OpenAI-compatible API integration and troubleshooting
Focus on solving Base URL, API Key, Model ID, Chat Completions, SSE, tool calls, /v1/v1, 401, 404, 429 and 502 issues of OpenAI Compatible API.
Remember these four things first
Confirm the agreement and evidence first, and then start changing configurations or replacing services.
- 01
Confirm whether the client automatically appends /v1 to avoid /v1/v1 appearing in the final address.
- 02
The model ID is copied from the console or /models return without using display name guessing.
- 03
Test normal responses, SSE, tool calls and usage respectively, and save status codes and request IDs.
- 04
401, 404, 429 and 5xx are handled for different reasons and do not use infinite retries to cover up configuration errors.
Find the guide for your issue
Use curl, Python and Node.js to complete the first call and troubleshoot 401, model not found and /v1/v1.
View steps 02 · Error troubleshootingOpenAI Compatible Base URL Online CheckerCheck HTTPS, duplicate /v1 segments, complete endpoints, and final request paths to identify /v1/v1 and 404 errors quickly.
View steps 03 · Error troubleshootingModel not found and /v1/v1 troubleshootingIdentify model ID, 404, and duplicate-version path errors using /v1/models, account permissions, and the full request URL.
View steps 04 · Error troubleshooting401, 429, 502 API error troubleshootingUse HTTP status codes to identify API key, quota, rate-limit, gateway, and upstream model problems.
View steps 05 · Error troubleshooting401 invalid_api_key and API Key invalid troubleshootingTroubleshoot 401 errors by checking request headers, environment variables, the Base URL, the key provider, and configuration overrides. Avoid ineffective retries and key exposure.
View steps 06 · Error troubleshooting429 Too Many Requests and API rate limiting troubleshootingDistinguish between frequency, token, concurrency, quota and retry amplification, and use Retry-After, exponential backoff and queue recovery calls.
View steps 07 · Error troubleshooting502 Bad Gateway, stream disconnected and SSE disconnection troubleshootingLocate 502s, upstream errors, and streaming interruptions with short requests, non-streaming comparisons, SSE events, and layered timeouts.
View steps 08 · Quick StartLLM API streaming and SSE integration guideValidate streaming responses with curl, Python and Node.js and troubleshoot proxy buffering, interruptions and missing usage.
View steps 09 · Platform ReferenceLLM API Compatibility MatrixCompare Chat Completions, Responses, Anthropic Messages, streaming, tool calls, and multimodal capabilities.
View steps 10 · Quick StartLLM API Pre-production ChecklistVerify keys, protocols, timeout and retry behavior, logging, cost monitoring, staged rollout, and rollback readiness.
View stepsFAQ
These answers are also written into structured data on the page for easy search and reference.
Where should the OpenAI Compatible Base URL be filled in?
Most compatible clients fill in the version path, such as https://www.aifast.club/v1. If the client automatically appends /v1, it should be adjusted based on the final request log to avoid repeated paths.
Why does /models succeed but chat still fails?
/models only proves that base authentication and model list links are available. Also check the real model ID, Chat Completions path, request fields, streaming format, and account permissions.
Chat Completions is successful, can it be used directly in Codex?
It cannot be inferred directly. Codex custom Provider requires Responses API and corresponding event semantics; Chat Completions success cannot replace Responses, tool invocation and session recovery acceptance.
Reference and Check Sources
- OpenAI Chat API Reference
Review Chat Completions request, response, and streaming structures.
- RFC 9110: HTTP Semantics
Review HTTP methods, status codes, and retry semantics.
- OWASP API Security Top 10
Check authentication, resource consumption, and API security risks.
Use the console's live catalog as the source of truth for model IDs, prices, and availability.