Helicone API
Official vendor OpenAPI document · agent-readyDeveloper ToolsMonitoring ObservabilityapiKey267 EndpointsREST
For Agents
Query logged LLM requests, score and annotate them, group calls into sessions, manage prompts and experiments, and run evaluators. Authenticates with an API key sent as a Bearer token in the Authorization header.
Use for: Query the most recent logged LLM requests, Get a logged request by its identifier, Attach a score to a logged request, List agent sessions and their metrics
Not supported: Does not run model inference itself. Use the Helicone API to log, query, and analyze LLM usage and to manage prompts, experiments, and keys.
The Helicone API logs and analyzes large language model requests for LLM applications. It queries logged requests and their inputs, attaches scores, feedback, and custom properties, groups calls into agent sessions with metrics, manages prompts and prompt versions, runs prompt experiments and evaluators, and administers provider keys and API keys.
Install Jentic One Beta
Connect the Helicone API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Helicone API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
1
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fhelicone.ai%2Fhelicone" | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fhelicone.ai%2Fhelicone" | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with Helicone API.
Query logged LLM requests and their inputs
Attach scores, feedback, and custom properties to requests
Query agent sessions and their metrics
Manage prompts and prompt versions
Run and query prompt experiments and evaluators
Manage provider keys and API keys
Use Cases
Patterns agents use Helicone API for, with concrete tasks.
★ LLM Request Monitoring
An AI agent connected through Jentic can inspect how an LLM application is behaving. It queries logged requests, reads their inputs and scores, and pulls request metrics, so an assistant can surface error rates, latency, or cost trends without a separate dashboard session.
Query the most recent logged requests and summarize their error rate
Prompt Experimentation
Teams iterating on prompts need to compare versions against data. The Helicone API creates experiments, manages datasets, and runs evaluators over them, letting an agent set up a comparison and read back the scored results.
Create an experiment and run an evaluator over its dataset
Session Analytics
Multi-step agents produce sessions rather than single calls. The Helicone API queries sessions, their names, and aggregate metrics, so an agent can report on how a conversation or workflow performed end to end.
Query sessions and return their aggregate metrics
Key Endpoints
267 endpoints — the helicone api logs and analyzes large language model requests for llm applications.
METHOD
PATH
DESCRIPTION
POST
/v1/request/query
Query logged LLM requests
GET
/v1/request/{requestId}
Get a logged request by ID
POST
/v1/session/query
Query agent sessions
POST
/v1/experiment/query
Query prompt experiments
POST
/v1/prompt-2025/query
Query prompts
GET
/v1/models
List models
POST
/v1/request/query
Query logged LLM requests
GET
/v1/request/{requestId}
Get a logged request by ID
POST
/v1/session/query
Query agent sessions
POST
/v1/experiment/query
Query prompt experiments
POST
/v1/prompt-2025/query
Query prompts
GET
/v1/models
List models
Why Jentic?
What agents get from Jentic-routed access to this vendor.
Setup
Wiring Helicone by hand means creating an API key, building request and session queries, and paging through large result sets yourself. Through Jentic you install once, import Helicone from the API Directory, store the key once, and your agent calls the query and management operations directly.
Permission scoping
You choose which of the operations your agent may call and can keep it to read-only queries. You might allow request and session queries while blocking key management and prompt edits.
Credential isolation
Your Helicone API key is stored once, encrypted, by your own Jentic One instance and injected at execution time. It never enters the agent's prompt, logs, or context.
Intent-based discovery
Agents search Jentic by intent such as 'query logged LLM requests', and Jentic returns the matching Helicone operation with its input schema so the agent calls it with the right filters.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Helicone API through Jentic.
What authentication does the Helicone API use?
Most operations authenticate with an API key sent as a Bearer token in the Authorization header, per the OpenAPI spec. A few public endpoints, such as the model list, need no key. Through Jentic the key is stored once, encrypted, by your own self-hosted instance and injected when the agent calls, so it never appears in the agent's prompt or logs.
Can I limit what my agent is allowed to do with the Helicone API?
Yes. You choose which operations the agent may call and can keep it to read-only queries. You might allow request and session queries while blocking key management and prompt edits, with every call logged by your own instance.
Is there a Helicone MCP server?
You don't need an MCP server to give your agent the Helicone API. Jentic connects it directly from the API Directory: import it, store your key once, and your agent calls the request, session, and experiment operations. Operations are discovered on demand, so nothing extra loads into the agent's context.
What are the rate limits for the Helicone API?
The OpenAPI spec does not define rate limits. Check the Helicone documentation for current plan limits before running high-volume queries against the request logs.
What can I do with the Helicone API?
You can query logged LLM requests and their inputs, attach scores and feedback, group calls into sessions with metrics, manage prompts and their versions, run experiments and evaluators, and administer provider and API keys.
How do I query LLM request logs through Jentic?
Search Jentic by intent, for example 'query logged LLM requests', and Jentic returns the matching Helicone operation with its input schema. Your agent supplies the filters and reads back the matching requests. To run it on your own infrastructure, install Jentic One from its GitHub repo.
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