# Fastify vs Ktor

**Leader by vioscaleAI score:** Fastify

| Attribute | Fastify | Ktor |
|---|---|---|
| **vioscaleAI score** | 70 (78% (high)) | 57.8 (68% (medium)) |
| activity.commits_last_30d | 20 | 98 |
| adoption.dependent_repos | 16,712 | 484 |
| adoption.github_stars | 37,232 | 14,542 |
| content.faq | `[{"answer":"A Node.js web framework optimized to handle high request volumes with minimal overhead, featuring a plugin system, JSON Schema validation, and native TypeScript support. It is indexed under Web Frameworks.","source":"https://fastify.dev","question":"What is Fastify?","confidence":0.6},{"answer":"Fastify is open source, so it can be self-hosted and used at no licence cost. It is released under the MIT licence. Pricing changes often, so verify at source before relying on it.","source":"https://fastify.dev","question":"Is Fastify free to use?","confidence":0.6},{"answer":"Fastify supports the web and a command-line interface. Platforms we have not confirmed are simply not listed here rather than ruled out.","source":"https://fastify.dev","question":"What platforms does Fastify support?","confidence":0.6},{"answer":"Yes. Fastify can be deployed cloud / SaaS and self-hosted, so it does not have to run on the vendor's infrastructure.","source":"https://fastify.dev","question":"Can Fastify be self-hosted?","confidence":0.6},{"answer":"We have confirmed 26 integrations for Fastify, including Next.js, Apollo Server, Angular, PostgreSQL, MongoDB, Redis, Elasticsearch and Swagger/OpenAPI, plus 18 more. This is what we could verify from public sources, so the vendor may support others we have not indexed.","source":"https://fastify.dev","question":"What does Fastify integrate with?","confidence":0.6},{"answer":"Yes. Fastify is published under the MIT licence, a permissive licence that generally allows commercial use and modification. Licence terms can change between releases, so verify against the repository for the version you intend to use.","source":"https://github.com/fastify/fastify","question":"Is Fastify open source?","confidence":0.95}]` | `[{"answer":"Ktor is an open-source framework for creating asynchronous server and client applications, from microservices to HTTP clients. Built on Kotlin and coroutines, it emphasizes simplicity, lightweight design, and extensibility. It is indexed under Web Frameworks.","source":"https://ktor.io/","question":"What is Ktor?","confidence":0.6},{"answer":"Ktor is open source, so it can be self-hosted and used at no licence cost. It is released under the Apache-2.0 licence. Pricing changes often, so verify at source before relying on it.","source":"https://ktor.io/","question":"Is Ktor free to use?","confidence":0.6},{"answer":"Yes. Ktor is published under the Apache-2.0 licence, a permissive licence that generally allows commercial use and modification. Licence terms can change between releases, so verify against the repository for the version you intend to use.","source":"https://github.com/ktorio/ktor","question":"Is Ktor open source?","confidence":0.95}]` |
| deployment.options | `{"cloud":true}` | `{"cloud":true,"on_prem":true,"self_hosted":true}` |
| description.long | A Node.js web framework emphasizing fast request handling and low resource consumption while maintaining strong security, input validation, and developer experience. | A Kotlin framework that uses asynchronous I/O and coroutines to build server-side, client-side, and microservice applications. |
| features.capabilities | `{"language":"JavaScript/TypeScript","api_first":true,"api_routes":true,"async_model":"event-loop-async","file_routing":true,"cli_scaffolding":true,"openapi_autogen":true,"language_runtime":"JS/TS","typescript_first":true,"websocket_support":true,"dependency_injection":true}` | `{"language":"Kotlin","api_routes":true,"hot_reload":true,"typescript_first":false}` |
| integrations.count | 28 | - |
| integrations.list | `[{"name":"Next.js"},{"name":"Apollo Server"},{"name":"Angular"},{"name":"PostgreSQL"},{"name":"MongoDB"},{"name":"Redis"},{"name":"Elasticsearch"},{"name":"Swagger/OpenAPI"},{"name":"WebSocket"},{"name":"JWT"},{"name":"Helmet"},{"name":"Sentry"},{"name":"RabbitMQ"},{"name":"CORS"},{"name":"CSRF"},{"name":"OAuth2"},{"name":"Kubernetes"},{"name":"Firebase","native":false,"category":"auth"},{"name":"Mongoose","native":false,"category":"database"},{"name":"TypeORM","native":false,"category":"database"},{"name":"OAuth","native":false,"category":"auth"},{"name":"GraphQL","native":false,"category":"api"},{"name":"Swagger","native":false,"category":"documentation"},{"name":"OpenAPI","native":false,"category":"documentation"},{"name":"React","native":false,"category":"frontend"},{"name":"Vue","native":false,"category":"frontend"},{"name":"GCP Cloud Storage","native":false,"category":"storage"},{"name":"Casbin","native":false,"category":"authorization"},{"name":"ObjctionJS","native":false,"category":"database"},{"name":"AWS Lambda","native":false,"category":"cloud","direction":"outbound"},{"name":"Svelte","native":false,"category":"frontend","direction":"outbound"},{"name":"AMQP","native":false,"category":"messaging","direction":"bidirectional"},{"name":"Express","native":false,"category":"framework","direction":"outbound"},{"name":"Koa","native":false,"category":"framework","direction":"outbound"},{"name":"Hapi","native":false,"category":"framework","direction":"outbound"},{"name":"Nuxt","native":false,"category":"framework","direction":"outbound"},{"name":"Stoplight Elements","native":false,"category":"documentation","direction":"outbound"},{"name":"Server-Sent Events","native":false,"category":"protocol","direction":"outbound"},{"name":"TypeBox","native":true,"category":"library","direction":"outbound"},{"name":"Valkey","native":false,"category":"caching","direction":"outbound"}]` | - |
| language.primary | JavaScript | Kotlin |
| license.spdx | MIT | Apache-2.0 |
| platform.support | `{"cli":true,"web":true}` | `{"web":true}` |
| pricing | `{"type":"open_source","sourceUrl":"https://fastify.dev","retrievedAt":"2026-09-07T13:15:46.651Z"}` | `{"type":"open_source","freeTier":true,"sourceUrl":"https://ktor.io/","retrievedAt":"2026-08-13T23:07:06.179Z"}` |
| pricing.free_tier | yes | yes |
| pricing.model | commercial | open_source |
| pricing.price_level | free | free |
| release.cadence_days | 4 | 27 |
| release.history | `[{"url":"https://github.com/fastify/fastify/releases/tag/v6.0.0-alpha.4","date":"2026-09-17T07:53:08Z","type":"prerelease","version":"v6.0.0-alpha.4"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.12.5","date":"2026-09-16T10:19:43Z","type":"stable","version":"v5.12.5"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.12.4","date":"2026-09-11T09:19:29Z","type":"stable","version":"v5.12.4"},{"url":"https://github.com/fastify/fastify/releases/tag/v6.0.0-alpha.3","date":"2026-09-04T09:21:10Z","type":"prerelease","version":"v6.0.0-alpha.3"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.12.2","date":"2026-09-04T08:20:39Z","type":"stable","version":"v5.12.2"},{"url":"https://github.com/fastify/fastify/releases/tag/v6.0.0-alpha.2","date":"2026-08-19T01:54:36Z","type":"prerelease","version":"v6.0.0-alpha.2"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.12.1","date":"2026-08-18T19:51:41Z","type":"stable","version":"v5.12.1"},{"url":"https://github.com/fastify/fastify/releases/tag/v6.0.0-alpha.1","date":"2026-08-13T15:57:10Z","type":"prerelease","version":"v6.0.0-alpha.1"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.12.0","date":"2026-08-13T15:55:21Z","type":"stable","version":"v5.12.0"},{"url":"https://github.com/fastify/fastify/releases/tag/v6.0.0-alpha.0","date":"2026-08-11T08:32:37Z","type":"prerelease","version":"v6.0.0-alpha.0"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.11.3","date":"2026-08-08T06:55:46Z","type":"stable","version":"v5.11.3"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.11.2","date":"2026-08-03T08:21:47Z","type":"stable","version":"v5.11.2"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.11.1","date":"2026-08-03T08:10:10Z","type":"stable","version":"v5.11.1"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.11.0","date":"2026-07-30T09:32:16Z","type":"stable","version":"v5.11.0"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.10.0","date":"2026-07-05T09:37:06Z","type":"stable","version":"v5.10.0"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.9.0","date":"2026-06-28T08:21:36Z","type":"stable","version":"v5.9.0"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.8.5","date":"2026-04-14T12:09:02Z","type":"stable","version":"v5.8.5"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.8.4","date":"2026-03-23T10:31:20Z","type":"stable","version":"v5.8.4"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.8.3","date":"2026-03-23T10:20:21Z","type":"stable","version":"v5.8.3"},{"url":"https://github.com/fastify/fastify/releases/tag/v5.8.2","date":"2026-03-07T09:42:46Z","type":"stable","version":"v5.8.2"}]` | `[{"url":"https://github.com/ktorio/ktor/releases/tag/3.6.0","date":"2026-09-18T09:58:55Z","type":"stable","version":"3.6.0"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.5.2","date":"2026-08-04T12:08:07Z","type":"stable","version":"3.5.2"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.5.1","date":"2026-06-29T08:05:31Z","type":"stable","version":"3.5.1"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.5.0","date":"2026-05-18T06:57:48Z","type":"stable","version":"3.5.0"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.4.3","date":"2026-04-23T11:20:32Z","type":"stable","version":"3.4.3"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.4.2","date":"2026-03-30T13:37:19Z","type":"stable","version":"3.4.2"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.4.1","date":"2026-03-04T14:20:52Z","type":"stable","version":"3.4.1"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.4.0","date":"2026-01-23T08:55:39Z","type":"stable","version":"3.4.0"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.3.3","date":"2025-11-27T12:13:53Z","type":"stable","version":"3.3.3"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.3.2","date":"2025-11-05T14:08:06Z","type":"stable","version":"3.3.2"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.3.1","date":"2025-10-10T06:19:56Z","type":"stable","version":"3.3.1"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.3.0","date":"2025-09-12T11:59:39Z","type":"stable","version":"3.3.0"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.2.3","date":"2025-07-29T14:18:09Z","type":"stable","version":"3.2.3"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.2.2","date":"2025-07-14T11:45:21Z","type":"stable","version":"3.2.2"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.2.1","date":"2025-07-04T08:57:57Z","type":"stable","version":"3.2.1"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.2.0","date":"2025-06-13T12:19:28Z","type":"stable","version":"3.2.0"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.1.3","date":"2025-05-06T11:52:28Z","type":"stable","version":"3.1.3"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.1.2","date":"2025-03-28T09:27:52Z","type":"stable","version":"3.1.2"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.1.1","date":"2025-02-25T11:49:42Z","type":"stable","version":"3.1.1"},{"url":"https://github.com/ktorio/ktor/releases/tag/3.1.0","date":"2025-02-12T11:44:49Z","type":"stable","version":"3.1.0"}]` |
| security.scorecard | 8.3 | 4.5 |
| security.vulnerabilities | `{"count":17,"source":"https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=npm&package_name=fastify&per_page=100","last_12m":12,"max_severity":"HIGH"}` | `{"count":1,"source":"https://advisories.ecosyste.ms/api/v1/advisories?ecosystem=maven&package_name=io.ktor%3Aktor-client-core-jvm&per_page=100","last_12m":0,"max_severity":"MODERATE"}` |

## Capabilities (Web Frameworks)

| Capability | Fastify | Ktor |
|---|:--:|:--:|
| **Core** |  |  |
| Rendering model | - | - |
| File-based routing | ✓ | - |
| Language | JavaScript/TypeScript | Kotlin |
| **Rendering** |  |  |
| Server components | - | - |
| Streaming SSR | - | - |
| **Fullstack** |  |  |
| Built-in API / backend routes | ✓ | ✓ |
| **DX** |  |  |
| First-class TypeScript | ✓ | ✗ |
| Fast refresh / HMR | - | ✓ |
| **Deployment** |  |  |
| Edge runtime support | - | - |

*Source: vioscaleAI. Generated 2026-10-16T20:07:54.410Z. "-" = undocumented, not absent.*