The Impulse Labs API enforces a sliding window rate limit per user per 60-second period.
Limits by plan
| Plan | Requests / 60 seconds |
|---|
| Pro | 120 |
| Team | 300 |
| Enterprise | 1 000 |
Limits apply to validated inference requests — each call to POST /infer counts as one request against your limit.
POST /infer includes these headers:
| Header | Type | Description |
|---|
X-RateLimit-Limit | integer | Maximum requests allowed in the window |
X-RateLimit-Remaining | integer | Requests remaining in the current window |
X-RateLimit-Reset | integer | Unix timestamp (seconds) when the window resets |
Retry-After | integer | Seconds to wait (only present on 429 responses) |
curl -si -X POST "https://inference.impulselabs.ai/infer" \
-H "Authorization: Bearer $IMPULSE_API_KEY" \
-H "Content-Type: application/json" \
-d '{"deployment_id": "my-model", "inputs": {}}' \
| grep -i x-ratelimit
# X-RateLimit-Limit: 120
# X-RateLimit-Remaining: 118
# X-RateLimit-Reset: 1708346460
Handling 429 Too Many Requests
When you exceed the limit, the API returns:
HTTP/1.1 429 Too Many Requests
Retry-After: 34
X-RateLimit-Limit: 120
X-RateLimit-Remaining: 0
X-RateLimit-Reset: 1708346460
{
"valid": false,
"error": "Rate limit exceeded",
"limit": 120,
"retry_after_seconds": 34
}
Recommended retry strategy
- Read the
Retry-After header and wait that many seconds before retrying.
- Do not retry immediately in a tight loop — this will keep triggering the limit.
- For batch workloads, spread requests over time or use exponential backoff.
Python — respect Retry-After
import time, requests
def safe_infer(session, payload, headers):
while True:
resp = session.post(
"https://inference.impulselabs.ai/infer",
json=payload,
headers=headers,
)
if resp.status_code == 429:
wait = int(resp.headers.get("Retry-After", 5))
print(f"Rate limited. Retrying in {wait}s...")
time.sleep(wait)
continue
resp.raise_for_status()
return resp.json()
Upgrading your plan
If you consistently hit rate limits, consider upgrading to a higher plan at app.impulselabs.ai/billing.
For custom limits or Enterprise pricing, contact us. 
