Free and community-run API endpoints fail in patterns, not at random. Gateway timeouts, upstreams that vanish, model catalogs that shrink overnight, keys that stop working between one session and the next. None of that is your configuration's fault — but telling provider death from your own misconfiguration takes about sixty seconds if you know the three checks.
Your agent will retry, wrap the error, and show you something unhelpful like 'request failed'. Cut through all of it with one direct request to the endpoint. If curl fails the same way the agent does, the problem is upstream and no amount of config editing will fix it.
Free endpoints are usually thin fronts over someone else's paid capacity: trial credits, promo quotas, or resold accounts. When the credits run out or the upstream rotates, the front keeps standing — it just starts returning 503s, or quietly drops models from /v1/models, or lets streams start and then die mid-generation when a quota trips partway through.
This is why free-endpoint failures feel personal but aren't: the same Tuesday, hundreds of people hit the identical wall. The practical response is not to find a magically stable free endpoint (they exist until they don't) but to make switching endpoints cheap enough that a dead one costs you minutes, not an evening.
| What you see | What it usually means | Next move |
|---|---|---|
| 504 gateway timeout, every request | Upstream dead or overloaded | Confirm with curl, then switch endpoints — this one is done for now |
| SSE stream starts then dies mid-answer | Quota or credit cutoff partway through generation | Retry once; if it repeats, the free tier is throttling you |
| 401 after working fine yesterday | Key revoked or quota exhausted | Check the provider console for quota/billing state before touching config |
| 404 on a model that worked last week | Provider removed it from the catalog | Re-list /v1/models and pick from what actually exists |
| Everything works from your phone's hotspot but not your network | Local blocklist, VPN, or DNS | Not the provider — check your network path |
AgentRouter is an Anthropic-compatible router with per-token pricing and setup docs for 15 tools — Claude Code, Codex, Cline, Aider, OpenCode and more. Keeping it configured as your fallback turns a dead free endpoint into a one-line switch instead of a rebuild. Same surface, same variable names, documented model list.
Set up your fallback endpoint →Referral link — we may earn a reward if you sign up, at no extra cost to you. This is the same advice we would give with no link at all. Check their current pricing and model list on their own site; we deliberately do not restate numbers that change.
The Setup Doctor walks through your tool, symptom, and setup and points at the likely cause — no account needed.