# API FAQ
SUMMARY: Common API questions — auth, rate limits, error handling, endpoint discovery.

API FAQ
Common questions about the Synapse API.
How do I authenticate?
Two methods:
1. Mind Key (for data endpoints): 
2. JWT (for account endpoints): 
Or via query parameter (60 req/min limit): 
See Authentication.
What's the difference between Mind Key and JWT?
- Mind Key: tenant-scoped, never expires, for memory/chat/tasks data
- JWT: user-scoped, 7-day expiry, for account/mind management
See Mind Key vs JWT.
Why am I getting 401 Unauthorized?
Common causes:
1. Missing  header
2. Invalid Mind Key (verify it starts with )
3. Using a JWT where a Mind Key is required (or vice versa)
4. Mind Key has been revoked
Fix: Verify your token. See Authentication.
Why am I getting 404 Not Found?
You used a wrong endpoint path. Synapse only has the paths listed in
.
Fix: Call  to see all valid paths. Don't guess.
Why am I getting 429 Too Many Requests?
You're using  query parameter auth, which is rate-limited to 60/min.
Fix: Switch to  header (no rate limit).
See Rate Limits.
How do I list all endpoints?
[CODE BLOCK]
How do I find the right endpoint?
1. Check  for the machine-readable list
2. Check  for full API docs
3. Browse  for the documentation system
4. Use  for OpenAPI 3.0 spec
Can I use GET instead of POST?
Some POST endpoints have GET equivalents for URL-only tools:
-  ↔ 
-  ↔ 
-  ↔ 
Check  for available GET variants.
How do I handle errors?
All errors return JSON:
[CODE BLOCK]
See Errors & Error Handling.
What's the request body limit?
10 MB. For larger payloads (e.g. file uploads), use the multipart endpoints.
Does the API support CORS?
Yes. All endpoints return:
[CODE BLOCK]
Is there an SDK?
Yes:
- Node.js: 
- MCP: 
See API Overview for details.
How do I paginate?
Use  and :
[CODE BLOCK]
Default limit: 100. Max: 500.
Can I filter memories by category or tag?
Yes:
[CODE BLOCK]
How do I search memories?
Two ways:
1. FTS5 keyword search: 
2. Semantic search: 
See FTS5 Search and Semantic Search.
How do I update a memory?
POST  with the same  +  — the existing memory is
updated, not duplicated.
[CODE BLOCK]
How do I delete a memory?
[CODE BLOCK]
Can I bulk delete?
Yes:
[CODE BLOCK]
Next Steps
- API Overview
- Errors & Error Handling
- Authentication