Here’s a directional sort of the segments I listed earlier, using a simple, defensible heuristic:
Revenue size bucket (global spend / vendor revenue pool): Mega (>$10B), Large ($1–10B), Mid ($100M–$1B), Emerging (<$100M)
Recent YoY growth band: Hyper (>100%), Fast (50–100%), Solid (20–50%), Early/Choppy (<20% or too new)
I’m not claiming precise market sizes for each niche (most are privately held + definitions vary). This is a logical estimate anchored to public signals like: Nvidia’s AI data center revenue growth (proxy for compute), application-layer spend estimates, and evidence of multiple vendors hitting $100M+ ARR in specific app categories. (NVIDIA Newsroom)
Tier 1 — Biggest revenue pools and still growing fast
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AI compute stack (GPUs + data center buildout + GPU cloud)
Size: Mega
YoY: Fast–Hyper (compute expansion + vendor revenue growth signals)
Anchor: Nvidia reported data center revenue up 66% YoY (quarterly). (NVIDIA Newsroom)
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Application layer: horizontal copilots + vertical copilots + departmental AI (incl. coding assistants)
Size: Large–Mega
YoY: Fast
Anchor: GenAI enterprise spend shows the application layer at ~$19B in 2025 (one estimate). (Menlo Ventures)
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Customer service AI agents (chat + call center automation/agent assist)
Size: Large (already real budgets; clear ROI)
YoY: Hyper in many vendors (category “exploded” + multiple $100M+ ARR vendors) (CB Insights)
Tier 2 — Large pools forming quickly (high growth, moving into “standard budget lines”)
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Inference optimization + serving infrastructure (latency/cost killers)
Size: Large
YoY: Fast
Why: inference costs are now a board-level line item as usage scales (e.g., OpenAI revenue scaling implies huge inference volume). (Reuters)
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“Agents platform” / orchestration layer (tool-use, routing, workflow automation)
Size: Mid → Large
YoY: Fast–Hyper (many pilots → production)
Anchor signals: enterprise vendors emphasizing agents/workflow automation; partnerships embedding agents in business software. (Reuters)
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Enterprise search reborn as “answer engines” (knowledge worker productivity)
Size: Mid → Large
YoY: Fast
Why: it’s the first stop for “safe” internal rollout (doc Q&A + citations).
Tier 3 — Solid, durable “picks-and-shovels” (big enough; growth steady)
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Vector databases / vector search services
Size: Mid → Large (depending on what you include)
YoY: Solid–Fast
Note: analyst estimates vary wildly; treat as direction-only. (SNS Insider)
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RAG tooling + retrieval pipelines (chunking/indexing/rerank/hybrid search)
Size: Mid
YoY: Solid–Fast
Why: nearly every enterprise build touches RAG, so tooling gets pulled along.
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LLM observability (tracing, cost, eval regressions, incident debugging)
Size: Mid
YoY: Fast
Anchor (adoption signal): analyses of many production deployments emphasize context engineering/guardrails/discipline (which drives observability demand). (zenml.io)
Evaluation-as-a-service (Evals) + synthetic data for evals
Size: Emerging → Mid
YoY: Fast
Why: once teams ship, they need CI-like regression tests.
Tier 4 — Smaller today, very high growth, “new interface” bets
Realtime voice agents / multimodal (speech-in, speech-out)
Size: Mid (but fragmented)
YoY: Fast–Hyper (voice is becoming a primary interface)
Anchors: major platform support for realtime + talent/tech acquisitions around voice; vendor claims vary. (Menlo Ventures)
Edge/on-device LLM serving
Size: Emerging → Mid
YoY: Fast
Why: privacy + latency + cost pressure push smaller models locally.
Tier 5 — Compliance/security/governance: smaller pools but becoming mandatory
AI governance platforms (inventory, approvals, audit trails, policy enforcement)
Size: Emerging → Mid
YoY: Fast
Driver: regulation + procurement requirements.
Prompt-injection / agent security tooling
Size: Emerging
YoY: Hyper (new attack surface appears as tool-use/agents spread) (zenml.io)
ISO/IEC 42001 “AIMS” certification + consulting ecosystem
Size: Emerging → Mid
YoY: Solid–Fast (services-led growth; standards-driven) (zenml.io)
Tier 6 — “Nice-to-have” or cyclic segments (still real, but less consistently explosive)
Marketing content supply chain (generation + approvals + brand safety)
Size: Mid
YoY: Solid (some saturation; lots of competition)
Translation/localization at scale (LLM-assisted workflows)
Size: Mid
YoY: Solid (strong but more mature)
Fine-tuning/distillation service providers
Size: Mid
YoY: Choppy (waves: hype → platform improvements → renewed demand)
Licensed-data packaging for LLMs (entitlements, audit, “LLM-ready” feeds)
Size: Emerging → Mid
YoY: Solid–Fast (enterprise deals take time)
Connector standards / tool servers (e.g., MCP ecosystem)
Size: Emerging
YoY: Hyper (early)
Anchor: MCP momentum as a standard for tool/data connections. (zenml.io)
If you want this more quantitative, tell me which definition you care about:
(A) total end-customer spend (“market size”), or
(B) vendor revenue pool (ARR), or
(C) growth in deployments/adoption (logos / usage),
…and I’ll re-rank with explicit % ranges per segment (still estimates, but tighter and more consistent).