Mocktail – Free, open-source mock API server with a built-in dashboard
Hi HN, I built the first version of Mocktail years ago. I recently came back to the project, and after a pretty substantial rebuild, v4 is now out. Mocktail is a free and open-source, self-hosted mock API server with a built-in dashboard and database, packaged as a single ~25 MB binary. You can run it locally or on your own infrastructure — no account or hosted service required. You can define endpoints and responses, generate realistic data per request, customize headers, status codes and latency, and inspect incoming requests in real time. With v4, I also added MCP support, so coding…
In plain words
Mocktail is a free, open-source mock API server distributed as a single 25 MB binary for local or self-hosted use. It includes a built-in dashboard and database, allowing developers to define endpoints, generate realistic test data, customize response headers and status codes, and simulate latency. The tool lets users inspect incoming requests in real time and supports optional AI assistance and coding agent integration through MCP support, with no account or external service required.
written from the facts on this page · September 2026
From the sources
Self-hosted mock API server + dashboard in one ~25 MB binary. Define endpoints, generate realistic data, test errors and latency, and inspect live traffic.
A complete mock server, dashboard, and database in one ~25 MB binary. Mix one up locally in seconds — or self-host it on your own infrastructure. { "users" : [ { "id" : "3f9a8c1e" ⟳ uuid "name" : "Ada Lovelace" ⟳ fullName "email" : " [email protected] " ⟳ email "orders" : 14 } ] } Freshly mixed, every request. Model the responses your app expects — headers, delays, even the flaky 401 — and let Mocktail keep the data lively. Write and validate JSON right in Mocktail. Keep responses fixed, generate fresh values on every request ( uuid, email, price, name ), or swap real fields for fake data when you need to anonymize a response. { "id" : "3f9a8c1e" ⟳ uuid "name" : "Ada Lovelace" ⟳ fullName…from getmocktail.com
In the maker’s words, at launch
Hi HN, I built the first version of Mocktail years ago. I recently came back to the project, and after a pretty substantial rebuild, v4 is now out. Mocktail is a free and open-source, self-hosted mock API server with a built-in dashboard and database, packaged as a single ~25 MB binary. You can run it locally or on your own infrastructure — no account or hosted service required. You can define endpoints and responses, generate realistic data per request, customize headers, status codes and latency, and inspect incoming requests in real time. With v4, I also added MCP support, so coding agents can create and manage mocks directly, along with an optional built-in AI assistant using your own API key. Both are completely optional. It’s been fun coming back to something I built years ago and bringing it up to date. I’d love to hear what you think, especially anything you’d change or add.
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