Claude API vs OpenAI API from PHP: practical differences
Tested both APIs for a document analysis task. Sharing observations on the PHP side: client libraries, rate limits, and response characteristics.
No official Anthropic PHP SDK (as of writing). Used a Guzzle wrapper around the REST API directly.
There are community PHP wrappers for Claude (claude-php and a few others on Packagist). Thin wrappers around Guzzle with message formatting. Nothing as polished as openai-php/client but functional.
The message format is slightly different: Claude uses a messages array like OpenAI but the system prompt goes in a separate system field, not as a role: system message. Easy to miss.
Claude 3 Haiku is very fast and cheap for classification and extraction tasks. Performance is close to GPT-3.5 but with better instruction following. For our document parsing pipeline we switched to Haiku and costs dropped 70%.
Rate limits on Claude are tighter per-minute but higher per-day. If you have bursty traffic, OpenAI handles it better. If you have sustained steady throughput, Claude limits are fine.
Streaming with Claude works the same as OpenAI (SSE format). The event types are slightly different: content_block_delta instead of a delta field directly. Easy to adapt existing streaming code.