capturly 0.4.0

Record, replay, and debug any HTTP API — with built-in AI traffic intelligence

Capturly

Record, replay, and debug any HTTP API — with built-in AI traffic intelligence

Capturly is an HTTP proxy that captures, replays, and inspects API traffic. It works with any REST/GraphQL endpoint but goes deeper on AI protocols — automatically detecting OpenAI and AGUI (Agent GUI) traffic, extracting system prompts, combining streaming chunks, and surfacing tool calls.

Quick Start

# Install
pip install capturly

# Point at OpenAI and watch traffic
capturly --mode log --backend https://api.openai.com --combine-chunks

# Open dashboard at http://localhost:9090
# See your system prompts, tool definitions, and complete conversations

Use Cases

Debug AI Applications

See exactly what your app sends to OpenAI:

capturly --mode log --backend https://api.openai.com --combine-chunks
# Configure your app to use http://localhost:9999 instead of api.openai.com

The dashboard extracts:

• System prompts (including multi-part array content)
• Tool definitions and tool calls
• Token usage
• Complete conversation history (streaming chunks combined)
• AGUI agent runs: messages, tool calls, reasoning, and state

Create Deterministic Test Fixtures

Record real API responses, replay them in tests:

# Record once
capturly --mode record --backend https://api.stripe.com
curl http://localhost:9999/v1/charges

# Replay forever (no network, instant, deterministic)
capturly --mode replay
pytest tests/

Performance Testing

Stress test your service with cached responses:

# Replay with zero delay (simulate fast API)
capturly --mode replay --delay 0

# Or simulate slow upstream
capturly --mode replay --delay 2000

Development Speedup

Cache common endpoints, record new ones automatically:

capturly --mode hybrid --backend https://api.example.com
# First request: hits backend, caches response
# Subsequent requests: instant replay from cache

Dashboard

The built-in web dashboard (default: http://localhost:9090) provides:

• Traffic list with filtering (All / AI / Non-AI), pagination, and protocol badges (AI, AGUI, SSE)
• AI detail view — system prompts, tool definitions, message history, assistant response, token usage
• AGUI detail view — run metadata, reconstructed messages, tool calls with parsed arguments, reasoning, state snapshots
• Generic detail view — collapsible request/response bodies and headers
• Truncate — clear the traffic log with one click

Modes

Mode	Behavior	Use When
record	Proxy to backend, save responses	Capturing test fixtures
replay	Return saved responses (no backend)	Running tests, offline dev
hybrid	Replay if cached, record if new	Day-to-day development
log	Proxy and persist full traffic	Debugging, AI inspection

Configuration

CLI arguments:

capturly --mode log --backend https://api.openai.com --port 8080

Environment variables:

export CAPTURLY_RECORDINGS_DIR=./recordings
capturly --mode record --backend https://api.example.com

Installation

pip install capturly

Requirements: Python 3.9+

Documentation

• Getting Started — 5-minute tutorial
• Mode Reference — Detailed behavior of each mode
• Configuration — All options, all sources

Contributing

Contributions welcome! See CONTRIBUTING.md for guidelines.

License

MIT License - see LICENSE file.