Typescript API Documentation Guide for Crypto Apps

Your swap is ready to go, but the docs are a mess. One file says the wallet query returns a balance object, another example passes limit, and the SDK's error output changes depending on which endpoint you hit. That's the point where a TypeScript API documentation problem turns into a production problem, because the engineer can't tell whether the bug is in the code, the contract, or the example.

In crypto, bad docs don't just slow down onboarding. They break swaps, hide pagination bugs, and make market data clients look safe when they aren't. Good typescript api documentation gives a developer enough structure to build, verify, and recover when the chain, the feed, or the wallet response doesn't behave the way the happy path promised.

Introduction to TypeScript API Documentation for Crypto Projects

A crypto team can ship an SDK and still lose developers at the docs page. The break usually shows up fast. A Solana swap sample assumes the wrong token decimals, a wallet read example omits the error shape, or a price feed snippet works only on the happy path. At that point, TypeScript API documentation is part of the product, because it tells engineers whether the interface is stable enough to use.

TypeScript matters here because it ties docs to source code, declarations, and release history. Its public timeline moved from 0.8 in October 2012 to 1.0 on 12 April 2014, then through releases such as union types in 1.4, ES6 modules and decorators in 1.5, JSX support in 1.6, and async/await in 1.7 during 2015. The official release history is now a standard reference for how the language grew (TypeScript release history). For API docs, that maturity matters. Library authors have to explain types, declarations, and compatibility while the JavaScript and Node ecosystems keep shifting.

Crypto APIs make that requirement concrete. Solana's official TypeScript guidance points developers to @solana/kit for RPC, transactions, codecs, and signers, while Orca's example shows a real swap flow in TypeScript, including inputAmount: 1_000_000n for 1 USDC with 6 decimals and slippageToleranceBps: 100 for a 1% slippage cap (Solana docs, Orca developer overview). Those examples only hold up when the docs explain runtime validation, failure cases, and the exact shape of the response.

Practical rule: if a developer cannot answer “what does this call need, what can fail, and what do I do next?” from the docs, the integration is not ready.

Core Categories of TypeScript API Documentation Systems

Crypto teams usually need more than one documentation system, and the failure mode is trying to force one tool to cover source comments, API contracts, and developer workflow at once. TSDoc captures intent in the codebase, TypeDoc turns those symbols and comments into reference docs, OpenAPI or Swagger describe REST services, and SDK docs help developers find the right method from autocomplete or a browser. Each layer serves a different audience.

Choosing Your Documentation Category by Use Case

Project Type	Primary Tool	Output Format	Crypto Example	Best For
TypeScript library or SDK	TSDoc plus TypeDoc	HTML or JSON	Swap SDK methods, wallet helpers, signing utilities	Public classes, functions, types, and method reference
REST service for wallets, swaps, or market data	TypeScript types plus OpenAPI or Swagger	JSON spec and hosted docs	Price feed endpoints, quote responses, transaction payloads	HTTP endpoints, request bodies, responses, and versioning
Developer SDK used in editors	TSDoc plus README patterns	Inline help, examples, and reference links	Wallet connect flows, autocomplete hints, typed request builders	Discoverability, import ergonomics, and working snippets
Multi-module app with no single entry point	TypeDoc with expanded entry-point strategy	HTML or JSON	Separate modules for swaps, wallets, and analytics	Distributed module surfaces and file-by-file reference

The categories are different for a reason. A swap SDK needs method-level clarity, a wallet service needs request and response contracts, and a price feed needs a stable shape that frontend code can parse without guesswork.

TSDoc is the lowest-level discipline. It keeps the comment immediately above the declaration in a /** ... */ block and uses tags like @param and @returns to describe inputs and outputs without repeating what the type system already says (TSDoc and TypeDoc overview). TypeDoc reads those comments, follows symbols, and renders them into published reference docs (TypeDoc docs).

For REST-heavy crypto services, OpenAPI is the right layer when the goal is endpoint contracts instead of library signatures. For SDKs, the docs also have to get a developer from install to authenticated request without guessing. That means the IDE experience matters, because developers often read autocomplete first and the website second.

A practical setup usually combines the layers instead of replacing one with another. TSDoc gives maintainers a place to explain runtime validation, error shapes, and the behavior behind a swap quote or wallet lookup. TypeDoc publishes that material in a form teams can ship alongside the SDK. OpenAPI covers the network boundary where versioning, request bodies, and response schemas need to stay explicit.

Short version: document the source, generate the reference, then write the service docs around the workflows people actually run in wallets, swaps, and price feeds.

Writing Effective Doc Comments with TSDoc in Crypto Code

A TSDoc comment belongs directly above the declaration, inside a /** ... */ block, where TypeScript and tooling can read it. Keep it short and specific. Describe intent, inputs, outputs, and any runtime constraint that the type alone does not capture. If the signature already says page?: number, do not repeat that it is a number unless the docs need to explain a real limit or default.

Wallet query example

A wallet query like getAssetsByOwner should tell the user what the address means, how pagination behaves, and what the sort options change. The Helius TypeScript SDK shows those fields clearly, with ownerAddress, page, limit: 50, and sort settings exposed as explicit API inputs (Helius TypeScript SDK).

A useful comment can stay this simple:

• Purpose: fetch the assets held by a wallet.
• Inputs: owner address, page, limit, and sort settings.
• Return value: a paginated asset set the client can display or filter.

That is enough for a reference page, and it stays honest. A comment should not restate what the signature already makes obvious or turn into a mini tutorial on pagination.

Swap example

A swap method needs the same discipline, but the docs also have to warn about execution risk. Orca's example uses inputAmount: 1_000_000n for 1 USDC and slippageToleranceBps: 100 for a 1% cap, so the comment should say that the trade can still fail if execution moves outside that tolerance. That belongs next to the method, not buried in a README note.

A good swap comment also helps IDE discoverability. Developers scan autocomplete first, and they need the return shape, failure mode, and any preflight checks in the same place they see the method name. That matters more than long prose. Keep one short example that mirrors real wallet and swap flows, then stop before the comment starts aging faster than the code.

Generating Reference Docs with TypeDoc for Libraries and Apps

TypeDoc works well when the source code is the contract. It reads exported symbols and doc comments from source, follows re-exports, and can resolve entry points from package.json exports or main fields. That makes it a practical fit for SDKs where the public surface is much smaller than the full repository.

For a crypto library, the setup should stay tight. Point TypeDoc at the public entry file, then verify that the generated output only includes what consumers should import. If the package has a clean top-level client export, the docs stay readable. If the package spreads APIs across several files, TypeDoc's --entryPointStrategy Expand can document each file separately, which helps when the surface is not centered on one module.

A practical Solana example

Suppose a Solana swap package exposes @solana/kit for chain access and @orca-so/whirlpools for swap math. The docs should show the public entry points, the generated symbol list, and the exact place where a swap call starts. That matters when a developer moves between wallet queries, swap builders, and transaction signing in one flow.

Output choice matters too. HTML works for humans, but JSON is useful when another tool needs to index or search the docs. TypeDoc supports both, so teams can publish a browsable site and still feed the same reference data into internal tooling or SDK portals.

A sane generation loop looks like this:

1. Point TypeDoc at the public entry point.
2. Check that re-exports are followed correctly.
3. Generate HTML for the website and JSON for tooling.
4. Verify that private internals do not leak into the reference.

That last check matters more than people expect. In crypto SDKs, accidental exposure of internal helpers creates confusion fast, because a developer will copy the wrong function into a trading bot and then blame the chain when the import was the actual problem.

Documenting Runtime Validation and Error Shapes Beyond Types

Static types can make a client feel safer than it really is. In crypto, that gap shows up fast. A typed response can still be malformed at runtime, a market feed can drift, and a swap or wallet API can return a failure shape the signature never promised. Recent TypeScript API guidance for clients keeps pushing the same lesson, validate responses, narrow errors explicitly, and show the fallback path in the docs instead of stopping at the happy path (runtime validation guidance).

Happy path versus real path

A minimal example says, “call the endpoint and read the typed fields.” A production-grade example says, “parse the body, verify the shape, handle non-2xx responses, and decide what happens when the feed is stale or the payload is incomplete.” That difference matters in trading, where one bad assumption can make the UI show a price that no longer exists.

The docs should make the failure mode visible. If a Solana swap quote comes back with a slippage violation, the reader needs to know whether the client throws, retries, or surfaces a typed error object like { code: 'SLIPPAGE_EXCEEDED', retryable: false }. If a wallet query can return a partial account payload, show the null-handling path in the example. If the API supports version drift, say so directly.

A short validation snippet helps more than a polished promise. For example:

const result = SwapQuoteSchema.safeParse(responseBody)

if (!result.success) {
  throw {
    code: 'INVALID_QUOTE_PAYLOAD',
    retryable: false
  }
}

The mistake is overtrusting the type checker. A typed method signature can cover the nominal contract, but it cannot guarantee that the live response is valid or that the upstream service stayed consistent. That is why validation belongs in the docs, not just in the code.

Practical rule: if the docs only show one green-path call, they teach trust without recovery.

For crypto teams, the reference page should include a short error-shape table or a typed failure example. Not every endpoint needs a long explanation. It just needs enough detail that a wallet app or market dashboard can fail loudly instead of showing stale data.

Versioning OpenAPI Generation and Hosting Your Documentation

A crypto API breaks trust fast when the docs drift from the release. TypeScript changes have followed a predictable release cadence for years, so docs should follow the same discipline without pretending one hosted page can describe every package state.

For REST services, generate OpenAPI or Swagger from the TypeScript source and publish it with the code. That setup works well for swap endpoints, market data endpoints, and wallet APIs that are consumed over HTTP. The spec then drives the reference docs, client generation, and the hosted version people read.

A clean publish workflow usually looks like this:

• Build the API spec from the TypeScript types.
• Tag the docs with the package or service version.
• Publish the handbook and reference together.
• Keep release notes aligned with breaking changes.

That alignment matters because TypeScript library consumers need more than syntax. They need to know when a declaration changed, when a field moved, and when a method is deprecated. If the release notes and handbook drift apart, downstream teams waste time reading source they should never have had to inspect.

For a public crypto service, versioned docs also make support easier. If a developer reports a bug, you can point them to the exact reference that matches their package or endpoint release. Host old versions too, so a team integrating an older SDK does not have to guess whether the current page applies. Publish the generated OpenAPI spec alongside the Solana Tracker Data API version.

Keep the docs pipeline as strict as the code pipeline. If the generated reference no longer matches the source, the build should fail. That kind of check catches drift early, before a wallet app or swap client ships against stale documentation.

Cross References and Navigation for Discoverable Crypto SDKs

A crypto SDK only feels simple when the docs guide developers to the first working call fast. In an editor, they want the import, the signature, the runtime validation, and the error shape before they dig through the full symbol list. SDK guidance still points in the same direction, JSDoc on every public method, a short README that covers installation, authentication, error handling, and a link to the full reference, plus top-level exports and small constructor inputs so IDEs can surface the right path quickly (SDK design guidance).

What good navigation looks like

Good SDK docs connect related types instead of leaving them in separate pages. If a swap method returns a transaction object, link to the transaction type. If a wallet query accepts pagination, point the page and limit fields back to the shared list-query pattern. That cross-reference helps a developer move from one concept to the next without hunting through unrelated files.

The README should stay narrow. Installation, authentication, one working request, one error example, and a link to the full reference are enough for most SDKs. Everything else belongs in the generated docs or the example directory.

Authentication docs need a concrete path. Chainlink's TypeScript example for Data Streams does that well, create an auth-example.ts file, set STREAMS_API_KEY and STREAMS_API_SECRET as environment variables, and run the sample with ts-node (Chainlink TypeScript authentication example). That is easier to follow than burying credential setup in prose, because the developer can copy the pattern and move on.

Wallet and asset queries should follow the same pattern. For example, a Solana SDK can lead with import { SolanaTracker } from "@solanatracker/sdk" and call getAssetsByOwner() as the first working example, instead of opening with a long index of symbols. For asset lookup flows, the docs should show how page, limit, and sorting appear in the method signature, so the reference matches how the client is used. The Helius TypeScript SDK follows that shape for its own client docs, which is a useful pattern to mirror for teams building around public APIs.

Quick Reference for Typescript API Documentation

Public method checklist

• Comment placed correctly: use a /** ... */ block immediately above the declaration.
• Purpose stated: explain what the method does in one sentence.
• Parameters covered: use @param for each meaningful input.
• Return value covered: use @returns when the output needs clarification.
• Failure path shown: include the runtime error or validation behavior when it matters.
• Example included: keep it short and crypto-specific.

TSDoc tag cheat sheet

• @param for request fields, wallet inputs, or swap settings.
• @returns for balances, transactions, or parsed responses.
• @example for a one-screen usage snippet.
• @remarks for constraints like decimals, slippage, or pagination behavior.

Copy-paste crypto snippets

For a swap example, keep the values explicit and small enough to understand:

• Swap input: inputAmount: 1_000_000n
• Meaning: 1 USDC with 6 decimals
• Risk guard: slippageToleranceBps: 100
• Meaning: 1% slippage cap

For a wallet query, make the pagination obvious:

• Owner field: ownerAddress
• Pagination field: page
• Page size: limit: 50
• Sort behavior: spell out the sorting options in the comment

TypeDoc commands to verify

Run the generator against the public entry point, then inspect the result for missing or leaked symbols. If the docs are for a distributed crypto app, use the expanded entry-point strategy so each module is documented on its own. If the package has a clean client entry, keep the surface narrow and confirm the generated output matches what a consumer should import.

Fast check: if a developer can't find the first working swap, wallet, or auth example in under a minute, the docs are too hard to use.

Solana Tracker publishes a real-time trading terminal, a unified data API, low-latency WebSocket streams, RPC infrastructure, and a DEX aggregation engine with risk analysis tools like Rugcheck and wallet tracking. If you're building around Solana swaps, wallet queries, or market data, the next step is to visit Solana Tracker and compare its API and SDK flow against the patterns in this guide.