"Respan helps us debug and deploy LLM models with confidence 10x faster than we ever could before."
- Roshan Kumaraswamy, CTO, Apten
The YC Sprint - From Idea to First Customer
Apten launched with a simple mission: help companies automate lead conversion through AI-powered SMS. Their agents quickly proved effective in capturing and nurturing leads, and the company gained momentum straight out of Y Combinator.
By the end of their first sprint, Apten was already handling thousands of messages every day.
The Blind-Spot Moment
Scaling brought a new problem. Apten's team realized it was nearly impossible to understand why an AI agent responded incorrectly during complex, multi-step conversations. Debugging often meant:
- Manually texting the agent
- Copying logs into Jupyter notebooks
- Running one-off experiments
Testing new prompts or reproducing customer issues could take hours, slowing down development exactly when speed mattered most.
Plugging In - Minutes to First Log
That changed once Apten integrated Respan. With a single config swap - pointing traffic through the Respan proxy - they began capturing every detail of their LLM interactions.
- Wrapping their SMS handler with a decorator
- Enabling async logging
took only minutes, and suddenly Apten had a real-time view of every message, token, latency spike, and tool-call flowing through their agents.
On top of that, Apten could immediately spin up experiments inside Respan: running side-by-side prompt variations, comparing model outputs, and testing fixes against real customer logs. What used to take hours of manual replaying now happened instantly, right inside the same dashboard where the logs lived.
Measurable Impact
The shift was dramatic:
- 5x faster debugging
- Under 100 ms error response time
- 99% monitoring accuracy
Apten now logs 150,000+ LLM requests every day through Respan, adding up to millions each month. Developers who once struggled to reproduce edge cases can now trace every step with full visibility, turning hours of manual debugging into minutes.
Scaling Beyond SMS
Since onboarding to Respan, Apten has expanded its offering to include AI Voice and AI Email. The platform now engages leads across multiple channels, following up, answering questions, and nurturing conversations like a human sales rep would.
With Respan as the observability backbone, Apten continues to scale with confidence, matching the needs of enterprise customers while moving at startup speed.
