FINDING 01·Developers and integration builders working with complex SaaS APIs·2 sources
Inconsistent and Poorly Versioned API Design
Developers building integrations against APIs with fragmented versioning (e.g. mixing V1, V3, V4 endpoints for related operations) face significant friction, especially when core features like sorting, filtering, or key object associations lack consistent API support.
Source
“If I need to fetch associations between objects I have to use their V4 associations API but if I want to fetch contact lists I need to use their V1 API, and to fetch contacts themselves I sometimes have to use a V1 API and sometimes a V3 API. Who is versioning all of this”
Source
“Hubspot released Sequences 10 years ago, and somehow they still don't have API support. Meanwhile... It's 2024 and somehow none of their APIs support sorting, ordering or filtering and to do so you need to use their /search endpoint.”
FINDING 02·Developers integrating payment and enterprise APIs·2 sources
Poor Support and Unclear Documentation from API Providers
Developers report that when integrations break, API provider support is unhelpful — often suggesting technology switches rather than diagnosing root causes — and documentation is insufficient to prevent or resolve common errors.
Source
“I'm incurring into very frustrating problems with the system and with the support assistance, too. Every time we have a problem the support assistance invites us to change the implementation technology, from SOAP, to SDK, to NVP, etc.. After 3 days of working (from coding with SOAP (PHP) up to the attempt to start the SDK's examples) no solution has yet been found.”
Source
“Has anyone else built integrations for hubspot and just been completely fed up with their terrible developer experience compared to other sales tools? Outreach, Salesloft, Apollo, and Salesforce have just blown them out of water in that aspect.”
FINDING 03·Developers using AI coding assistants for API integration·1 source
AI Agents Using Outdated API Docs and Deprecated SDKs
As of early 2026, AI coding agents (e.g. Cursor) frequently reach for stale documentation or deprecated SDK versions when helping developers integrate APIs, producing broken integrations. This is a recent and growing pain as AI-assisted development becomes mainstream.
Source
“The agents kept reaching for outdated docs and deprecated SDK versions, often falling back to training data instead of reading the current API documentation. We tested this ourselves with Cursor. Across multiple iterations, 87% of runs fetched outdated reference docs using web search, and 13% of implementations used a deprecated SDK version.”
FINDING 04·Frontend and full-stack developers·1 source
CORS and Network Errors in Frontend-to-Backend API Calls
Developers frequently encounter CORS misconfigurations and network errors when wiring frontend apps to backend API endpoints, even when the same endpoint works correctly via Postman or curl — pointing to environment-specific integration gaps.
Source
“When I use postman to try the http://localhost:5001/api/stripe/create-checkout-session POST I get 200k and a session ID in return as well as using curl. When I try the actual redirect on my billing page when clicking activate subscription nothing happens and console produces a network error.”
FINDING 05·Cloud/backend developers using AWS infrastructure·3 sources
Cloud Service Integration Misconfiguration (API Gateway, Lambda, DynamoDB)
Developers integrating AWS services (API Gateway, Lambda, DynamoDB, Lex) frequently hit silent failures — requests stuck, triggers not added, cross-account routing unsupported — with opaque error messages and complex infrastructure dependencies.
Source
“If I manually add an Integration Request of type Lambda function, an Api Gateway trigger is automatically added to the lambda function. If I do it via Terraform, everything looks correct but when I go look at the Lambda function it has no trigger.”
Source
“If they're in separate accounts, I can't figure out how to signal to API Gateway that the dynamo table is in a different account.”
Source
“When I type a message on the website and click Ask, the chatbot just shows "Thinking…" and never responds.”
FINDING 06·Developers integrating third-party APIs·1 source
Authentication & Authorization Failures
Developers across many APIs and time periods consistently struggle with auth errors — OAuth token failures, PKCE requirements, HMAC signing issues, and 'Unauthorized' responses — often with little actionable guidance from docs or support.
Source
“COULDN'T COMPLETE THE CONNECTION Authorization failed because the code challenge parameter is missing. PKCE is required for this authorization request. Please contact the app developer.”
FINDING 07·IoT/smart home application developers·1 source
Hardware/IoT API Connectivity Gaps
Developers trying to connect physical IoT devices (sensors, hubs) via HTTP APIs face undocumented limitations — devices work in vendor mobile apps but cannot be reached programmatically, leaving integration paths unclear.
Source
“We bought Aqara temperature sensors and Aqara hub, and they can be connected to the mobile Aqara application. However, we cannot connect to them through HTTP API. Also, for connection to the Alexa thermostat we also have the problems because we cannot enable the thermostat.”