Official vendor OpenAPI document · agent-readyAnalyticsBusiness IntelligenceapiKey, bearer4 EndpointsREST
For Agents
Search eBay sold listings and pull price statistics and recent comparable sales for an item or graded trading card. The data operations are read-only GETs taking an API key or bearer token.
Use for: Search for recent eBay sold prices for a product, Get price statistics and comparable sales for a graded trading card, Find all sold listings for a search from the last year, Check what a collectible actually sold for including accepted Best Offers
Not supported: Does not handle listing items for sale, payment processing, or inventory management. Use for looking up eBay sold prices and trading-card comps only.
The CompsAPI API returns real eBay sold prices as structured JSON, with up to three years of sales history and real accepted Best Offer prices. It serves sold listings newest-first for a search and a comps endpoint that computes price statistics alongside the ten most recent matching sales. A dedicated trading-card layer covers graded cards, so an agent can price a specific collectible from what it actually sold for rather than from asking prices.
Install Jentic One Beta
Connect the CompsAPI to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the CompsAPI, 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%2Fcompsapi.com%2Fcompsapi" | 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%2Fcompsapi.com%2Fcompsapi" | 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 CompsAPI API.
Search eBay sold listings for a query and read them newest sale first
Compute price statistics plus the ten newest matching sales for a card or item
Price graded trading cards from real accepted sale prices, including Best Offer figures
Read up to three years of sold-price history for a search
Check the current UTC-day usage without spending against the request allowance
Use Cases
Patterns agents use CompsAPI API for, with concrete tasks.
★ Trading-Card Price Comps
A reseller agent prices a graded trading card by reading real accepted sale prices rather than optimistic listing prices. CompsAPI returns price statistics and the ten newest matching sales from eBay, including accepted Best Offer figures, so the agent can set an ask that reflects what the card actually trades for.
Call GET /v1/comps for a specific graded card to read its price statistics and the ten most recent comparable sales
Resale Price Research
Before listing an item, an agent searches CompsAPI for completed eBay sales matching the product and reads them newest sale first across up to three years of history. This grounds a resale decision in real transaction data, including accepted Best Offers that ordinary search results hide.
Call GET /v1/sold for a product search and read the completed sales newest first to estimate resale value
AI Agent Integration via Jentic
An AI agent reaches CompsAPI through Jentic without handling the API key itself. It searches by intent, receives the matching operation and its input schema, and executes the call with the credential injected at run time. This lets the agent fetch sold-price comps as a grounding step before it drafts a listing or answers a valuation question.
Search Jentic for 'eBay sold prices', load the GET /v1/sold schema, and execute it with Jentic-managed credentials
Key Endpoints
4 endpoints — the compsapi api returns real ebay sold prices as structured json, with up to three years of sales history and real accepted best offer prices.
METHOD
PATH
DESCRIPTION
GET
/v1/sold
Sold listings for a search, newest sale first
GET
/v1/comps
Price stats plus the ten newest matching sales
GET
/v1/usage
Usage for the current UTC day
GET
/v1/health
Service status
GET
/v1/sold
Sold listings for a search, newest sale first
GET
/v1/comps
Price stats plus the ten newest matching sales
GET
/v1/usage
Usage for the current UTC day
GET
/v1/health
Service status
Jentic AI Readiness Score
This API is usable in Jentic One now. Its AI-readiness score against Jentic's framework shows where it stands today and where improvements would make it even easier for agents to use.
C
CompsAPI
- Foundational (D)46/100
93
Foundational Compliance61
Developer Experience & Jentic Compatibility22
AI-Readiness & Agent Experience94
Agent Usability55
Security63
AI DiscoverabilityPowered by JenticScoring Framework 1.0.0 | Scoring Engine 0.4.2
Show dimension breakdown
93
Foundational Compliance
Base layer of spec validity and structural soundness.
Grade: A+Signals: 4
98%
Lint Results
Aggregated quality score from linter diagnostics, weighted by severity.
100%
Resolution Completeness
Percentage of `$ref` references that resolve successfully.
100%
Specification Validity
Checks whether the API description parses successfully and conforms to its declared specification (e.g., OpenAPI).
75%
Structural Integrity
Structural correctness score based on schema issues using logarithmic dampening.
61
Developer Experience & Jentic Compatibility
Clarity, completeness, and ingestion readiness for developers and tooling.
Grade: B-Signals: 4
1%
Example Density
How richly the API is illustrated with examples.
100%
Example Validity
Percentage of examples that conform to their schemas.
44%
Response Coverage
Percentage of operations with complete response definitions (success, client error, server error).
100%
Tooling Readiness
Health of API ingestion, bundling, and resolution within Jentic pipelines.
22
AI-Readiness & Agent Experience
Semantic breadth, depth, and agent comprehension for AI systems.
Grade: FSignals: 4
36%
Description Coverage
Coverage of descriptions across API elements.
0%
Error Standardization
Coverage of RFC 9457 Problem Details for error responses.
0%
OperationId Quality
Coverage, uniqueness, and casing consistency of operationIds for AI inference.
50%
Summary Coverage
Coverage of summaries across operations/tags/info.
94
Agent Usability
Functional utility, complexity comfort, and AI orchestration readiness.
Grade: A+Signals: 1
94%
Complexity Comfort
Agent comfort level based on API operational and structural complexity.
55
Security
Trust, risk posture, and security compliance.
Grade: CSignals: 1
55%
Authentication Strength
Average quality of security schemes based on authentication method strength (weakest link for OAuth2).
63
AI Discoverability
Findability, semantic richness, and reasoning readiness.
Grade: B-Signals: 1
62%
Descriptive Richness
Clarity and depth of descriptions across API elements.
Score it yourself
Every API in the directory is allowlisted, so you can re-score it with no key required.
npx @jentic/api-scorecard-cli score <openapi-url>Why Jentic?
What agents get from Jentic-routed access to this vendor.
Setup
Wiring CompsAPI by hand means managing its API key, choosing between the X-API-Key header and a bearer token, and handling your daily usage window yourself. Through Jentic you install once, import CompsAPI from the API Directory, store the key once, and your agent calls it.
Permission scoping
This API is read-only: it serves only GET lookups against sold-price data, so a rule can confine your agent to reading prices and nothing that changes state. You choose which of the reads it may call, so the sold-listings and comps lookups can be allowed while the usage check is withheld.
Credential isolation
Your CompsAPI 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 'eBay sold prices' or 'trading card comps', and Jentic returns the matching CompsAPI operation with its input schema so the agent calls the right endpoint without browsing the reference docs.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using CompsAPI API through Jentic.
What authentication does the CompsAPI use?
The CompsAPI authenticates with an API key sent in the X-API-Key header, or alternatively a bearer token in the Authorization header, per its OpenAPI spec. The health endpoint is open and needs no credential. Through Jentic the key is stored encrypted by your own Jentic One instance and injected at execution time, so it never reaches the agent.
Can I price a graded trading card with the CompsAPI?
Yes. The comps operation returns price statistics plus the ten newest matching sales for a card, including real accepted Best Offer prices, so an agent can value a graded card from what it actually sold for. The sold-listings operation adds the fuller completed-sales history behind that figure.
What are the rate limits for the CompsAPI?
The OpenAPI spec does not publish specific rate-limit numbers; check https://compsapi.com/docs for the current limits on your plan. The usage operation reports your consumption for the current UTC day and does not itself count against the allowance, so an agent can check where it stands before a batch of lookups.
Is there a CompsAPI MCP server?
You don't need an MCP server to give your agent CompsAPI. Jentic connects it directly from the API Directory: import it, store your credential once, and your agent calls the sold-price and comps operations. Nothing extra is loaded into the agent's context until an operation is actually invoked.
Can I limit what my agent is allowed to do with the CompsAPI?
Yes. CompsAPI is read-only, so write a rule that allows only the lookups it needs, for example the sold-listings and comps reads, and the agent can research prices and nothing else. Because every call runs through your own Jentic One instance, each one is logged for you to review.
How do I look up sold prices with the CompsAPI through Jentic?
Search Jentic for 'eBay sold prices', and it returns the CompsAPI sold-listings operation with its input schema. Load the schema and execute GET /v1/sold with your search terms and the credential injected at run time. To run it on your own infrastructure, install Jentic One from its GitHub repo.
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