diff --git a/web/lib/api.ts b/web/lib/api.ts
index b0e3e2b..e8cc3f7 100644
--- a/web/lib/api.ts
+++ b/web/lib/api.ts
@@ -132,6 +132,65 @@ export interface ServerWithKeys extends Server {
   keys: (Assignment & { key: Key })[];
 }
 
+export interface WorkflowStep {
+  step_id: string;
+  name: string;
+  description: string;
+  interpreter: "bash" | "powershell";
+  script: string;
+  declared_outputs: string[];
+  secret_refs: string[];
+}
+
+export interface WorkflowStepRef {
+  step_id: string;
+  order: number;
+  on_failure: "stop" | "continue" | "retry";
+  max_retries: number;
+  overrides?: { script?: string; secret_refs?: string[] };
+}
+
+export interface Workflow {
+  workflow_id: string;
+  name: string;
+  target_server_ids: string[];
+  steps: WorkflowStepRef[];
+}
+
+export interface StepRun {
+  order: number;
+  name: string;
+  status: string;
+  attempts: number;
+  exit_code: number;
+  stdout: string;
+  stderr: string;
+  output_env: Record<string, string>;
+  started_at?: string;
+  finished_at?: string;
+}
+
+export interface ServerRun {
+  server_id: string;
+  hostname: string;
+  status: string;
+  run_env: Record<string, string>;
+  steps: StepRun[];
+  started_at?: string;
+  finished_at?: string;
+}
+
+export interface WorkflowRun {
+  run_id: string;
+  workflow_id: string;
+  name: string;
+  status: string;
+  triggered_by: string;
+  started_at: string;
+  finished_at?: string;
+  server_runs: ServerRun[];
+}
+
 class ApiError extends Error {
   constructor(
     public status: number,
@@ -324,4 +383,73 @@ export const api = {
       body: JSON.stringify(body),
     });
   },
+
+  // Steps
+  listSteps(): Promise<WorkflowStep[]> {
+    return request<WorkflowStep[]>("/steps");
+  },
+
+  createStep(s: Partial<WorkflowStep>): Promise<WorkflowStep> {
+    return request<WorkflowStep>("/steps", {
+      method: "POST",
+      body: JSON.stringify(s),
+    });
+  },
+
+  updateStep(stepId: string, s: Partial<WorkflowStep>): Promise<WorkflowStep> {
+    return request<WorkflowStep>(`/steps/${stepId}`, {
+      method: "PUT",
+      body: JSON.stringify(s),
+    });
+  },
+
+  deleteStep(stepId: string): Promise<void> {
+    return request<void>(`/steps/${stepId}`, { method: "DELETE" });
+  },
+
+  // Workflows
+  listWorkflows(): Promise<Workflow[]> {
+    return request<Workflow[]>("/workflows");
+  },
+
+  getWorkflow(workflowId: string): Promise<Workflow> {
+    return request<Workflow>(`/workflows/${workflowId}`);
+  },
+
+  createWorkflow(w: Partial<Workflow>): Promise<Workflow> {
+    return request<Workflow>("/workflows", {
+      method: "POST",
+      body: JSON.stringify(w),
+    });
+  },
+
+  updateWorkflow(workflowId: string, w: Partial<Workflow>): Promise<Workflow> {
+    return request<Workflow>(`/workflows/${workflowId}`, {
+      method: "PUT",
+      body: JSON.stringify(w),
+    });
+  },
+
+  deleteWorkflow(workflowId: string): Promise<void> {
+    return request<void>(`/workflows/${workflowId}`, { method: "DELETE" });
+  },
+
+  runWorkflow(workflowId: string): Promise<{ run_id: string }> {
+    return request<{ run_id: string }>(`/workflows/${workflowId}/run`, {
+      method: "POST",
+    });
+  },
+
+  listRuns(workflowId: string): Promise<WorkflowRun[]> {
+    return request<WorkflowRun[]>(`/workflows/${workflowId}/runs`);
+  },
+
+  // Runs
+  getRun(runId: string): Promise<WorkflowRun> {
+    return request<WorkflowRun>(`/runs/${runId}`);
+  },
+
+  cancelRun(runId: string): Promise<void> {
+    return request<void>(`/runs/${runId}/cancel`, { method: "POST" });
+  },
 };