How rate limits, exhausted quotas, outages and webhook failures from the APIs you call show up, and how to catch them.
Claude API rate limits: RPM, input and output tokens per minute, cache-aware ITPM, anthropic-ratelimit headers, spend-cap 429s and what to log.
How an Anthropic API outage shows up: 529 overloaded_error, 500, 504, mid-stream errors, plus spend limit and credit balance errors, and detection.
What a Cloudflare outage looks like from your side: branded vs unbranded 502/504, 52x codes, the status feed and how to detect an edge failure in logs.
Gemini API rate limits: RPM, TPM and RPD per project, tiers, spend-based limits, 429 RESOURCE_EXHAUSTED versus 402, and what to log to catch throttling.
GitHub API rate limits for REST and GraphQL: primary and secondary limits, x-ratelimit headers, the 200 that hides a GraphQL limit, and what to log.
The OpenAI 429 codes for empty credits and spend caps, why retries never fix them, how they differ from rate limit 429s and how to catch them in logs.
How an OpenAI API outage appears: 500, 503 server_is_overloaded, Retry-After, what is not an outage, the status page and how to detect it per model.
OpenAI rate limits by the numbers: RPM, TPM, tiers, x-ratelimit headers, slow_down 429s and the fields to log so you see throttling before users do.
Salesforce API limits: the 24-hour request allocation, concurrency cap, REQUEST_LIMIT_EXCEEDED 403s, Sforce-Limit-Info and /limits, and what to log.
How Shopify throttles apps: REST Admin 40-request bucket and X-Shopify-Shop-Api-Call-Limit, GraphQL cost points by plan, 429s, and what to log.
When Stripe returns a 5xx the outcome is unknown. How idempotency keys, webhooks and the status page keep payments correct, and how to detect an outage.
How a Supabase outage shows up in your logs: 5xx and 54x codes, PGRST000-003, Edge Function errors, the new status page and how to detect it fast.
How a Twilio outage shows up: 20500 and 5xx API errors, undelivered messages, why SMS retries can duplicate, the status page and how to detect it.
Which Vercel errors mean the platform failed and which are your code: INTERNAL_ codes, 502/503/504, status components, custom error pages and detection.