Back to blog
Research

Our x402 Integration Is Live: Pay-Per-Call Access to Token Metrics—No API Key Required

Use your crypto wallet to call Token Metrics endpoints on demand. Pay per call with USDC or get a 10% discount with TMAI. No monthly subscriptions, no API keys, just headers and code.
Token Metrics Team
7 min read
Want Smarter Crypto Picks—Free?
See unbiased Token Metrics Ratings for BTC, ETH, and top alts.
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.
 No credit card | 1-click unsubscribe

Developers are already shipping with x402 at scale: 450,000+ weekly transactions, 700+ projects. This momentum is why our Token Metrics x402 integration matters for agents and apps that need real crypto intelligence on demand. You can now pay per API call using HTTP 402 and the x-coinbase-402 header, no API key required.

   _ 

Summary: Pay per API call to Token Metrics with x402 on Base using USDC or TMAI, set x-coinbase-402: true, and get instant access to trading signals, grades, and AI reports.

Check out the x402 ecosystem on Coingecko.

  

What You Get

Token Metrics now supports x402, the HTTP-native payment protocol from Coinbase. Users can call any public endpoint by paying per request with a wallet, eliminating API key management and upfront subscriptions. This makes Token Metrics data instantly accessible to AI agents, researchers, and developers who want on-demand crypto intelligence.

x402 enables truly flexible access where you pay only for what you use, with transparent per-call pricing in USDC or TMAI. The integration is live now across all Token Metrics public endpoints, from trading signals to AI reports. Here's everything you need to start calling Token Metrics with x402 today.

Quick Start

Get started with x402 + Token Metrics in three steps.

  1. Create a wallet client: Follow the x402 Quickstart for Buyers to set up a wallet client (Node.js with viem or Python with eth-account). Link: https://docs.cdp.coinbase.com/x402/docs/quickstart-buyers
  2. Set required headers: Add x-coinbase-402: true to any Token Metrics request. Optionally set x-payment-token: tmai for a 10% discount (defaults to usdc). Do not send x-api-key when using x402.
  3. Call any endpoint: Make a request to https://api.tokenmetrics.com/v2/[endpoint] with your wallet client. Payment happens automatically via x402 settlement.

That is it. Your wallet pays per call, and you get instant access to Token Metrics data with no subscription overhead.

Required Headers

  

Endpoint Pricing

Transparent per-call pricing across all Token Metrics public endpoints. Pay in USDC or get 10% off with TMAI.

  

  

  

  

All prices are per single call. Paying with TMAI automatically applies a 10% discount.

Try It on x402 Composer

If you want to see x402 + Token Metrics in action without writing code, head to x402 Composer. Composer is x402scan's playground for AI agents that pay per tool call. You can open a Token Metrics agent, chat with it, and watch real tool calls and USDC/TMAI settlements stream into the live Feed.

Composer surfaces active agents using Token Metrics endpoints like trading signals, price predictions, and AI reports. It is a great way to explore what is possible before you build your own integration. Link: https://x402scan.com/composer

Why x402 Changes the Game

Traditional API access requires upfront subscriptions, fixed rate limits, and key management overhead. x402 flips that model by letting you pay per call with a crypto wallet, with no API keys or monthly commitments. This is especially powerful for AI agents, which need flexible, on-demand access to external data without human intervention.

For Token Metrics, x402 unlocks agentic commerce where agents can autonomously pull crypto intelligence, pay only for what they use, and compose our endpoints with other x402-enabled tools like Heurist Mesh, Tavily, and Firecrawl. It is HTTP-native payments meeting real-world agent workflows.

What is x402?

x402 is an open-source HTTP-native payment protocol developed by Coinbase. It uses the HTTP 402 status code (Payment Required) to enable pay-per-request access to APIs and services. When you make a request with the x-coinbase-402 header, the server returns a payment challenge, your wallet signs and submits payment, and the server fulfills the request once settlement is verified.

The protocol runs on Base and Solana, with USDC and TMAI as the primary payment tokens. x402 is designed for composability, agents can chain multiple paid calls across different providers in a single workflow, paying each service directly without intermediaries. Learn more at the x402 Quickstart for Buyers: https://docs.cdp.coinbase.com/x402/docs/quickstart-buyers

FAQs

Do I need an API key to use x402 with Token Metrics?

No. When you set x-coinbase-402: true, your wallet signature replaces API key authentication. Do not send x-api-key in your requests.

Can I use x402 with a free trial or test wallet?

Yes, but you will need testnet USDC or TMAI on Base Sepolia (testnet) for development. Production calls require mainnet tokens.

How do I see my payment history?

Check x402scan for transaction logs and tool call history. Your wallet will also show outgoing USDC/TMAI transactions. Visit https://www.x402scan.com.

What happens if my wallet balance is too low?

The x402 client will return a payment failure before making the API call. Top up your wallet and retry.

Can I use x402 in production apps?

Yes. x402 is live on Base mainnet. Set appropriate spend limits and handle payment errors gracefully in your code.

Next Steps

Disclosure

Educational and informational purposes only. x402 involves crypto payments on public blockchains. Understand the risks, manage your wallet security, and test thoroughly before production use. Token Metrics does not provide financial advice.

Powered by Token Metrics

Your AI-powered crypto research experience is made possible by Token Metrics. Discover data-driven insights and advanced analytics on your favorite coins and tokens.

Build Smarter Crypto Apps &
AI Agents in Minutes, Not Months
Real-time prices, trading signals, and on-chain insights all from one powerful API.
Grab a Free API Key
About Token Metrics
Token Metrics: AI-powered crypto research and ratings platform. We help investors make smarter decisions with unbiased Token Metrics Ratings, on-chain analytics, and editor-curated “Top 10” guides. Our platform distills thousands of data points into clear scores, trends, and alerts you can act on.
30 Employees
analysts, data scientists, and crypto engineers
Daily Briefings
concise market insights and “Top Picks”
Transparent & Compliant
Sponsored ≠ Ratings; research remains independent
Want Smarter Crypto Picks—Free?
See unbiased Token Metrics Ratings for BTC, ETH, and top alts.
Thank you! Your submission has been received!
Oops! Something went wrong while submitting the form.
 No credit card | 1-click unsubscribe
Token Metrics Team
Token Metrics Team

Recent Posts

Research

API Management Essentials for Teams

Token Metrics Team
5

APIs are the connective tissue of modern software. As organizations expose more endpoints to partners, internal teams and third-party developers, effective api management becomes a competitive and operational imperative. This article breaks down practical frameworks, governance guardrails, and monitoring strategies that help teams scale APIs securely and reliably without sacrificing developer velocity.

Overview: What API management solves

API management is the set of practices, tools and processes that enable teams to design, publish, secure, monitor and monetize application programming interfaces. At its core it addresses three recurring challenges: consistent access control, predictable performance, and discoverability for developers. Well-managed APIs reduce friction for consumers, decrease operational incidents, and support governance priorities such as compliance and data protection.

Think of api management as a lifecycle discipline: from design and documentation to runtime enforcement and iterative refinement. Organizations that treat APIs as products—measuring adoption, latency, error rates, and business outcomes—are better positioned to scale integrations without accumulating technical debt.

Governance & Security: Policies that scale

Security and governance are non-negotiable for production APIs. Implement a layered approach:

  • Access control: Use token-based authentication (OAuth 2.0, JWT) and centralize identity validation at the gateway to avoid duplicating logic across services.
  • Rate limiting & quotas: Protect backend services and control cost by enforcing per-key or per-tenant limits. Different tiers can align with SLAs for partners.
  • Input validation & schema contracts: Define explicit contracts using OpenAPI/JSON Schema and validate at the edge to reduce injection and integration errors.
  • Audit & compliance: Log authentication events, data access, and configuration changes. Retain logs in a way that maps to regulatory obligations.

Combining automated policy enforcement at an API gateway with a governance framework (ownerable APIs, review gates, and versioning rules) ensures changes are controlled without slowing legitimate feature delivery.

Developer experience & the API product model

Developer experience (DX) determines adoption. Treat APIs as products by providing clear documentation, SDKs and a self-service developer portal. Key practices include:

  • Interactive docs: Publish OpenAPI-driven docs that allow developers to try endpoints in a sandbox.
  • Onboarding flows: Provide quick start guides, sample payloads and error explanations to reduce time-to-first-call.
  • Versioning strategy: Use semantic versioning and deprecation notices to minimize breaking changes.
  • Feedback loops: Instrument usage and surface developer issues to product owners so APIs evolve with consumer needs.

Metrics to track DX include signups, first successful call time, and repeat usage per key. These are leading indicators of whether an API is fulfilling its product intent.

Monitoring, observability & reliability

Operational visibility is essential for api management. Implement monitoring at multiple layers—gateway, service, and database—to triangulate causes when issues occur. Core telemetry includes:

  • Traffic metrics: requests per second, latency percentiles (p50/p95/p99), and throughput.
  • Error rates: HTTP 4xx/5xx breakdowns, client-specific failure patterns, and circuit-breaker triggers.
  • Business KPIs: API calls tied to revenue, conversions, or key workflows to prioritize fixes that have impact.

Observability practices—distributed tracing, structured logs, and context propagation—help teams move from alert fatigue to actionable incident response. Build runbooks that map common alerts to remediation steps and owners.

Implementation roadmap & tooling choices

Adopt an incremental roadmap rather than a big-bang rollout. A pragmatic sequence looks like:

  1. Inventory existing endpoints and annotate owners.
  2. Standardize contracts with OpenAPI and publish baseline docs.
  3. Introduce an API gateway for auth, rate limiting, and basic WAF rules.
  4. Instrument telemetry, set SLAs, and define retention for logs and traces.
  5. Launch a developer portal and iterate based on usage signals.

Choose tools that match team maturity: managed API platforms accelerate setup for companies lacking infra resources, while open-source gateways provide control for those with specialized needs. Evaluate vendors on extensibility, observability integrations, and policy-as-code support to avoid lock-in.

Build Smarter Crypto Apps & AI Agents with Token Metrics

Token Metrics provides real-time prices, trading signals, and on-chain insights all from one powerful API. Grab a Free API Key

What is API management and why does it matter?

API management encompasses the processes and tools required to publish, secure, monitor, and monetize APIs. It matters because it enables predictable, governed access to services while maintaining developer productivity and operational reliability.

Which components make up an API management stack?

Common components include an API gateway (auth, routing, rate limiting), developer portal (docs, keys), analytics and monitoring systems (metrics, traces), and lifecycle tooling (design, versioning, CI/CD integrations).

How should teams approach API security?

Implement defense-in-depth: centralized authentication, token validation, input schema checks, rate limits, and continuous auditing. Shift security left by validating contracts and scanning specs before deployment.

What metrics are most useful for API health?

Track latency percentiles, error rates, traffic patterns, and consumer-specific usage. Pair operational metrics with business KPIs (e.g., API-driven signups) to prioritize work that affects outcomes.

How do teams manage breaking changes?

Use explicit versioning, deprecation windows, and dual-running strategies where consumers migrate incrementally. Communicate changes via the developer portal and automated notifications tied to API keys.

When should an organization introduce an API gateway?

Introduce a gateway early when multiple consumers, partners, or internal teams rely on APIs. A gateway centralizes cross-cutting concerns and reduces duplicated security and routing logic.

Disclaimer

This article is for educational and informational purposes only. It provides neutral, analytical information about api management practices and tools and does not constitute professional or investment advice.

Research

How Modern Web APIs Power Connected Apps

Token Metrics Team
5

APIs are the connective tissue of modern software: they expose functionality, move data, and enable integrations across services, devices, and platforms. A well-designed web API shapes developer experience, system resilience, and operational cost. This article breaks down core concepts, common architectures, security and observability patterns, and practical steps to build and maintain reliable web APIs without assuming a specific platform or vendor.

What is a Web API and why it matters

A web API (Application Programming Interface) is an HTTP-accessible interface that lets clients interact with server-side functionality. APIs can return JSON, XML, or other formats and typically define a contract of endpoints, parameters, authentication requirements, and expected responses. They matter because they enable modularity: front-ends, mobile apps, third-party integrations, and automation tools can all reuse the same backend logic.

When evaluating or designing an API, consider the consumer experience: predictable endpoints, clear error messages, consistent versioning, and comprehensive documentation reduce onboarding friction for integrators. Think of an API as a public product: its usability directly impacts adoption and maintenance burden.

Design patterns and architectures

There are several architectural approaches to web APIs. RESTful (resource-based) design emphasizes nouns and predictable HTTP verbs. GraphQL centralizes query flexibility into a single endpoint and lets clients request only the fields they need. gRPC is used for low-latency, binary RPC between services.

Key design practices:

  • Model your resources to reflect domain concepts; avoid ad-hoc endpoints that duplicate behavior.
  • Keep contracts stable and use semantic versioning or evolving schema techniques (e.g., deprecation headers, feature flags) to handle changes.
  • Document thoroughly using OpenAPI/Swagger, GraphQL schemas, or similar—machine-readable specs enable client generation and automated testing.

Choose the pattern that aligns with your performance, flexibility, and developer ergonomics goals, and make that decision explicit in onboarding docs.

Security, authentication, and rate limiting

Security must be built into an API from day one. Common controls include TLS for transport, OAuth 2.0 / OpenID Connect for delegated authorization, API keys for service-to-service access, and fine-grained scopes for least-privilege access. Input validation, output encoding, and strict CORS policies guard against common injection and cross-origin attacks.

Operational protections such as rate limiting, quotas, and circuit breakers help preserve availability if a client misbehaves or a downstream dependency degrades. Design your error responses to be informative to developers but avoid leaking internal implementation details. Centralized authentication and centralized secrets management (vaults, KMS) reduce duplication and surface area for compromise.

Performance, monitoring, and testing

Performance considerations span latency, throughput, and resource efficiency. Use caching (HTTP cache headers, CDN, or in-memory caches) to reduce load on origin services. Employ pagination, partial responses, and batch endpoints to avoid overfetching. Instrumentation is essential: traces, metrics, and logs help correlate symptoms, identify bottlenecks, and measure SLAs.

Testing should be layered: unit tests for business logic, contract tests against API schemas, integration tests for end-to-end behavior, and load tests that emulate real-world usage. Observability tools and APMs provide continuous insight; AI-driven analytics platforms such as Token Metrics can help surface unusual usage patterns and prioritize performance fixes based on impact.

Build Smarter Crypto Apps & AI Agents with Token Metrics

Token Metrics provides real-time prices, trading signals, and on-chain insights all from one powerful API. Grab a Free API Key

What is the difference between REST and GraphQL?

REST exposes multiple endpoints that represent resources and rely on HTTP verbs for operations. It is simple and maps well to HTTP semantics. GraphQL exposes a single endpoint where clients request precisely the fields they need, which reduces overfetching and can simplify mobile consumption. GraphQL adds complexity in query planning and caching; choose based on client needs and team expertise.

How should I approach API versioning?

Prefer backward-compatible changes over breaking changes. Use semantic versioning for major releases, and consider header-based versioning or URI version prefixes when breaking changes are unavoidable. Maintain deprecation schedules and communicate timelines in documentation and response headers so clients can migrate predictably.

Which authentication method is best for my API?

OAuth 2.0 and OpenID Connect are standard for delegated access and single-sign-on. For machine-to-machine communication, use short-lived tokens issued by a trusted authorization server. API keys can be simple to implement but should be scoped, rotated regularly, and never embedded in public clients without additional protections.

How do I test and monitor an API in production?

Implement synthetic monitoring for critical endpoints, collect real-user metrics (latency percentiles, error rates), and instrument distributed tracing to follow requests across services. Run scheduled contract tests against staging and production-like environments, and correlate incidents with deployment timelines and dependency health.

How do I design for backward compatibility?

Make additive, non-breaking changes where possible: add new fields rather than changing existing ones, and preserve default behaviors. Document deprecated fields and provide feature flags to gate new behavior. Maintain versioned client libraries to give consumers time to upgrade.

Disclaimer

This article is educational and technical in nature. It does not provide legal, financial, or investment advice. Implementations should be evaluated with respect to security policies, compliance requirements, and operational constraints specific to your organization.

Research

API Endpoint Essentials: Design, Security & Tips

Token Metrics Team
5

APIs power modern software by exposing discrete access points called endpoints. Whether you re integrating a third-party data feed, building a microservice architecture, or wiring a WebSocket stream, understanding what an api endpoint is and how to design, secure, and monitor one is essential for robust systems.

What is an API endpoint and how it works

An api endpoint is a network-accessible URL or address that accepts requests and returns responses according to a protocol (usually HTTP/HTTPS or WebSocket). Conceptually, an endpoint maps a client intent to a server capability: retrieve a resource, submit data, or subscribe to updates. In a RESTful API, endpoints often follow noun-based paths (e.g., /users/123) combined with HTTP verbs (GET, POST, PUT, DELETE) to indicate the operation.

Key technical elements of an endpoint include:

  • URI pattern (path and optional query parameters)
  • Supported methods (verbs) and expected payloads
  • Authentication and authorization requirements
  • Response format and status codes
  • Rate limiting and throttling rules

Endpoints can be public (open to third parties) or private (internal to a service mesh). For crypto-focused data integrations, api endpoints may also expose streaming interfaces (WebSockets) or webhook callbacks for asynchronous events. For example, Token Metrics is an example of an analytics provider that exposes APIs for research workflows.

Types of endpoints and common protocols

Different application needs favor different endpoint types and protocols:

  • REST endpoints (HTTP/HTTPS): Simple, stateless, and cache-friendly, ideal for resource CRUD operations and broad compatibility.
  • GraphQL endpoints: A single endpoint that accepts queries allowing clients to request exactly the fields they need; reduces overfetching but requires careful schema design and complexity control.
  • WebSocket endpoints: Bidirectional, low-latency channels for streaming updates (market data, notifications). Useful when real-time throughput matters.
  • Webhook endpoints: Server-to-server callbacks where your service exposes a publicly accessible endpoint to receive event notifications from another system.

Choosing a protocol depends on consistency requirements, latency tolerance, and client diversity. Hybrid architectures often combine REST for configuration and GraphQL/WebSocket for dynamic data.

Design best practices for robust API endpoints

Good endpoint design improves developer experience and system resilience. Follow these practical practices:

  1. Clear and consistent naming: Use predictable URI patterns and resource-oriented paths. Avoid action-based endpoints like /getUserData in favor of /users/{id}.
  2. Versioning: Expose versioned endpoints (e.g., /v1/users) to avoid breaking changes for consumers.
  3. Input validation: Validate payloads early and return explicit error codes and messages to guide client correction.
  4. Pagination and filtering: For list-heavy endpoints, require pagination tokens or limits to protect backend resources.
  5. Documentation and examples: Provide schema samples, curl examples, and expected response bodies to accelerate integration.

API schema tools (OpenAPI/Swagger, AsyncAPI) let you define endpoints, types, and contracts programmatically, enabling automated client generation, testing, and mock servers during development.

Security, rate limits, and monitoring

Endpoints are primary attack surfaces. Security and observability are critical:

  • Authentication & Authorization: Prefer token-based schemes (OAuth2, JWT) with granular scopes. Enforce least privilege for each endpoint.
  • Transport security: Enforce TLS, HSTS, and secure ciphers to protect data in transit.
  • Rate limiting & quotas: Apply per-key and per-IP limits to mitigate abuse and preserve quality of service.
  • Input sanitization: Prevent injection attacks by whitelisting allowed fields and escaping inputs.
  • Observability: Emit structured logs, traces, and metrics per endpoint. Monitor latency percentiles, error rates, and traffic patterns to detect regressions early.

Operational tooling such as API gateways, service meshes, and managed API platforms provide built-in policy enforcement for security and rate limiting, reducing custom code complexity.

Build Smarter Crypto Apps & AI Agents with Token Metrics

Token Metrics provides real-time prices, trading signals, and on-chain insights all from one powerful API. Grab a Free API Key

What is the difference between an api endpoint and an API?

An API is the overall contract and set of capabilities a service exposes; an api endpoint is a specific network address (URI) where one of those capabilities is accessible. Think of the API as the menu and endpoints as the individual dishes.

How should I secure a public api endpoint?

Use HTTPS only, require authenticated tokens with appropriate scopes, implement rate limits and IP reputation checks, and validate all input. Employ monitoring to detect anomalous traffic patterns and rotate credentials periodically.

When should I version my endpoints?

Introduce explicit versioning when you plan to make breaking changes to request/response formats or behavior. Semantic versioning in the path (e.g., /v1/) is common and avoids forcing clients to adapt unexpectedly.

What are effective rate-limiting strategies?

Combine per-key quotas, sliding-window or token-bucket algorithms, and burst allowances. Communicate limits via response headers and provide clear error codes and retry-after values so clients can back off gracefully.

Which metrics should I monitor for endpoints?

Track request rate (RPS), error rate (4xx/5xx), latency percentiles (p50, p95, p99), and active connections for streaming endpoints. Correlate with upstream/downstream service metrics to identify root causes.

When is GraphQL preferable to REST for endpoints?

Choose GraphQL when clients require flexible field selection and you want to reduce overfetching. Prefer REST for simple resource CRUD patterns and when caching intermediaries are important. Consider team familiarity and tooling ecosystem as well.

Disclaimer

The information in this article is technical and educational in nature. It is not financial, legal, or investment advice. Implementations should be validated in your environment and reviewed for security and compliance obligations specific to your organization.

Choose from Platinum, Gold, and Silver packages
Reach with 25–30% open rates and 0.5–1% CTR
Craft your own custom ad—from banners to tailored copy
Perfect for Crypto Exchanges, SaaS Tools, DeFi, and AI Products