and provides a local-server option using npx.Read 15 Oct 2026 · npmjs.com
MCP package metadata
The @jaydb/mcp listing shows version 0.1.0, one published version, two dependencies and 13 weekly downloads at the time indexed.Read 15 Oct 2026 · npmjs.com
Notable limitations
The site says JayDB has no secondary indexes, joins, foreign-key constraints, full-text search, aggregation, or atomic writes across multiple documents.Read 7 Oct 2026 · jaydb.com
Prefix listing
Applications can list keys beneath a path prefix without secondary indexes.Read 15 Oct 2026 · jaydb.com
Pricing limits
Paid usage is metered at $0.05 per GB-month of storage, $0.20 per million reads, and $0.50 per million writes; deletes are free and egress has no per-GB line item under fair use.Read 7 Oct 2026 · jaydb.com
REST API
The stateless API uses GET, PUT and DELETE endpoints under /v1/n/{namespace}/docs and accepts an X-JayDB-API-Key header.Read 15 Oct 2026 · jaydb.com
SDK
The official zero-dependency @jaydb/cloud SDK provides OIDC and PKCE authentication, token refresh, typed document access, and CAS operations.Read 7 Oct 2026 · jaydb.com
SDK collaboration
The @jaydb/cloud SDK listing describes stateless tree ACL invite tokens signed with HMAC-SHA256.Read 15 Oct 2026 · socket.dev
SDK observability
The @jaydb/cloud SDK listing includes counters for reads, writes, listings, conflicts and round-trip latency.Read 15 Oct 2026 · socket.dev
SDK platform support
The independently indexed @jaydb/cloud SDK uses native browser APIs, supports Node.js 18+, and includes TypeScript declarations and generics.Read 15 Oct 2026 · socket.dev
SDK release
The indexed @jaydb/cloud package is version 0.1.0 and was published five days before the crawl shown by the package-security page.Read 15 Oct 2026 · socket.dev
Security statement
The hosted browser flow scopes bearer tokens to individual users and publishes tenant discovery metadata and JWKS endpoints.Read 15 Oct 2026 · jaydb.com
Self-hosting
JayDB says its Go engine can be self-hosted as an embedded library or standalone server using S3-compatible or local storage.Read 15 Oct 2026 · jaydb.com
Storage
The documentation says the engine uses AWS S3 or S3-compatible storage such as Cloudflare R2, MinIO, or Wasabi for durability.Read 7 Oct 2026 · jaydb.com
Storage drivers
The embedded engine documentation lists S3, filesystem and in-memory storage drivers.Read 15 Oct 2026 · jaydb.com
Supported runtimes
The REST interface is documented for JavaScript, TypeScript, Python, Go, Rust, Ruby, PHP, Node.js, Next.js, Cloudflare Workers, Deno, Bun and cURL.Read 15 Oct 2026 · jaydb.com
Write-to-exist
The first PUT to a key automatically creates the namespace and collection without a separate database creation step.Read 15 Oct 2026 · jaydb.com

Plans and prices

Free Free Free every month, forever 1 GB stored · 100,000 reads/month · 10,000 writes/month · usage hard-stops at allowance Read 7 Oct 2026 · jaydb.com
Free Free monthly, forever 1 GB storage · 100,000 reads/month · 10,000 writes/month · hard stop at allowance · no credit card Read 15 Oct 2026 · jaydb.com
Storage metering $0.05 a month per GB-month Metered per megabyte-hour Read 15 Oct 2026 · jaydb.com
Read metering $0.20 a month per million reads Single-read metering Read 15 Oct 2026 · jaydb.com
Write metering $0.50 a month per million writes Single-write metering Read 15 Oct 2026 · jaydb.com
$5 prepaid pack $5, paid once Prepays $6.50 of metered usage 1.3× discount · same metered usage Read 7 Oct 2026 · jaydb.com
$10 prepaid pack $10, paid once Prepays $15 of metered usage 1.5× discount · same metered usage Read 7 Oct 2026 · jaydb.com
Usage pack $10, paid once one-time prepayment Prepays $15 of metered usage · 1.5× discount Read 15 Oct 2026 · jaydb.com

Every JayDB plan and price →

Strong points and limits

Strong points

  • REST API supports GET, PUT, DELETE, and prefix listing.
  • Browser authentication can use PKCE without a client secret.
  • Offers managed cloud and self-hosted deployment.
  • Free plan includes 1 GB stored.

Limits

  • Free usage hard-stops at monthly allowances.
  • No secondary indexes, joins, or full-text search.
  • No atomic writes across multiple documents.
  • Sustained writes to one hot key can pile up retries.

Who it suits

JayDB suits developers building static apps that need user- or tenant-specific documents, including AI-built apps and shared worker data. It offers managed and self-hosted deployment options.

JayDB in depth

Read the full write-up

JayDB is a focused JSON document service that combines per-user identity with storage addressed by predictable paths. It suits static, AI-built, and multi-user apps whose data can stay in individual user, session, or tenant documents. Choose it when straightforward REST access and deployment control matter more than rich querying or cross-document consistency.

Overview

JayDB gives each tenant an OIDC issuer and stores JSON documents under slash-separated keys. The first write creates a namespace automatically, so an app can establish its storage structure as it begins saving data. That path-oriented model works well when the application already knows which document it needs; it is ill-suited to ad hoc discovery across many records.

The engine accepts JSON, MsgPack, and raw document formats, with a maximum document size of 5 MB. It deliberately omits secondary indexes, joins, foreign-key constraints, full-text search, aggregation, and transactions. Those gaps make JayDB a poor choice for relational workflows, search-heavy interfaces, analytics, or any operation that must atomically update several documents.

Key features

REST access and concurrency

The data plane uses ordinary REST HTTP for GET, PUT, DELETE, and prefix listing, which keeps integration practical for browser and server clients. ETag-based compare-and-swap lets a client reject a stale update with HTTP 412 after another writer has changed the document. That protects shared records from silent overwrites, but sustained concurrent writes to one hot key can cause retries to accumulate; heavily contended counters or coordination records need another design.

Identity and SDK

Browser applications can use Authorization Code with PKCE, so they do not need to ship a client secret. Integrations cover Google, GitHub, Microsoft, generic OIDC, and custom OAuth2 providers. The zero-dependency @jaydb/cloud SDK combines OIDC and PKCE sign-in, token refresh, typed document access, and compare-and-swap operations, reducing the amount of authentication and concurrency code an app must maintain.

Storage and deployment

Managed storage uses AWS S3 or compatible services including Cloudflare R2, MinIO, and Wasabi for durability. The MIT-licensed Go engine can be embedded or run as a standalone server, using those S3 options or local disk. That combination gives teams a hosted route and a self-managed route without changing the basic document model.

Pricing

JayDB is freemium. The Free plan costs nothing, billed Free every month forever, and includes 1 GB of storage, 100,000 reads per month, and 10,000 writes per month. Usage hard-stops at those allowances, so it is suitable for small prototypes and low-volume personal or tenant data, not workloads that must continue past a quota.

Paid usage is metered from 0.05 /mo: $0.05 per GB-month of storage, $0.20 per million reads, and $0.50 per million writes. Deletes are free, and egress has no per-GB line item under fair use. A $5 prepaid pack costs 5.00 USD once and prepays $6.50 of metered usage, a 1.3× discount. A $10 prepaid pack costs 10.00 USD once and prepays $15 of usage, a 1.5× discount. These packs suit predictable spend; readers with variable demand should watch read, write, and storage consumption rather than assume a fixed subscription.

Platforms

JayDB supports Android, iOS, Linux, macOS, Windows, web, and API use. It is offered both as managed cloud service and self-hosted software, with the Go engine available for embedding or standalone operation.

Who it's for

JayDB is a strong match for AI-built applications, static front ends, and services storing data scoped to a user, session, worker, or tenant. It also suits teams that want OIDC sign-in bundled with document storage and need the option to run on their own infrastructure. Choose a different database when flexible querying, vector search, full-text search, aggregation, or multi-document transactions is central to the product.

Pros and cons

Pros

Per-tenant OIDC with PKCE supports browser sign-in without exposing a client secret.

REST operations, typed SDK access, and compare-and-swap cover common document workflows with little protocol overhead.

Managed cloud and an MIT-licensed, embeddable Go engine support both convenience and infrastructure control.

Free usage is permanent, while prepaid packs discount metered consumption.

Cons

No indexes, joins, search, aggregation, or transactions limits it to deliberately simple document access.

Hot-key write contention can produce retry pileups under sustained concurrency.

The free tier stops reads and writes at its monthly caps rather than continuing on overage.

Alternatives

Pick Firestore instead if its daily read and write allowances, broader mobile and web positioning, or free trial better fits your rollout. MarkLogic is the alternative for teams needing a larger, enterprise-oriented XML and data platform with developer and enterprise tiers. Choose PouchDB for a free, open-source database spanning mobile, desktop, web, and self-hosted deployments. RavenDB is another freemium option with developer and community capacity plans. eXist-db offers free open-source deployment for academic, non-commercial, and commercial applications. Oracle Autonomous AI Lakehouse provides an always-free autonomous lakehouse option subject to capacity limits. Azure Cosmos DB for NoSQL suits Azure users wanting a free tier with 1,000 RU/s and 25 GB storage. Azure DocumentDB is a self-hostable Linux, macOS, and Windows alternative with a free cluster tier. Browse Document Databases for the wider category.

Verdict

Choose JayDB for a path-based JSON store that pairs per-user authentication with REST access, low metered entry cost, and a genuine self-hosting option. Look elsewhere if your application depends on rich queries, search, analytics, vector retrieval, or atomic changes spanning multiple documents.

Verdict

JayDB provides a focused document store with per-user sign-in and both managed and self-hosted options. Its listed limitations exclude several query and transaction capabilities, so check those against the app’s data needs.

Where Specifiction places it

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