Lob.com
Lob is the direct-mail and address-verification API for developers. Its REST API lets teams programmatically create and mail postcards, letters, checks, self-mailers, snap packs, booklets, buckslips and cards; verify and autocomplete US and international addresses; run direct-mail and USPS Informed Delivery campaigns; manage HTML templates; and track physical delivery through USPS scan events surfaced over webhooks. The API is organized around REST with resource-oriented URLs, HTTP Basic authentication using test_/live_ API keys, cursor pagination, Idempotency-Key support, and standard rate-limit headers. Lob was surfaced as an a16z portfolio company and enriched into the API Evangelist network from its public OpenAPI, docs, SDKs, and registries.
Real signal across most facets with visible, nameable gaps — the contract exists but is thin, or the portal is good while governance and commercial terms are absent.
API Evangelist profiles Lob.com the way a machine reads it — 35 machine-readable artifacts across 30 APIs, pulled from the provider's own public surface and indexed so a developer, an analyst, or an AI agent can evaluate it against every other provider on the network.
Every provider in the network is reduced to the same set of machine-readable artifacts — OpenAPI contracts, event specifications, GraphQL schemas, runnable collections, pricing and rate-limit signals, security posture, OAuth scopes, and the agent surfaces (MCP servers and skills) that let software drive the API on its own. We profile them because the interface is the part of a company you can actually inspect: it is a truer signal of what a provider does than any marketing page. From those artifacts we compute the Kin Score — Lob.com scores 58.8/100 (developing), with a separate agent-readiness read of 84/100 (agent native). The full breakdown is below, followed by every artifact we hold — each card links through to its machine-readable definition on apis.io.
Kin Score
This is the API Evangelist rating — a single, repeatable read computed from the artifacts on this page. Green fill is points earned; the red track is points possible, so every bar shows earned-versus-possible at a glance.
Kin Score
How this is scored →scored 2026-07-27 · rubric v0.5
How we profile Lob.com
Each block below is one kind of artifact we hold for Lob.com. For each we say what it is and why it earns a place in the profile, then list every one we've indexed — capped at two rows, scroll within the panel for the rest.
APIs 30
Each API is captured as its own OpenAPI definition — every operation, parameter, and response. This is the single most useful machine-readable description of what an API does, and it's what lets us score, lint, mock, and generate against it without asking the provider for anything.
Individual APIs this provider publishes, each with its own machine-readable definition.
Lob.com Accounts API
The Accounts API from Lob.com — 1 operation(s) for accounts.
Lob.com Addresses API
To add an address to your address book, you create a new address object. You can retrieve and delete individual addresses as well as get a list of addresses. Addresses are ident...
Lob.com Bank Accounts API
Bank Accounts allow you to store your bank account securely in our system. The API provides endpoints for creating bank accounts, deleting bank accounts, verifying bank accounts...
Lob.com Billing Groups API
The Billing Groups API allows you to create and view labels that can be attached to certain consumption-based usages of Letters, Checks, Postcards and Self-Mailers to customize ...
Lob.com Booklets API
The Booklets API from Lob.com — 2 operation(s) for booklets.
Lob.com Buckslip Orders API
The Buckslip Orders endpoint allows you to easily create buckslip orders for existing buckslips. The API provides endpoints for creating buckslip orders and listing buckslip ord...
Lob.com Buckslips API
The Buckslips endpoint allows you to easily create buckslips that can later be used as add-ons for Letters Campaigns. Note that a Letter Campaign with Buckslip add-on requires a...
Lob.com Campaigns API
The campaigns endpoint allows you to create and view campaigns that can be used to send multiple letters or postcards. The API provides endpoints for creating campaigns, updatin...
Lob.com Card Orders API
The card orders endpoint allows you to easily create card orders for existing cards. The API provides endpoints for creating card orders and listing card orders for a given card...
Lob.com Cards API
The cards endpoint allows you to easily create cards that can later be affixed to Letters. The API provides endpoints for creating cards, retrieving individual cards, creating c...
Lob.com Checks API
Checks allow you to send payments via physical checks. The API provides endpoints for creating checks, retrieving individual checks, canceling checks, and retrieving a list of c...
Lob.com Creatives API
The creatives endpoint allows you to create and view creatives. Creatives are used to create reusable letter and postcard templates. The API provides endpoints for creating crea...
Lob.com Identity Validation API
Validates whether a given name is associated with an address.
Lob.com Informed Delivery Campaign API
The Informed Delivery campaigns API allows you to create and view Informed Delivery campaigns.
Lob.com Intl Verifications API
Address verification for non-US addresses
Lob.com Letters API
The letters endpoint allows you to easily print and mail letters. The API provides endpoints for creating letters, retrieving individual letters, canceling letters, and retrievi...
Lob.com Lob Credits API
The Lob Credits API from Lob.com — 1 operation(s) for lob credits.
Lob.com Postcards API
The postcards endpoint allows you to easily print and mail postcards. The API provides endpoints for creating postcards, retrieving individual postcards, canceling postcards, an...
Lob.com QR Codes API
Lob QR codes allow you to generate a QR code that is unique to each mailpiece, thereby allowing each and every customers to receive a personalized link. See the Create endpoint ...
Lob.com Resource Proofs API
The resource proofs endpoint allows you to create a final rendering of any template. This is best practice to ensure that you are visually validating your creative before any ma...
Lob.com Reverse Geocode Lookups API
Find a list of zip codes associated with a valid US location via latitude and longitude.
Lob.com Self Mailers API
The self mailer endpoint allows you to easily print and mail self mailers. The API provides endpoints for creating self mailers, retrieving individual self mailers, canceling se...
Lob.com Snap Packs API
The Snap Packs API from Lob.com — 2 operation(s) for snap packs.
Lob.com Template Versions API
These API endpoints allow you to create, retrieve, update and delete versions of reusable HTML templates for use with the Print & Mail API.
Lob.com Templates API
These API endpoints allow you to create, retrieve, update and delete reusable HTML templates for use with the Print & Mail API.
Lob.com Uploads API
The uploads endpoint allows you to upload audience files that are then associated with a given campaign. At this time, only CSV files are allowed. The API provides endpoints for...
Lob.com URL Shortener API
Lob's URL shortener allows you to generate unique short links, either with Lob's own domain or your own custom domains. Each custom link enables Lob to track mail individually a...
Lob.com US Autocompletions API
Given partial address information, this endpoint returns up to 10 address suggestions.
Lob.com US Verifications API
Validate, automatically correct, and standardize the addresses in your address book based on USPS's Codi...
Lob.com Zip Lookups API
Find a list of cities, states and associated information about a US ZIP code.
Scroll within the panel for all 30 ·
MCP Servers 1
Model Context Protocol servers expose these APIs directly to AI agents. We profile them because agent-native access is the fastest-growing way this provider's capabilities actually get used.
Model Context Protocol servers that expose these APIs to AI agents.
lobcom-mcp.yml
MCP SERVEREvent Specifications 1
Not every API is request/response. AsyncAPI describes the event-driven and streaming side — the webhooks and channels — so the asynchronous half of the interface is documented the same way the synchronous half is.
AsyncAPI definitions for this provider's event-driven and streaming APIs.
Lobcom Webhooks
ASYNCAPISecurity Posture 2
Authentication, domain security, vulnerability disclosure, and trust-center signals — the evidence that a provider takes security seriously enough to document it. We profile it because you can't govern what you can't see.
Authentication, domain security, vulnerability disclosure, and trust-center signals.
Agentic Access 1
An x-agentic-access contract marks which operations are safe for an agent to run on its own and which need a human in the loop. It is the difference between an API an agent can use and one it can use safely.
Recommended x-agentic-access execution contracts for AI agents.
Resources
Every other property we hold for Lob.com — documentation, portals, status pages, policies, and corporate surface — grouped by the job it does, following the integrator's arc from getting started to running in production.
Get Started 5
Portal, sign-up, and the first successful call
Documentation 2
Reference material describing how the API behaves
Agent Surfaces 5
MCP servers, agent skills, and machine-readable catalogs
Design & Contract 8
Pagination, idempotency, versioning, errors, and events
Scroll within the panel for all 8 ·
Build 3
SDKs, sample code, and the tooling you integrate with
Access & Security 2
Authentication, authorization, and security posture
Operate 4
Status, limits, changes, and where to get help
Commercial 3
Pricing, plans, and the legal terms of use
Company 1
The organization behind the API
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