The Evolution of Instant Messaging Systems Over the Past Fifteen Years and the Rise of Cloud‑Native IM

Technology changes over time, so even identical scenarios and requirements can be addressed with completely different solutions in each era.

As user expectations and labor costs rise, building an industry‑standard instant‑messaging (IM) system becomes increasingly difficult, yet the decision to build one from scratch still depends on many factors.

This article reviews the three development stages of IM software over the past fifteen years, explains the reasoning behind system selection, and introduces the new generation of cloud‑native IM.

Recently, the legacy service Feixin was shut down, prompting reflections on the evolution of IM. Feixin, launched in 2007, grew rapidly because early internet infrastructure favored low‑bandwidth, high‑cost networks, making its SMS‑integrated messaging uniquely timely.

However, as network speeds improved and fees dropped, Feixin’s advantage vanished, and the rise of mobile internet ended its opportunity.

Like many developers, I have been working on IM since 2007, witnessing countless app integrations and the recurring challenges of IM development.

Is IM just chat? Has the technology matured? This article focuses on the technical problem of building an IM system rather than product features.

Over the past fifteen years, IM technology has roughly passed through three phases.

Phase 1: Software and High‑Concurrency Services In the early internet era, building a system required purchasing hardware and renting server racks. Without cloud services or ready‑made SDKs, developers started from open‑source protocols and software. The PC‑internet era favored stable, slower networks; standards like XMPP (2000) became common. High concurrency challenges (C10K, C100K, C1000K) drove advances in thread pools and I/O models (epoll, select). Most IM services were built from scratch, leading to long, inefficient development cycles.

Phase 2: Mobile Internet and Cloud The 2009 rollout of 3G and the launch of the iPhone 3GS created a mobile‑internet boom. Mobile networks introduced frequent disconnections, making traditional XMPP inefficient in bandwidth and power consumption. Companies adopted binary protocols, explicit ACK mechanisms, and unified online/offline storage to ensure reliable delivery. The market saw the emergence of IM cloud services (2014) offering SDKs and APIs, allowing app developers to integrate messaging quickly. Developers split into three groups: ordinary app developers using SDKs, cloud‑service providers building cross‑platform back‑ends, and enterprises that still built their own systems for security or policy reasons.

Live‑streaming and ultra‑large group chats (e.g., 10 000‑person rooms) introduced new scaling challenges: message distribution must be sharded across queues and servers, group‑member lists must be stored in memory with sharding, and priority‑based message dropping becomes necessary.

Phase 3: Cloud‑Native With the rise of Kubernetes (v1.0, 2015) and the Cloud Native Computing Foundation, IM services began adopting cloud‑native architectures. Multi‑cloud support requires unified interfaces and management consoles, while multi‑cluster deployments must handle unstable public‑network links. IM systems need causal consistency rather than eventual consistency, focusing on per‑conversation ordering. ID generation can use Snowflake‑style algorithms to ensure globally unique, roughly time‑ordered identifiers.

Automation of installation, licensing, CI/CD pipelines, and configuration‑as‑a‑service enable rapid private‑cloud deployments—often within ten minutes. Cloud‑native IM reduces costs by two orders of magnitude compared with traditional private deployments.

In summary, the evolution of IM mirrors broader software trends: from monolithic, self‑built solutions to cloud‑based SDKs, and finally to cloud‑native services that unify public and private deployments.

Postscript The author believes most software follows a similar trajectory; using IM as an example hopes to inspire developers. References to Marc Andreessen’s “software is eating the world” and the ongoing shift between on‑premise and cloud solutions illustrate this transformation.

About Blue‑Swan IM : a new cloud‑native IM platform offering professional SDKs and monthly‑pay private‑cloud options, with plans to open its framework as a universal cloud‑native communication layer.

For more on Blue‑Swan IM, see the linked article “In Africa, one in two smartphones will use Blue‑Swan IM”.