Can Scalar turn an OpenAPI spec into an MCP server?

Yes. Its MCP & Agent product hosts an MCP server built from OpenAPI documents in Scalar's registry, configured in the dashboard with no code. It exposes three fixed tools (summarize the API, search operations, execute a request) rather than one tool per operation, and each operation is set to Search or Execute.

Is Scalar's MCP server free?

Hosted MCP servers are not included on Scalar's Free plan. They start on Pro at $150 a month ($125 billed yearly), with 500 credits a month, and one credit covers 200 successful MCP tool calls. Kaiva Bridge's Free plan includes 10 servers and 200,000 tool calls a month.

Can Scalar connect a database or documents?

Scalar's MCP pages describe OpenAPI documents as the source, with Markdown guides beside them, and do not mention databases, GraphQL or remote MCP servers. Kaiva Bridge connects Postgres, MySQL, MariaDB and SQL Server (read-only), GraphQL, spreadsheets, documents and remote MCP servers.

COMPARISON

Kaiva Bridge or Scalar

Checked 22 Oct 2026, from each product's own docs and pricing pages.

Scalar is an API documentation company whose MCP & Agent product turns the OpenAPI documents in its API registry into a hosted MCP server, with three fixed tools that search the API and run requests instead of one tool per operation. Hosted MCP servers start on its Pro plan at $150 a month. Kaiva Bridge is a managed MCP cloud platform that builds an MCP server from an API spec, a cURL command or Postman collection, a GraphQL endpoint, a database or documents, and has a free plan. Choose Scalar when you already publish your API docs or keep your OpenAPI in Scalar, or your API has hundreds of operations. Choose Kaiva Bridge when the source is a database, documents or an API without a spec, or you want to start free.

Side by side

Scalar and Kaiva Bridge, side by side, checked 22 Oct 2026
What	Scalar	Kaiva Bridge
What it is	ScalarAn API documentation company. Its MCP & Agent product turns OpenAPI documents in Scalar's API registry into a hosted MCP server with three fixed tools: summarize the API, search its operations and execute a request. Scalar also sells API docs and SDK generation and makes an open-source API client.	Kaiva BridgeA managed MCP cloud platform. You connect a source, Bridge builds the tools from it and serves the MCP server.
What it connects	ScalarOpenAPI documents (Swagger 2.0 is upgraded on load), one or several per server, plus Markdown guides served beside the API tools. Its MCP pages do not mention databases, GraphQL or remote MCP servers as sources.	Kaiva BridgeREST APIs from an OpenAPI 3.x or Swagger 2.0 spec, a cURL command or a Postman collection (v2.0 or v2.1); GraphQL APIs (their queries); Postgres, MySQL, MariaDB and SQL Server databases (read-only); CSV spreadsheets; documents (PDF, Word, PNG, JPEG, text and Markdown); and existing remote MCP servers.
How you build a server	ScalarIn the Scalar dashboard, create a server for an API in the registry, choose its operations and set each to Search (looked up only) or Execute (real requests), set authorization and copy the address. Documents reach the registry by upload, URL, CI sync or the CLI; servers can also be created through Scalar's API. No code.	Kaiva BridgeConnect the source in the console, with the CLI (npx @kaiva/bridge push) or from your AI client through the Kaiva Bridge connector, then choose which tools to switch on. No server code to write.
How you run it	ScalarScalar hosts it at an address such as mcp.scalar.com/@team/api, over Streamable HTTP, with a version or environment in the address. Its docs describe serving it on your own subdomain. Each client address is limited to 150 requests a minute.	Kaiva BridgeKaiva runs it. When you publish, the server is live at an address on api.kaiv.ai, over Streamable HTTP.
Sign-in for AI clients	ScalarPrivate by default: team members use a Scalar personal access token. With OAuth Gated, people outside the team sign in by email, Google, Microsoft or SSO if their email or domain is in an access group, with no Scalar account and an optional branded login. Passthrough mode leaves sign-in to your API, including your own OAuth server.	Kaiva BridgeOAuth 2.1 sign-in with a Kaiva account on every plan, so Claude and ChatGPT need no key, or a gateway key limited to the servers you pick.
API credentials	ScalarForward each caller's own credential in a header (not stored), use one shared secret from the team's secret store, or map a different stored secret to each access group. Stored secrets cannot be read back, and agents never receive them.	Kaiva BridgeStored encrypted by Bridge, added to each call on the server side and never sent to the AI client.
Pricing	ScalarHosted MCP servers are not included on Free. Pro: $150 a month ($125 billed yearly) with 500 credits a month. Business: $600 a month ($500 billed yearly) with 2,000. One credit covers 200 successful MCP tool calls; beyond the allowance, $0.057 per credit. Enterprise: custom.	Kaiva BridgeFree: 10 servers and 200,000 tool calls a month, no card. Pro: $19 a month for unlimited servers and 1,000,000 tool calls, then $0.04 per 1,000 calls. Enterprise by contract.
Open source	ScalarThe API reference, API client and OpenAPI tools are open source (MIT). Scalar's own comparison lists the hosted MCP service as closed.	Kaiva BridgeThe CLI is open source (MIT). The platform is not.
Where it runs	ScalarHosted by Scalar. Its pages describe no self-hosted MCP server and point teams that need one inside their own network to other tools.	Kaiva BridgeKaiva's managed cloud. A source must be reachable on the public internet: Bridge refuses private and internal addresses.
Team features	ScalarTeams with Owner, Admin and Editor roles and unlimited viewers; access groups from Pro; SSO and SAML on Business and Enterprise; role-based access control on Enterprise.	Kaiva BridgeOn every plan, per-tool switches and a log of every call. On Pro, SSO, approval before chosen calls and alerts.

Which to choose

Choose Scalar if

You already publish your API docs with Scalar or keep your OpenAPI in its registry: one document then feeds the docs, the SDKs and the MCP server.
Your API has hundreds of operations and you want a tool list that stays small: Scalar's three fixed tools search the API instead of listing every operation.
You also want generated SDKs and a searchable docs MCP server on the same plan.
You give customers access with their own upstream keys: access groups admit them by email or domain and map each group to its own stored key, behind a branded login.
Your API already has its own OAuth server and you want AI clients to sign in there; Scalar forwards the token unchanged.

Choose Kaiva Bridge if

The source is a Postgres, MySQL, MariaDB or SQL Server database, a spreadsheet, documents, a GraphQL API or an existing MCP server, not only an OpenAPI document.
Your API has no OpenAPI spec, but you have a cURL command or a Postman collection.
You want to start on a free plan: 10 servers and 200,000 tool calls a month, no card.
You want each operation as its own named tool, switched on one by one, so the AI client sees exactly the tools you chose.
You want database tools that cannot change data: every query runs in a read-only transaction.
You want a coding agent to create a server from a public API spec with no account (the spec's GET operations, for 72 hours), and claim it into your workspace later.

Using both

Scalar can keep publishing your API docs and SDKs while Kaiva Bridge serves MCP tools for sources Scalar's MCP pages do not cover, such as your database or documents. Both give Streamable HTTP addresses that the same AI client can add.

Questions

Can Scalar turn an OpenAPI spec into an MCP server?: Yes. Its MCP & Agent product hosts an MCP server built from OpenAPI documents in Scalar's registry, configured in the dashboard with no code. It exposes three fixed tools (summarize the API, search operations, execute a request) rather than one tool per operation, and each operation is set to Search or Execute.
Is Scalar's MCP server free?: Hosted MCP servers are not included on Scalar's Free plan. They start on Pro at $150 a month ($125 billed yearly), with 500 credits a month, and one credit covers 200 successful MCP tool calls. Kaiva Bridge's Free plan includes 10 servers and 200,000 tool calls a month.
Can Scalar connect a database or documents?: Scalar's MCP pages describe OpenAPI documents as the source, with Markdown guides beside them, and do not mention databases, GraphQL or remote MCP servers. Kaiva Bridge connects Postgres, MySQL, MariaDB and SQL Server (read-only), GraphQL, spreadsheets, documents and remote MCP servers.

Sources

Read on 22 Oct 2026. Prices and features change, so check these pages before you decide. If something here is out of date, email [email protected] and we will correct it.

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