Mercurius
Mercurius: A capable self-hosted GraphQL toolkit for Fastify teams using JavaScript or TypeScript. Ranked #28 of 32 in GraphQL Tools by our editors (6.0/10); pricing: Free plan; best for fastify teams serving GraphQL APIs.
At a glance
- Editor score6.0 / 10
- PricingFree plan
- Best forFastify teams serving GraphQL APIs
- Free planYes
- Paid fromFree
- Deployment modelSelf-hosted
- Facts checked21 Sep 2026
Where it wins
- Caching, loaders, JIT compilation, batching, and persisted queries
- Supports subscriptions, federation, gateways, and optional GraphiQL
- Open-source npm package for self-hosted JavaScript and TypeScript apps
Where it doesn't
- Its primary integration is centered on the Fastify server framework
- Self-hosted deployment leaves application operations to the team
- The supported language scope is JavaScript and TypeScript
Our verdict on Mercurius
Mercurius is an open-source GraphQL adapter for Fastify and Node.js applications. It is designed for developers and teams building self-hosted GraphQL APIs with JavaScript or TypeScript. The package provides schema and resolver handling alongside query processing, subscriptions, federation, gateway support, batched queries, persisted queries, loaders, and an optional GraphiQL interface. For teams already building services with Fastify, it brings a broad set of GraphQL server capabilities into the application framework they use.
The pricing model is open source, with a free plan and self-hosted deployment. There are no paid tiers to compare in the published plan structure, so the main product decision is whether Mercurius fits the team’s framework and operational model. Its feature set covers both core request handling and performance-oriented options: query parsing and validation caching, automatic loader integration, just-in-time GraphQL compilation, batched queries, and persisted queries. That makes it suitable for teams that want more than basic schema and resolver support without moving away from Fastify.
Its ecosystem fit is also its clearest boundary. Mercurius is centered on Fastify, rather than presented as a framework-neutral GraphQL server, and it is installed as an npm package integrated into a Fastify application. Federation, gateways, subscriptions, and GraphiQL extend its scope beyond a narrow single-service setup, while JavaScript and TypeScript define the supported language context. Choose Mercurius when Fastify is already part of the stack and the team wants open-source GraphQL tooling with federation and performance features. Consider another option when the primary server framework or language is outside that scope.
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Mercurius pricing
Mercurius fact sheet
| Free plan | Yes |
|---|---|
| Paid from | Free |
| Deployment model | Self-hosted |
| Schema registry | Not verified |
| API explorer | Yes |
| Client code generation | Not verified |
| Operation testing | Not verified |
| Server languages | JavaScript, TypeScript |
| Deployment | Self-hosted |
| Support | Community, Docs |
| Built for | Small business, Mid-market, Enterprise (editorial estimate) |
| Pricing | Free plan |
| Website | mercurius.dev |
| Facts checked | 21 Sep 2026 |
Alternatives to Mercurius
- Apollo GraphOSA broad GraphQL operations platform for teams managing federated APIs at scale.9.4
- HasuraA model-based API platform for composing, governing, and observing data APIs.9.2
- GraphQL HiveA broad GraphQL governance platform with a free tier and self-hosting.9.0
See all Mercurius alternatives →
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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