diff --git a/src/backend/app/api/monitoring.py b/src/backend/app/api/monitoring.py
new file mode 100644
index 0000000..489d7ba
--- /dev/null
+++ b/src/backend/app/api/monitoring.py
@@ -0,0 +1,333 @@
+"""Monitoring API endpoints for Mission Control."""
+
+from __future__ import annotations
+
+from datetime import datetime
+from uuid import UUID
+
+from fastapi import APIRouter, Depends, HTTPException, Query
+from sqlmodel import col, select
+from sqlmodel.ext.asyncio.session import AsyncSession
+
+from app.api.deps import OrganizationContext, require_org_member
+from app.core.logging import get_logger
+from app.db import pagination
+from app.db.session import get_session
+from app.models.monitoring import (
+    CostSnapshot,
+    CronJobStatus,
+    SessionEvent,
+    SubAgentRun,
+    SystemHealthMetric,
+)
+from app.schemas.monitoring import (
+    CostSnapshotRead,
+    CronJobStatusRead,
+    SessionEventRead,
+    SubAgentRunRead,
+    SystemHealthMetricRead,
+)
+from app.schemas.pagination import DefaultLimitOffsetPage
+
+router = APIRouter(prefix="/monitoring", tags=["monitoring"])
+SESSION_DEP = Depends(get_session)
+ORG_MEMBER_DEP = Depends(require_org_member)
+
+_logger = get_logger(__name__)
+
+# Query parameter constants
+GATEWAY_ID_QUERY = Query(default=None, description="Filter by gateway ID")
+JOB_NAME_QUERY = Query(default=None, description="Filter by job name")
+ENABLED_QUERY = Query(default=None, description="Filter by enabled status")
+SESSION_KEY_QUERY = Query(default=None, description="Filter by session key")
+MODEL_QUERY = Query(default=None, description="Filter by model name")
+EVENT_TYPE_QUERY = Query(default=None, description="Filter by event type")
+STATUS_QUERY = Query(default=None, description="Filter by status")
+AGENT_QUERY = Query(default=None, description="Filter by agent name")
+START_DATE_QUERY = Query(default=None, description="Filter from this date (inclusive)")
+END_DATE_QUERY = Query(default=None, description="Filter until this date (inclusive)")
+
+
+@router.get(
+    "/cost-snapshots",
+    response_model=DefaultLimitOffsetPage[CostSnapshotRead],
+    summary="List Cost Snapshots",
+    description="List cost snapshots for gateways in the caller's organization.",
+)
+async def list_cost_snapshots(
+    gateway_id: UUID | None = GATEWAY_ID_QUERY,
+    start: datetime | None = START_DATE_QUERY,
+    end: datetime | None = END_DATE_QUERY,
+    session: AsyncSession = SESSION_DEP,
+    ctx: OrganizationContext = ORG_MEMBER_DEP,
+) -> DefaultLimitOffsetPage[CostSnapshotRead]:
+    """List cost snapshots with optional filters.
+
+    - **gateway_id**: Filter by specific gateway
+    - **start**: Filter snapshots from this date (inclusive)
+    - **end**: Filter snapshots until this date (inclusive)
+    """
+    statement = select(CostSnapshot).where(
+        CostSnapshot.organization_id == ctx.organization.id
+    )
+
+    if gateway_id is not None:
+        statement = statement.where(CostSnapshot.gateway_id == gateway_id)
+
+    if start is not None:
+        statement = statement.where(CostSnapshot.collected_at >= start)
+
+    if end is not None:
+        statement = statement.where(CostSnapshot.collected_at <= end)
+
+    statement = statement.order_by(col(CostSnapshot.created_at).desc())
+    return await pagination.paginate(session, statement)
+
+
+@router.get(
+    "/cost-snapshots/{id}",
+    response_model=CostSnapshotRead,
+    summary="Get Cost Snapshot",
+    description="Get a single cost snapshot by ID.",
+)
+async def get_cost_snapshot(
+    id: UUID,
+    session: AsyncSession = SESSION_DEP,
+    ctx: OrganizationContext = ORG_MEMBER_DEP,
+) -> CostSnapshot:
+    """Get a cost snapshot by ID."""
+    snapshot = await CostSnapshot.objects.by_id(id).first(session)
+    if snapshot is None:
+        raise HTTPException(status_code=404, detail="Cost snapshot not found")
+    if snapshot.organization_id != ctx.organization.id:
+        raise HTTPException(status_code=403, detail="Access denied")
+    return snapshot
+
+
+@router.get(
+    "/cron-jobs",
+    response_model=DefaultLimitOffsetPage[CronJobStatusRead],
+    summary="List Cron Job Statuses",
+    description="List cron job statuses for gateways in the caller's organization.",
+)
+async def list_cron_jobs(
+    gateway_id: UUID | None = GATEWAY_ID_QUERY,
+    enabled: bool | None = ENABLED_QUERY,
+    job_name: str | None = JOB_NAME_QUERY,
+    session: AsyncSession = SESSION_DEP,
+    ctx: OrganizationContext = ORG_MEMBER_DEP,
+) -> DefaultLimitOffsetPage[CronJobStatusRead]:
+    """List cron job statuses with optional filters.
+
+    - **gateway_id**: Filter by specific gateway
+    - **enabled**: Filter by enabled status
+    - **job_name**: Filter by job name (exact match)
+    """
+    statement = select(CronJobStatus).where(
+        CronJobStatus.organization_id == ctx.organization.id
+    )
+
+    if gateway_id is not None:
+        statement = statement.where(CronJobStatus.gateway_id == gateway_id)
+
+    if enabled is not None:
+        statement = statement.where(CronJobStatus.enabled == enabled)
+
+    if job_name is not None:
+        statement = statement.where(CronJobStatus.job_name == job_name)
+
+    statement = statement.order_by(col(CronJobStatus.created_at).desc())
+    return await pagination.paginate(session, statement)
+
+
+@router.get(
+    "/cron-jobs/{id}",
+    response_model=CronJobStatusRead,
+    summary="Get Cron Job Status",
+    description="Get a single cron job status by ID.",
+)
+async def get_cron_job(
+    id: UUID,
+    session: AsyncSession = SESSION_DEP,
+    ctx: OrganizationContext = ORG_MEMBER_DEP,
+) -> CronJobStatus:
+    """Get a cron job status by ID."""
+    job = await CronJobStatus.objects.by_id(id).first(session)
+    if job is None:
+        raise HTTPException(status_code=404, detail="Cron job status not found")
+    if job.organization_id != ctx.organization.id:
+        raise HTTPException(status_code=403, detail="Access denied")
+    return job
+
+
+@router.get(
+    "/sessions",
+    response_model=DefaultLimitOffsetPage[SessionEventRead],
+    summary="List Session Events",
+    description="List session events for gateways in the caller's organization.",
+)
+async def list_sessions(
+    gateway_id: UUID | None = GATEWAY_ID_QUERY,
+    session_key: str | None = SESSION_KEY_QUERY,
+    model: str | None = MODEL_QUERY,
+    event_type: str | None = EVENT_TYPE_QUERY,
+    session: AsyncSession = SESSION_DEP,
+    ctx: OrganizationContext = ORG_MEMBER_DEP,
+) -> DefaultLimitOffsetPage[SessionEventRead]:
+    """List session events with optional filters.
+
+    - **gateway_id**: Filter by specific gateway
+    - **session_key**: Filter by session key
+    - **model**: Filter by model name
+    - **event_type**: Filter by event type
+    """
+    statement = select(SessionEvent).where(
+        SessionEvent.organization_id == ctx.organization.id
+    )
+
+    if gateway_id is not None:
+        statement = statement.where(SessionEvent.gateway_id == gateway_id)
+
+    if session_key is not None:
+        statement = statement.where(SessionEvent.session_key == session_key)
+
+    if model is not None:
+        statement = statement.where(SessionEvent.model == model)
+
+    if event_type is not None:
+        statement = statement.where(SessionEvent.event_type == event_type)
+
+    statement = statement.order_by(col(SessionEvent.created_at).desc())
+    return await pagination.paginate(session, statement)
+
+
+@router.get(
+    "/sessions/{id}",
+    response_model=SessionEventRead,
+    summary="Get Session Event",
+    description="Get a single session event by ID.",
+)
+async def get_session_event(
+    id: UUID,
+    session: AsyncSession = SESSION_DEP,
+    ctx: OrganizationContext = ORG_MEMBER_DEP,
+) -> SessionEvent:
+    """Get a session event by ID."""
+    event = await SessionEvent.objects.by_id(id).first(session)
+    if event is None:
+        raise HTTPException(status_code=404, detail="Session event not found")
+    if event.organization_id != ctx.organization.id:
+        raise HTTPException(status_code=403, detail="Access denied")
+    return event
+
+
+@router.get(
+    "/health",
+    response_model=DefaultLimitOffsetPage[SystemHealthMetricRead],
+    summary="List System Health Metrics",
+    description="List system health metrics for gateways in the caller's organization.",
+)
+async def list_health_metrics(
+    gateway_id: UUID | None = GATEWAY_ID_QUERY,
+    start: datetime | None = START_DATE_QUERY,
+    end: datetime | None = END_DATE_QUERY,
+    session: AsyncSession = SESSION_DEP,
+    ctx: OrganizationContext = ORG_MEMBER_DEP,
+) -> DefaultLimitOffsetPage[SystemHealthMetricRead]:
+    """List system health metrics with optional filters.
+
+    - **gateway_id**: Filter by specific gateway
+    - **start**: Filter metrics from this date (inclusive)
+    - **end**: Filter metrics until this date (inclusive)
+    """
+    statement = select(SystemHealthMetric).where(
+        SystemHealthMetric.organization_id == ctx.organization.id
+    )
+
+    if gateway_id is not None:
+        statement = statement.where(SystemHealthMetric.gateway_id == gateway_id)
+
+    if start is not None:
+        statement = statement.where(SystemHealthMetric.collected_at >= start)
+
+    if end is not None:
+        statement = statement.where(SystemHealthMetric.collected_at <= end)
+
+    statement = statement.order_by(col(SystemHealthMetric.created_at).desc())
+    return await pagination.paginate(session, statement)
+
+
+@router.get(
+    "/health/{id}",
+    response_model=SystemHealthMetricRead,
+    summary="Get System Health Metric",
+    description="Get a single system health metric by ID.",
+)
+async def get_health_metric(
+    id: UUID,
+    session: AsyncSession = SESSION_DEP,
+    ctx: OrganizationContext = ORG_MEMBER_DEP,
+) -> SystemHealthMetric:
+    """Get a system health metric by ID."""
+    metric = await SystemHealthMetric.objects.by_id(id).first(session)
+    if metric is None:
+        raise HTTPException(status_code=404, detail="Health metric not found")
+    if metric.organization_id != ctx.organization.id:
+        raise HTTPException(status_code=403, detail="Access denied")
+    return metric
+
+
+@router.get(
+    "/sub-agents",
+    response_model=DefaultLimitOffsetPage[SubAgentRunRead],
+    summary="List Sub-Agent Runs",
+    description="List sub-agent runs for gateways in the caller's organization.",
+)
+async def list_sub_agents(
+    gateway_id: UUID | None = GATEWAY_ID_QUERY,
+    status: str | None = STATUS_QUERY,
+    agent: str | None = AGENT_QUERY,
+    session: AsyncSession = SESSION_DEP,
+    ctx: OrganizationContext = ORG_MEMBER_DEP,
+) -> DefaultLimitOffsetPage[SubAgentRunRead]:
+    """List sub-agent runs with optional filters.
+
+    - **gateway_id**: Filter by specific gateway
+    - **status**: Filter by run status (pending, running, succeeded, failed)
+    - **agent**: Filter by agent name
+    """
+    statement = select(SubAgentRun).where(
+        SubAgentRun.organization_id == ctx.organization.id
+    )
+
+    if gateway_id is not None:
+        statement = statement.where(SubAgentRun.gateway_id == gateway_id)
+
+    if status is not None:
+        statement = statement.where(SubAgentRun.status == status)
+
+    if agent is not None:
+        statement = statement.where(SubAgentRun.agent == agent)
+
+    statement = statement.order_by(col(SubAgentRun.created_at).desc())
+    return await pagination.paginate(session, statement)
+
+
+@router.get(
+    "/sub-agents/{id}",
+    response_model=SubAgentRunRead,
+    summary="Get Sub-Agent Run",
+    description="Get a single sub-agent run by ID.",
+)
+async def get_sub_agent_run(
+    id: UUID,
+    session: AsyncSession = SESSION_DEP,
+    ctx: OrganizationContext = ORG_MEMBER_DEP,
+) -> SubAgentRun:
+    """Get a sub-agent run by ID."""
+    run = await SubAgentRun.objects.by_id(id).first(session)
+    if run is None:
+        raise HTTPException(status_code=404, detail="Sub-agent run not found")
+    if run.organization_id != ctx.organization.id:
+        raise HTTPException(status_code=403, detail="Access denied")
+    return run
diff --git a/src/backend/app/main.py b/src/backend/app/main.py
index 0a3bd33..ddb3f0e 100644
--- a/src/backend/app/main.py
+++ b/src/backend/app/main.py
@@ -25,6 +25,7 @@ from app.api.boards import router as boards_router
 from app.api.gateway import router as gateway_router
 from app.api.gateways import router as gateways_router
 from app.api.metrics import router as metrics_router
+from app.api.monitoring import router as monitoring_router
 from app.api.organizations import router as organizations_router
 from app.api.skills_marketplace import router as skills_marketplace_router
 from app.api.souls_directory import router as souls_directory_router
@@ -582,6 +583,7 @@ api_v1.include_router(activity_router)
 api_v1.include_router(gateway_router)
 api_v1.include_router(gateways_router)
 api_v1.include_router(metrics_router)
+api_v1.include_router(monitoring_router)
 api_v1.include_router(organizations_router)
 api_v1.include_router(souls_directory_router)
 api_v1.include_router(skills_marketplace_router)
diff --git a/src/backend/app/schemas/__init__.py b/src/backend/app/schemas/__init__.py
index 163e258..99b9129 100644
--- a/src/backend/app/schemas/__init__.py
+++ b/src/backend/app/schemas/__init__.py
@@ -21,6 +21,13 @@ from app.schemas.board_webhooks import (
 from app.schemas.boards import BoardCreate, BoardRead, BoardUpdate
 from app.schemas.gateways import GatewayCreate, GatewayRead, GatewayUpdate
 from app.schemas.metrics import DashboardMetrics
+from app.schemas.monitoring import (
+    CostSnapshotRead,
+    CronJobStatusRead,
+    SessionEventRead,
+    SubAgentRunRead,
+    SystemHealthMetricRead,
+)
 from app.schemas.organizations import (
     OrganizationActiveUpdate,
     OrganizationCreate,
@@ -79,6 +86,11 @@ __all__ = [
     "GatewayRead",
     "GatewayUpdate",
     "DashboardMetrics",
+    "CostSnapshotRead",
+    "CronJobStatusRead",
+    "SessionEventRead",
+    "SubAgentRunRead",
+    "SystemHealthMetricRead",
     "OrganizationActiveUpdate",
     "OrganizationCreate",
     "OrganizationInviteAccept",
diff --git a/src/backend/app/schemas/monitoring.py b/src/backend/app/schemas/monitoring.py
new file mode 100644
index 0000000..405ca65
--- /dev/null
+++ b/src/backend/app/schemas/monitoring.py
@@ -0,0 +1,113 @@
+"""Monitoring schemas for Mission Control API."""
+
+from __future__ import annotations
+
+from datetime import datetime
+from uuid import UUID
+
+from sqlmodel import SQLModel
+
+from app.schemas.pagination import DefaultLimitOffsetPage
+
+
+class CostSnapshotRead(SQLModel):
+    """Cost snapshot read payload."""
+
+    id: UUID
+    organization_id: UUID
+    gateway_id: UUID
+    period_start: datetime
+    period_end: datetime
+    total_cost: float
+    model_costs: dict | None = None
+    provider_costs: dict | None = None
+    token_counts: dict | None = None
+    collected_at: datetime
+    created_at: datetime
+    updated_at: datetime
+
+
+class CronJobStatusRead(SQLModel):
+    """Cron job status read payload."""
+
+    id: UUID
+    organization_id: UUID
+    gateway_id: UUID
+    job_name: str
+    schedule: str
+    enabled: bool
+    last_run_at: datetime | None = None
+    next_run_at: datetime | None = None
+    status: str
+    failure_count: int
+    last_error: str | None = None
+    metadata_: dict | None = None
+    created_at: datetime
+    updated_at: datetime
+
+
+class SessionEventRead(SQLModel):
+    """Session event read payload."""
+
+    id: UUID
+    organization_id: UUID
+    gateway_id: UUID
+    session_key: str
+    event_type: str
+    model: str | None = None
+    agent_id: str | None = None
+    channel: str | None = None
+    context_percent: float | None = None
+    token_counts: dict | None = None
+    cost: float | None = None
+    metadata_: dict | None = None
+    created_at: datetime
+    updated_at: datetime
+
+
+class SubAgentRunRead(SQLModel):
+    """Sub-agent run read payload."""
+
+    id: UUID
+    organization_id: UUID
+    gateway_id: UUID
+    parent_session_key: str
+    session_event_id: UUID | None = None
+    agent: str | None = None
+    model: str | None = None
+    status: str
+    duration_ms: int | None = None
+    cost: float | None = None
+    token_counts: dict | None = None
+    metadata_: dict | None = None
+    created_at: datetime
+    updated_at: datetime
+
+
+class SystemHealthMetricRead(SQLModel):
+    """System health metric read payload."""
+
+    id: UUID
+    organization_id: UUID
+    gateway_id: UUID
+    cpu_percent: float | None = None
+    cpu_cores: int | None = None
+    ram_used_bytes: int | None = None
+    ram_total_bytes: int | None = None
+    ram_percent: float | None = None
+    swap_used_bytes: int | None = None
+    swap_total_bytes: int | None = None
+    swap_percent: float | None = None
+    disk_path: str
+    disk_used_bytes: int | None = None
+    disk_total_bytes: int | None = None
+    disk_percent: float | None = None
+    gateway_live: bool | None = None
+    gateway_ready: bool | None = None
+    gateway_uptime_ms: int | None = None
+    gateway_pid: int | None = None
+    gateway_version: str | None = None
+    metadata_: dict | None = None
+    collected_at: datetime
+    created_at: datetime
+    updated_at: datetime