Frequently asked questions
Honest answers about how HeurChain works, what you own, and what it costs. If your question is not here, email [email protected].
What's the difference between Hosted and Enterprise?
Hosted ($5/mo) is a single-tenant plan for one person. You get one memory store with one login, and every AI tool you use — ChatGPT, Claude, Cursor, custom scripts — writes into that same store. There are no per-agent fees.
Enterprise ($49/mo + $9.99/seat) is built for a team or department. Each Enterprise subscription is its own isolated tenant. If Engineering and Marketing need separate memory workspaces, they each get their own Enterprise subscription. See Pricing for full caps.
What counts as an "agent"? Do I get charged per agent?
An agent is any software that makes API calls into your tenant — a ChatGPT conversation, a Claude session, a Cursor plugin, a LangChain script, a cron job, a sub-agent, anything. Agents are not billed separately on any plan. All plans include unlimited agents. See the formal definition in our Terms.
Can I upgrade or downgrade later?
Yes. Upgrades and downgrades are handled through the Stripe Customer Portal — the link is in your welcome email and on the dashboard. Changes take effect at the next billing cycle. You will not lose any stored data when changing plans.
What happens if I exceed my plan's vector or operation cap?
Requests that exceed a rate limit receive an HTTP 429 response immediately. If you approach your storage or monthly operation cap, you will receive a notification before your account is blocked. You will have 30 days notice before any overage charges take effect. See the Pricing page for full fair-use policy details.
Do you have a free tier?
There is no free hosted tier. However, HeurChain is MIT-licensed open source — you can run the full stack yourself on your own infrastructure at no cost to us. The GitHub repo has Docker Compose instructions that get you running in under 10 minutes. View on GitHub.
Who owns the data I store in HeurChain?
You do. Your data lives in your tenant, isolated from all other tenants. HeurChain does not mine your stored vectors for training data, does not share them with model providers, and does not index them for any other customer's queries. See our Privacy Policy for the full details.
Can I download my full memory at any time?
Yes. From the dashboard, use "Download vault" to get a zip of your complete memory. No waiting period, no request form. If you have recent writes that have not been consolidated yet, use "Flush working memory to vault" first — the process takes under a minute.
What happens to my data if I cancel?
Your tenant and all stored data are retained for 30 days after your subscription ends, so you can still export everything. After that 30-day window, your tenant, vectors, and account records are permanently and irreversibly deleted. Export your data before cancelling if you need to keep it. This policy is written into our Terms of Service, not just the marketing.
Is my data used to train any AI model?
No. Your stored vectors are never used to train HeurChain's own systems or any third-party AI model. Your tenant is isolated at the storage layer — other tenants cannot read your data, and HeurChain does not pass it to any model provider. See Privacy Policy section 3 for the formal statement.
Where is my data physically stored?
HeurChain runs on Hetzner infrastructure in Falkenstein, Germany, with Cloudflare in front. Data is stored in the EU. A US region is planned. Enterprise Custom customers can discuss data residency requirements directly with sales.
What's a tenant?
A tenant is an isolated data silo — its own vector memory store, API key, and vault directory. Nothing written to your tenant is ever visible to any other tenant. On the Hosted plan you have one. On Enterprise, each subscription creates one. The formal definition is in Terms of Service section 5.
What's a seat?
A seat is a human user account — one login attached to a tenant. Each seat represents one person who can access the tenant's dashboard, manage settings, and rotate the API key. Hosted includes one seat. Enterprise includes one seat and allows additional seats at $9.99/month each.
What's an agent?
An agent is any software making API calls into a tenant — a ChatGPT conversation, a Claude session, a Cursor coding agent, a LangChain pipeline, a custom cron job. Agents are not billed separately on any plan. All plans include unlimited agents.
If I'm a solo user on Hosted, how many agents can write into my memory?
Unlimited. The whole point of the Hosted plan is that all your AI tools — ChatGPT, Claude, Gemini, Cursor, your own scripts — write into the same single tenant. You pay $5/month for the tenant; you do not pay per agent. This is the key thing the old pricing copy failed to communicate clearly.
Can two teammates share a tenant?
Yes, on Enterprise. The Enterprise plan is designed for this: the base subscription includes one seat, and you add teammates at $9.99/seat/month. All seats write into the same shared tenant. If two teams need separate siloed memory, each team buys its own Enterprise subscription — each gets its own isolated tenant.
Does HeurChain work with ChatGPT? Claude? Gemini?
Yes to all three. HeurChain exposes a plain HTTP API — any tool that can make a web request can read and write memory. Direct integrations exist for Claude (via MCP) and Cursor (via plugin). ChatGPT, Gemini, and any other platform connect through a standard HTTP call. If your agent can POST to a URL, it works.
Do I need to be a developer to use it?
The hosted plan is designed to be usable by anyone who can configure a plugin or paste an API key. For ChatGPT and Claude, you configure the MCP connector with your tenant's API key. For more custom setups — LangChain pipelines, custom scripts — some coding is required. The self-hosted version is developer-only.
Is there a library/SDK or just the HTTP API?
Both. The core interface is a plain HTTP REST API (two main routes: /store and /query). A Python client library and TypeScript client are available in the GitHub repo. MCP server mode is also supported for Claude and Cursor.
Can I self-host instead of paying?
Yes. HeurChain is MIT-licensed open source. The GitHub repo includes Docker Compose configuration that brings up the full stack — broker, Qdrant, Redis, embedding service — in under 10 minutes. Self-hosting means you run your own infrastructure; HeurChain provides no support for self-hosted deployments beyond the documentation.
Does it work with Obsidian?
Not with a native plugin today, but Obsidian notes can be imported into your tenant via the HTTP API or via a script that reads your vault directory. Because HeurChain returns memory in readable text, you can also export your tenant and import it back into Obsidian. A dedicated Obsidian plugin is on the roadmap.
Is my data encrypted?
Yes. Data is encrypted in transit with TLS. Data at rest is encrypted with AES-256 at the storage layer. Enterprise Custom plans can discuss per-tenant key management. See our Privacy Policy for the full security statement.
Who can read my data besides me?
Nobody under normal circumstances. Your tenant is isolated at the storage layer. HeurChain staff can access raw infrastructure for maintenance and incident response, but tenant data is never accessed for business purposes. We do not share your data with model providers, advertisers, or third parties. See Privacy Policy section 3.
Do you have a SOC 2 or ISO 27001 certification?
Not yet. We are a small, early-stage company. SOC 2 Type II is on our security roadmap, but we do not have a timeline to share publicly. We will not claim certifications we do not hold. If you require SOC 2 or ISO 27001 as a procurement requirement, Enterprise Custom is the right conversation — email [email protected].
How do I report a security issue?
Email [email protected] with a description of the issue. Please do not disclose vulnerabilities publicly before we have had a chance to investigate and respond. We aim to acknowledge all security reports within 48 hours.
Are you open source?
Yes. The core HeurChain broker, MCP server, and client libraries are MIT-licensed and available on GitHub. The hosted service runs this same codebase on managed infrastructure. You can inspect the code, run it yourself, or contribute.