Migrating from IBM API Connect v5 (SaaS) to API Connect Microgateway

The Tech May Be Old, The Takeaways Aren't

API Connect v5 (SaaS) to the IBM Microgateway (OSS) — And What It Taught Us.
~Shahbaz Ali

1. Introduction

This was the early era of API management solutions. Looking back now, both platforms — API Connect v5 and the open-source microgateway we moved to — are deprecated, out of support, and no longer in active use by anyone. But at that time, this was new territory for us: a new stack, and a new set of challenges we hadn't faced before.

2. Context

Let's first talk about why did we chose to go with SaaS because of no maintenance, easy and quick upgrades, zero downtime, and 100% support, Overtime we decided to switch back to on-prem due to network latency increased as the cloud was outside our region, and hard dependencies on integrations — there were some backend and third-party systems that required dedicated VPN tunnels, etc. We also needed a custom developer portal — something out-of-the-box with Angular/React — instead of Drupal.

3. Why we chose IBM Microgateway

This was the core idea behind going with the IBM Microgateway: it was Node.js-based and open-source, built on the same underlying structure API Connect itself originated from. It wasn't mature enough at the time, but it was still the ideal solution for us what we needed.

The main reason was to do a big-bang migration where no consumer would be affected. All the client keys, etc., could simply be exported and imported as-is — the only change needed was a DNS switch.

Here is the old version of IBM microgateway: https://github.com/strongloop/microgateway

4. Target Architecture

5. Migration Approach & Strategy

We started with an assessment covering API inventory, dependency mapping, and traffic analysis. Given our goal of zero consumer impact, we went with a big-bang theory migration — all client keys and subscriptions were imported directly into the new platform, so no re-onboarding was needed. We used [scripts/CI-CD tooling] to automate the policy translation from API Connect v5 to microgateway equivalents, then validated everything through functional, load, and security testing before cutover. The switch itself was a simple DNS change — no canary or blue-green rollout required, since the new environment was already fully mirrored and validated beforehand.

6. Challenges Faced

Technical: Reaching full policy parity between API Connect v5 and the microgateway took real effort — some policies didn't have a direct one-to-one equivalent and needed custom extensions to replicate the original behavior. Protocol and cipher support turned out to be a bigger gap than expected, which is exactly what caused our failed go-live attempts — certificate and cipher mismatches that hadn't surfaced during earlier testing. Monitoring and observability also needed to be rebuilt almost from scratch, since the SaaS platform's built-in dashboards and alerting didn't carry over to the new self-managed environment.

Organizational: Moving from a fully managed SaaS platform to something we owned end-to-end meant a real skill gap for the team — new tooling, new operational responsibilities, and a different mental model for how the platform behaved. Change management mattered more than expected too: stakeholders were used to zero-touch upgrades and had to be brought along on why a big-bang cutover, with the possibility of a failed first attempt, was still the right approach. Getting buy-in for that risk upfront made the actual failed attempts far less stressful when they happened.

Operational: Because this was a big-bang migration, we didn't have the luxury of a gradual downtime window — any issue at go-live was immediately production-facing. SLA pressure was real, given the criticality of the APIs involved. What ultimately saved us was rollback planning done properly ahead of time: DNS could be reverted back to the old platform within seconds, which is exactly what let us fail twice, recover cleanly both times, and try again without any lasting consumer impact.

8. Risks & Mitigations

9. Lessons Learned

• Rollback design is as important as cutover design: The ability to revert DNS in seconds turned what could have been catastrophic go-live failures into manageable operational blips. If you are executing a big-bang migration, your safety net must be instant, proven, and zero-touch.
• Pre-production tests rarely catch real-world cases: Similar mismatches in ciphers, legacy protocols, and mutual TLS certificates are notoriously hard to simulate in staging. Modern migration checklists need deep, production-like SSL/TLS validation and payload inspection long before DNS changes happen.
• Open source offers flexibility, but shifts the operational burden entirely to you: Moving away from SaaS gave us freedom, local low-latency routing, and custom portal flexibility, but it required us to build our own observability, security extensions, and maintenance pipelines from scratch.
• Stakeholder transparency mitigates cutover anxiety: Getting upfront alignment on the risk profile of a big-bang migration changed how failure was perceived. Because leadership knew a DNS rollback was guaranteed, two failed go-live attempts were treated as learning iterations rather than operational disasters.
• Migration windows require strict freeze discipline: Trying to hit a moving target is a recipe for failure. Freezing non-critical API feature updates during the cutover window minimized variables and let us focus purely on policy parity and platform stability.

10. Final Thoughts

Looking back, the technologies we relied on for this migration have long since been retired or superseded by modern service meshes and cloud-native gateways. However, the core engineering discipline remains unchanged. Choosing the right architectural trade-offs—balancing SaaS convenience against local latency and custom integration needs—is a challenge engineering teams still face today. Tools will always evolve and deprecate, but the principles of resilient migration design, clear rollback strategies, and upfront risk management never go out of style.

Here is my blog series link:
https://lnkd.in/p/dZwzq27P

https://community.ibm.com/community/user/blogs/shahbaz-ali/2026/08/09/migration-from-iib-v10-to-cp4i-app-connect