0x is the institutional-grade DEX aggregation and crypto liquidity infrastructure platform that powers token swaps inside hundreds of consumer wallets, exchanges, and onchain apps (Coinbase, MetaMask, Phantom, Brave, Rainbow, Matcha, and more). The 0x API surface aggregates 150+ liquidity sources — public AMMs and exclusive professional market makers — across 20+ EVM chains, with cross-chain reach into Solana, HyperCore, and Tron via 16+ bridge providers. Settlement runs through the Permit2-based 0x Settler contracts, and integrators get a unified API key, a TypeScript SDK, an official Agent Skill, and a hosted MCP server for AI-assisted development.
- Website: https://0x.org
- Documentation: https://docs.0x.org
- Dashboard / Sign Up: https://dashboard.0x.org/create-account
- Pricing: https://0x.org/pricing
- GitHub: https://github.com/0xProject
- Status: https://status.0x.org
Institutional-grade DEX aggregation returning indicative prices, firm quotes, and ready-to-sign transaction calldata for token swaps across 150+ liquidity sources on 20+ EVM chains. Two allowance flows: AllowanceHolder (recommended, multisig-friendly) and Permit2 (gas-optimised with EIP-712).
- Base URL:
https://api.0x.org - Authentication: API key header
0x-api-key+ version header0x-version: v2 - OpenAPI: openapi/0x-api.yaml
- Documentation: https://docs.0x.org/0x-swap-api/introduction
Lets end users swap tokens without holding the native gas asset (ETH, BNB, AVAX, etc.). The taker signs Permit2 + meta-transaction EIP-712 payloads off-chain; 0x relayers submit on-chain. Gas fees are deducted from the sell token.
- Base URL:
https://api.0x.org - Authentication: API key header
0x-api-key+ version header0x-version: v2 - OpenAPI: openapi/0x-api.yaml
- Documentation: https://docs.0x.org/gasless-api/introduction
Any-token, any-chain bridging API aggregating 16+ bridge providers (Across V4, Relay, Bungee, CCIP, Squid Coral, NEAR Intents, OFT, Mayan, Circle CCTP, Arbitrum / Linea / Superchain canonical bridges, HyperCore). Includes streaming quote updates and reaches Solana, HyperCore, and Tron.
- Base URL:
https://api.0x.org - Authentication: API key header
0x-api-key - OpenAPI: openapi/0x-cross-chain.yaml
- Documentation: https://docs.0x.org/cross-chain-api/introduction
Read-only API for retrieving the integrator's historical swap and gasless trade records with surplus, integrator fee accrual, taker, route, and per-trade settlement detail. Used for monetisation reporting and accounting reconciliation.
- Base URL:
https://api.0x.org - OpenAPI: openapi/0x-api.yaml
Returns the active aggregated liquidity sources (AMMs, RFQ market makers, private liquidity venues) currently routed against by the Swap and Gasless engines on a given chain.
- Base URL:
https://api.0x.org - OpenAPI: openapi/0x-api.yaml
| Spec | Description |
|---|---|
| openapi/0x-api.yaml | 0x API v2 — Swap, Gasless, Sources, Trade Analytics (14 operations) |
| openapi/0x-cross-chain.yaml | 0x Cross-Chain API v1 — quotes, status, sources, history, streaming (5 operations) |
| Schema | Description |
|---|---|
| json-schema/0x-swap-quote-schema.json | Firm swap quote with calldata |
| json-schema/0x-swap-price-schema.json | Indicative swap price |
| json-schema/0x-gasless-trade-schema.json | Gasless trade payload + approval |
| json-schema/0x-gasless-trade-status-schema.json | Gasless trade lifecycle status |
| json-schema/0x-cross-chain-quote-schema.json | Cross-chain bridge quote |
| json-schema/0x-supported-chain-schema.json | Supported chain descriptor |
| json-schema/0x-liquidity-source-schema.json | Liquidity source descriptor |
| json-schema/0x-trade-analytics-record-schema.json | Single trade record (analytics) |
| json-schema/0x-error-schema.json | Canonical 0x error envelope |
| Structure | Description |
|---|---|
| json-structure/0x-swap-quote-structure.json | Field-level docs for the firm swap quote |
| json-structure/0x-gasless-trade-structure.json | Field-level docs for the gasless trade lifecycle |
| Context | Description |
|---|---|
| json-ld/0x-context.jsonld | Linked-data context for 0x entities (SwapQuote, GaslessTrade, CrossChainQuote, etc.) |
| Ruleset | Description |
|---|---|
| rules/0x-rules.yml | Lint rules enforcing the 0x API conventions (header auth, kebab-case paths, camelCase params, namespaced operationIds) |
| Capability | Description |
|---|---|
| capabilities/0x-api-swap.yaml | Swap surface (5 operations, REST + MCP exposers) |
| capabilities/0x-api-gasless.yaml | Gasless surface (6 operations, REST + MCP exposers) |
| capabilities/0x-api-trade-analytics.yaml | Trade Analytics surface (2 operations) |
| capabilities/0x-api-sources.yaml | Sources surface (1 operation) |
| capabilities/0x-cross-chain-cross-chain.yaml | Cross-Chain surface (5 operations) |
| Example | Description |
|---|---|
| examples/0x-swap-allowance-holder-get-price-example.json | Indicative price for WETH→USDC on Ethereum |
| examples/0x-swap-allowance-holder-get-quote-example.json | Firm quote with calldata (WETH→USDC on Base) |
| examples/0x-swap-permit2-get-quote-example.json | Permit2 quote with EIP-712 typed data |
| examples/0x-swap-get-chains-example.json | Supported chains for the Swap API |
| examples/0x-gasless-get-quote-example.json | Gasless USDC→WETH quote |
| examples/0x-gasless-submit-trade-example.json | Submit a signed gasless trade |
| examples/0x-gasless-get-status-example.json | Poll a gasless trade status |
| examples/0x-cross-chain-get-quotes-example.json | Bridge USDC Ethereum → Base via Across vs Relay |
| examples/0x-trade-analytics-swap-example.json | Two days of integrator swap trades |
| examples/0x-sources-get-sources-example.json | Enabled liquidity sources on Ethereum |
| Vocabulary | Description |
|---|---|
| vocabulary/0x-vocabulary.yml | 0x domain vocabulary (Swap, Gasless, Permit2, Settler, RFQ, Trade Surplus, etc.) |
| Artifact | Description |
|---|---|
| plans/0x-plans-pricing.yml | API Commons Plans — Free / Standard ($1k/mo + 0.15%) / Custom ($2.5k+/mo) tiers |
| rate-limits/0x-rate-limits.yml | API Commons Rate Limits — per-tier RPS envelopes (1/5/100 RPS) plus per-quote freshness window |
| finops/0x-finops.yml | FinOps Framework / FOCUS 1.3 mapping for subscription, swap fee, trade surplus, and integrator monetisation |
| Tool | URL |
|---|---|
| MCP Server | https://docs.0x.org/_mcp/server |
Claude Code Skill (0x-api) |
https://github.com/0xProject/0x-ai |
| Install command | npx skills add 0xProject/0x-ai |
| Library | URL |
|---|---|
| 0x Parser (TypeScript) | https://github.com/0xProject/0x-parser — published as @0x/0x-parser on npm |
| TypeScript OpenAPI SDK template | https://github.com/0xProject/0x-swap-ts-sdk-migration |
| Code Examples Collection | https://github.com/0xProject/0x-examples |
| 0x Settler Contracts | https://github.com/0xProject/0x-settler |
Swap & Gasless (canonical EVM chain IDs): Ethereum (1), Abstract (2741), Arbitrum (42161), Avalanche (43114), Base (8453), Berachain (80094), BNB (56), HyperEVM (999), Ink (57073), Linea (59144, Swap only), Mantle (5000), Monad (143), Optimism (10), Plasma (9745), Polygon (137), Scroll (534352), Sonic (146), Tempo (4217), Unichain (130), World Chain (480).
Cross-Chain destinations also include: Solana, HyperCore, Tron (with virtual chain IDs documented at supported-chains).
- x-type: company
- x-tier: 1 (commercial DEX aggregator with full product surface)
- Tags: Cryptocurrency, DeFi, DEX Aggregator, Swap, Gasless, Cross-Chain, Permit2, Liquidity, Trade Analytics, Web3, Settlement, Smart Contracts
FN: Kin Lane Email: kin@apievangelist.com