Below is a practical, vendor-neutral guide to enterprise integration tools you can use to connect cloud and on‑prem systems — plus key capabilities, example products (cloud and on‑prem/hybrid), selection criteria, and deployment/architecture tips.

1. What enterprise integration tools do (core capabilities)

• Connectors/adapters for SaaS, databases, legacy apps, message queues, files, APIs.
• API management and gateway features (expose, secure, version APIs).
• Data mapping, transformation, orchestration and workflow/rules engines.
• Event streaming / pub-sub and message mediation (guaranteed delivery, retries).
• B2B/EDI support, protocol bridging (SOAP/REST/JDBC/FTP/JMS/etc.).
• Monitoring, logging, tracing, SLA/health dashboards, alerting.
• Security: authn/authz, encryption, tenant isolation, compliance features.
• Deployment flexibility: cloud-native (SaaS/PaaS), on‑premises, or hybrid.

2. Categories of tools

• iPaaS (Integration Platform as a Service): multi-tenant cloud integration, fast SaaS-to-SaaS and cloud-to-onprem connectors.
• ESB / Integration Middleware: heavyweight messaging/mediations for on‑prem and hybrid enterprise landscapes.
• API Management + Gateways: exposing and managing APIs plus developer portals and rate-limiting.
• Event streaming platforms: high-throughput pub/sub for real-time pipelines.
• Lightweight integration frameworks/libraries: for bespoke integrations embedded in apps (useful where full platform is overkill).
• Managed ETL/ELT data-integration and data-pipeline platforms: for analytic workloads.

3. Widely used products (representative list; not exhaustive)

• iPaaS / Cloud-first

  • MuleSoft Anypoint Platform — strong API management + connectors, popular in enterprises.
  • Dell Boomi — cloud-native iPaaS, fast connector library and visual mapping.
  • Informatica Intelligent Cloud Services — broad data/integration and governance capabilities.
  • SnapLogic — visual pipelines, elastic cloud runtime.
  • Workato — automation + integration with many SaaS connectors (often used for line-of-business automations).

• Cloud vendor native services

  • AWS: API Gateway, AWS AppFlow, Step Functions, EventBridge, Glue, Managed Workflows (good for AWS-centric stacks).
  • Azure: Logic Apps, Service Bus, API Management, Data Factory (good for Microsoft-centric stacks).
  • Google Cloud: Apigee (API management), Cloud Pub/Sub, Dataflow, Workflows.

• Traditional ESB / Hybrid

  • IBM App Connect / IBM Integration Bus — enterprise-grade hybrid integration and message mediation.
  • TIBCO (e.g., TIBCO Cloud Integration, TIBCO EMS) — strong in event/messaging and transactional integration.
  • Software AG (webMethods) — integration + B2B/EDI capabilities.
  • Oracle Integration Cloud / Oracle SOA Suite — enterprise integrations, especially in Oracle environments.
  • SAP Integration Suite — for SAP landscapes, S/4HANA and hybrid SAP/non-SAP integration.

• Event streaming / messaging platforms

  • Apache Kafka (Confluent for enterprise features) — high-throughput event streaming and durable logs.
  • RabbitMQ / ActiveMQ — robust message queuing for transactional workloads.

• Open-source / lightweight frameworks

  • Apache Camel — routing and mediation DSL for embedding integrations.
  • WSO2 Enterprise Integrator — API, ESB, enterprise features with open-source roots.
  • NServiceBus / MassTransit — .NET-focused messaging frameworks.

4. How to choose (key selection criteria)

• Integration scenarios: point-to-point SaaS sync vs complex orchestration vs high-volume streaming analytics.
• Connector ecosystem: does it have prebuilt connectors for your critical SaaS, databases, SAP, mainframe?
• Hybrid support: ability to run runtime agents on‑premise behind firewall and connect securely to cloud control plane.
• Throughput, latency, and delivery semantics: batch ETL vs real-time vs guaranteed once-only delivery.
• API-first and developer experience: design, test, publish APIs, version control, CI/CD support.
• Security & compliance: encryption at rest/in transit, IAM integration (OAuth, SAML, LDAP), certifications (SOC2, ISO, PCI, HIPAA if needed).
• Monitoring & observability: tracing/spans, metrics, logging, SLA dashboards, alerting integrations.
• Scaling & high availability: autoscaling, clustering, multi‑region support.
• Total cost of ownership: licensing, runtime nodes, connectors cost, support and implementation services.
• Vendor lock-in risk vs extensibility: open standards and ability to export flows, run locally.
• Team skills: Java/Node/.NET experience, willingness to manage infra vs prefer SaaS.

5. Recommended architectures for hybrid (cloud + on‑prem)

• Use a lightweight on‑prem runtime/agent for secure access: control plane in cloud, secure tunnels or outbound-only connectors from on‑prem to cloud (no inbound firewall holes).
• API gateway at the perimeter (cloud or on‑prem) for uniform security/observability.
• Separate data pipelines: use ETL/ELT or streaming for analytics (e.g., change-data-capture -> Kafka -> cloud data lake).
• Event-driven for real-time: EventBridge/Kafka between systems; use connectors to mirror events across cloud/on‑prem.
• Use message queue/ESB for transactional, guaranteed-delivery interactions; use iPaaS for SaaS connectivity and faster integration dev.

6. Operational concerns and best practices

• Secure credential storage and secrets management (vaults, KMS).
• Automate deployments: CI/CD for integration flows, version control for mappings and APIs.
• End-to-end tracing and correlation IDs across services.
• Standardize error handling and retry policies.
• Govern connectors and APIs centrally; enforce naming/versioning, SLAs, quotas.
• Start with critical use-cases: map business priority, then pilot one domain before wide rollout.

7. Quick recommendations by use-case

• Fast SaaS-to-SaaS or cloud-to-onprem with low ops overhead: Dell Boomi, MuleSoft (SaaS mode), Workato.
• API-first enterprise with strong developer needs: MuleSoft Anypoint, Apigee, Azure API Management.
• High-throughput real-time streaming (events/analytics): Apache Kafka / Confluent.
• SAP and ERP-heavy landscapes: SAP Integration Suite or webMethods.
• On‑prem heavy, transaction oriented: IBM App Connect, TIBCO, Oracle SOA.
• Cost-sensitive / open-source preference: Apache Camel, WSO2, self-managed Kafka.

8. Next practical steps (how to evaluate)

• List the top 8–12 systems you must integrate, expected volumes, latency needs, and security requirements.
• Shortlist 3 vendors/frameworks matching your environment (cloud provider alignment, SAP/Oracle dependence, developer skillset).
• Run a 4–8 week proof-of-concept: implement 2 representative integration scenarios (one transactional, one high-throughput or SaaS sync).
• Evaluate runtimes, deployment model, ops experience, and total cost including connectors and support.
• Define governance (who owns integrations, CI/CD, monitoring, SLAs).

If you want, I can:

• Produce a two-page RFP checklist tailored to your environment (include connector list, throughput, security/compliance items), or
• Shortlist 3 tools for your specific stack — tell me the core systems (ERP, CRM, cloud provider, messaging) and preferred constraints (budget, managed vs self‑hosted).