Communication · openapi

Slack API Mock Server

Web API

Mock the Slack Web API for bots and integrations. Post messages, open conversations, react — all locally. Carbon keeps channel and user state between calls so multi-step flows behave the way a real workspace would.

Quickstart

npx carbon-api emulate --catalog slack

Runs on http://localhost:8787 by default. No account, no signup.

Try it

Real HTTP against the local replica.

Create a conversation

curl -X POST http://localhost:8787/conversations \
  -H 'content-type: application/json' \
  -d '{"name":"example"}'

List them back (state persists)

curl http://localhost:8787/conversations

What's covered

Carbon compiles the entire spec — these are just the resources most integrations reach for first.

conversations
users
files
reactions

Under the hood

Everything Carbon gives you comes with this emulator — for free.

· Stateful CRUD — writes persist across requests.
· Snapshots — freeze and restore the whole world with one command.
· Chaos presets — inject latency, 5xx, and network errors on demand.
· Deterministic — the same requests produce the same responses in CI.

Slack docs →All emulators