CorpusIQ collapses 36 business APIs into one MCP endpoint

CorpusIQ's post describes the architecture behind a unified MCP endpoint designed to solve "API sprawl" for business operators. The team identified 36 APIs that a typical SaaS operator touches weekly — Stripe, HubSpot, Google Analytics, QuickBooks, Slack, GitHub, and others — each with its own authentication mechanism, data format, pagination pattern, and rate limit behavior. Rather than exposing 36 separate MCP tools, CorpusIQ exposes a single query tool with a unified schema, routing natural-language business questions to the appropriate underlying APIs and returning clean, structured data.

First, the system is strictly read-only by design, eliminating any risk of an agent triggering destructive operations.

Three architectural decisions stand out. First, the system is strictly read-only by design, eliminating any risk of an agent triggering destructive operations. Second, authentication uses the OAuth 2.0 Device Authorization Grant — the same flow used by streaming devices — so no passwords or shared API keys are stored. Third, a query planner handles cross-source queries by decomposing them into parallel sub-queries across different APIs, then merging and normalizing the results.

The post's most detailed section covers normalization challenges: the team built a universal date parser handling 14 different input formats, had to account for currency representations ranging from cents (Stripe) to dollars (QuickBooks) to micros (Google Ads), and navigated wildly inconsistent pagination and error-handling semantics — for example, a `429` from Stripe signals a 2-second backoff while the same code from HubSpot signals a daily limit breach. MCP was chosen over REST, GraphQL, and gRPC for its tool semantics, streaming-by-default responses, structured output guarantees, and transport flexibility. The post's closing advice to builders: invest in the normalization layer early, as data normalization decisions matter more than protocol choices.

Key facts

1. 01CorpusIQ is a single MCP endpoint connecting to 36 business APIs used by typical SaaS operators.
2. 02The system is read-only by design — no write operations, mutations, or webhooks.
3. 03Authentication uses OAuth 2.0 Device Authorization Grant; no passwords or API keys are stored.
4. 04A single unified query tool is exposed rather than 36 separate MCP tools, with a normalization layer handling routing and response formatting.
5. 05A query planner decomposes cross-source queries into parallel sub-queries and merges results.
6. 06Currency normalization was a major challenge: Stripe returns USD as cents, QuickBooks as dollars, and Google Ads as micros (millionths of a dollar).
7. 07The team built a universal date parser handling 14 different input formats across the 36 APIs.

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