kitio.aiOpenAI API vs Zep
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. OpenAI API starts at See pricing page and Zep starts at $125/mo. Check both pricing pages for current plans.
At a glance
Best for
Category
Pricing model
Starting price
Free plan
Made by
Based in
Rating
Key features
- Responses API
- Agents SDK
- Realtime voice API
- Image and audio models
- Batch API
- Fine-tuning and evals
- Temporal knowledge graph
- Entity extraction
- Context assembly
- Graphiti open source
- Python, TS and Go SDKs
| Feature | OpenAI API | Zep |
|---|---|---|
| Best for | Developer API for GPT, reasoning, image, audio and embedding models | Context engineering platform with temporal knowledge graph memory |
| Category | Models & APIs | Models & APIs |
| Pricing model | Paid | Freemium |
| Starting price | See pricing page | $125/mo |
| Free plan | No | Yes |
| Made by | OpenAI | Zep AI |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
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Pricing compared
OpenAI API starts at See pricing page and Zep starts at $125/mo. Check both pricing pages for current plans.
Free plan
Cheapest paid plan
Top plan
Free trial
3 plans
GPT-6 Luna
$0.10 / $0.50 per 1M tokens
- Input / output
- Fast, low-cost model
- 1.05M context
GPT-6.1 Sol
$2 / $10 per 1M tokens
- Input / output
- Balanced model
- 1.05M context
GPT-6 Astra
$10 / $50 per 1M tokens
- Input / output
- Most capable model
- 1.05M context
3 plans
Flex
$125/mo
- 50,000 credits/mo, then $25/10K
- 600 requests per minute
- 5 projects
- Unlimited memories and users
Flex Plus
$375/mo
- 200,000 credits/mo, then $75/40K
- 1,000 requests per minute
- 10 projects
- HIPAA BAA
Enterprise
Custom
- Custom credits, negotiated rates
- Zep Cloud or your VPC
- Guaranteed rate limits with SLA
Prices in USD, checked Oct 28, 2026 or later. Plans change often, so confirm on each tool's site before you buy.
Pros and cons
OpenAI API
- Wide model range in one API
- Mature SDKs and docs
- Built-in tools like web search
- Top models are costly at scale
- Rate limits depend on spend tier
- Model names change frequently
Zep
- Tracks how facts change
- Open-source graph engine
- Good for business data
- Hosted platform is cloud only
- Graph concepts take learning
- Credit pricing needs tracking
Which one should you choose?
Choose OpenAI API if you want:
- Wide model range in one API
- Mature SDKs and docs
- Built-in tools like web search
Watch out: top models are costly at scale.
Choose Zep if you want:
- Tracks how facts change
- Open-source graph engine
- Good for business data
Watch out: hosted platform is cloud only.
OpenAI API vs Zep FAQ
What is the difference between OpenAI API and Zep?
OpenAI API: Developer API for GPT, reasoning, image, audio and embedding models. Zep: Context engineering platform with temporal knowledge graph memory. Both are models & apis tools.
Is OpenAI API or Zep cheaper?
OpenAI API starts at See pricing page and Zep starts at $125/mo. Check both pricing pages for current plans.
Do OpenAI API and Zep have free plans?
OpenAI API: No. Zep: Yes.
Who makes OpenAI API?
OpenAI API is made by OpenAI, based in United States.
Who makes Zep?
Zep is made by Zep AI, based in United States.
Which should I choose, OpenAI API or Zep?
Choose OpenAI API if you value wide model range in one api and mature sdks and docs. Choose Zep if you value tracks how facts change and open-source graph engine.