kryptor.co.uk

A postal code API returns structured location data for a given ZIP Code or Canadian postal code. A typical response includes the code itself, city, state or province, county, latitude/longitude, and — where available — ZIP+4 detail. More complete services add time zone, area codes, boundary geometry, and demographic fields. You send a code (or an address), and the API sends back a machine-readable record you can store, validate, or display.

This article explains what those responses contain, how requests are usually shaped, and where postal code data fits into real applications.

First, clear up the word "code"

The keyword "code" is overloaded, and that causes real confusion for developers:

• Postal code — the ZIP Code (U.S.) or postal code (Canada) that identifies a delivery area.
• API key — the credential you use to authenticate your requests. It is not postal data.
• Source code — the program you write to call the API.

When someone searches for "postal code API code," they usually want example request/response code for a postal code service. The rest of this article treats it that way.

What a postal code API actually returns

Response fields vary by provider and endpoint, but the core set is fairly consistent. A single-code lookup commonly returns:

Richer datasets add 90+ fields: boundaries, population, income, elevation, and more. You rarely need all of them — request only what your application uses.

A representative JSON response

{
  "postal_code": "90210",
  "city": "Beverly Hills",
  "state": "CA",
  "county": "Los Angeles",
  "latitude": 34.0901,
  "longitude": -118.4065,
  "timezone": "America/Los_Angeles",
  "area_codes": ["310", "424"]
}

XML responses carry the same information in tag form. Choose based on what your stack parses most easily; JSON is the common default.

Common request patterns

Most postal code APIs support four patterns. Knowing which one you need prevents wasted calls.

1. Lookup by code

You have a code and want its details. This is the simplest and fastest call.

GET /lookup?code=90210

2. Reverse lookup by address

You have a street address and want to confirm or complete the code. This is the pattern behind checkout address validation.

GET /validate?street=...&city=...&state=...

3. Radius search

You have a center point and want all codes within a distance. Useful for store locators and delivery zones.

GET /radius?code=90210&miles=10

4. Batch validation

You have a file of addresses and want them cleaned in bulk. Batch endpoints trade latency for throughput and usually have their own limits.

Handling missing and ambiguous matches

Real data is messy. Plan for these cases:

• No match — the code doesn't exist or the address is malformed. Return a clear error rather than a silent empty object.
• Multiple matches — a city name may map to several codes, or a code may span several acceptable city names. Decide whether to pick the primary or return a list.
• Partial match — the street is valid but the ZIP+4 isn't. Fall back to the 5-digit code.
• Stale data — codes are added, retired, and reassigned. Refresh your dataset on a regular schedule.

A practical rule: validate at the point of entry, store the normalized result, and never re-derive it later from raw user input.

Practical use cases

• Checkout address validation — catch typos before shipping, reduce failed deliveries.
• Shipping zone lookup — map a code to a zone, carrier route, or rate table.
• Data enrichment — append county, coordinates, or demographics to existing records.
• Store and service locators — radius search to find nearby branches or coverage areas.
• Territory and tax logic — county and boundary data drive jurisdiction rules.

Licensing and data-source considerations

Postal code data originates with national authorities — USPS in the United States and Canada Post in Canada. Providers license and repackage it, which is why accuracy, update frequency, and field coverage differ between services. Before committing:

• Confirm the data source and how often it refreshes.
• Check whether ZIP+4 and boundary data are included or sold separately.
• Review usage limits and whether batch processing is allowed.
• Read the license terms for redistribution and storage.

Pricing and plan details change, so check the provider's current documentation rather than relying on secondhand figures.

Getting started

1. Decide which request pattern you need (lookup, reverse, radius, or batch).
2. Pick the fields you'll actually store.
3. Write a small test call and inspect the raw response.
4. Add error handling for no-match and ambiguous cases.
5. Cache results where the same codes repeat.

A postal code API is ultimately a translation layer: you give it a code or an address, and it gives back structured location facts. Understand the fields, match them to your use case, and handle the messy edges — that's most of the work.

Kryptor ships pre-built binaries for Windows (x64), Linux (x64 and ARM64), and macOS (x64 and ARM64), and is also available through several package managers. On macOS you must keep libsodium.dylib in the same folder as the kryptor executable, because a known .NET SDK issue prevents the library from being bundled into the binary. The steps below cover both install routes and how to verify what you downloaded.

Before you start

• Confirm your OS and architecture. The published builds cover Windows x64, Linux x64/ARM64, and macOS x64/ARM64.
• Decide between a pre-built binary and a package manager. Package managers handle placement and updates for you; manual downloads give you the signature and SHA-256 files for verification.
• Kryptor is licensed under GPLv3, so you can inspect or rebuild it from the GitHub source if you prefer.

Option 1: Download a pre-built binary

1. Go to the Kryptor download page and pick the build matching your platform: Windows (x64), Linux (x64), Linux (ARM64), macOS (x64), or macOS (ARM64).
2. Download the ZIP together with its Kryptor signature and SHA-256 digest files.
3. Verify the signature and digest before running anything. The project's Installation page documents the exact commands.
4. Extract the archive and run the kryptor executable from that folder.

Expected result: a working kryptor binary whose signature and hash match the published values.

macOS caveat: the upstream .NET SDK issue means libsodium.dylib is not bundled into the executable. Keep the libsodium.dylib file from the download ZIP in the same directory as the kryptor file, or the tool will not start. The project notes the .NET team has not investigated this for over a year, so treat it as a standing requirement rather than a temporary glitch.

Option 2: Install with a package manager

Expected result: the kryptor command resolves on your PATH. Run it once to confirm it launches.

Verify the install

• Run kryptor with no arguments (or its help flag) and check that usage information appears rather than a missing-library error.
• On macOS, if you see a libsodium-related load failure, re-check that libsodium.dylib sits beside the executable.
• If you installed manually, compare the SHA-256 digest of your download against the published value and check the Kryptor signature as described on the Installation page.

Common snags

• macOS "library not loaded" errors: almost always the missing libsodium.dylib placement described above.
• Wrong architecture: an ARM64 machine given an x64 build (or vice versa) will fail to run; re-download the matching build.
• Homebrew on macOS: there is no formula yet, so use the pre-built binary route instead of waiting on one.
• Updates: the project recommends following it on GitHub to stay current, since manual installs do not update themselves.

After installing

Kryptor is a file encryption and signing tool aimed at protecting files for backups and sharing while limiting metadata. It is positioned as a leaner alternative to GPG rather than a full replacement, so expect a narrower feature set focused on encrypting and signing files. Bugs, feedback, and support requests go through GitHub; security vulnerabilities should follow the project's SECURITY.md.

Kryptor's source code is hosted on GitHub, the project is licensed under GPLv3, and GitHub is also the place to report bugs, give feedback, ask questions, or request technical support. Security vulnerabilities should be reported according to the project's SECURITY.md file, and other enquiries can go to the author by email.

Source code and license

The site describes Kryptor as a file encryption and signing tool for Windows, Linux, and macOS, positioned as a leaner, more user-friendly alternative to GPG and a better version of age and Minisign. Its stated use case is protecting files for backups and sharing, with a focus on limiting metadata. It is explicitly not intended as a complete GPG replacement.

Support and contact channels

Use the channel that matches what you need:

• Bug reports, feedback, questions, technical support — GitHub. This is the project's stated primary channel for all of these.
• Security vulnerabilities — follow SECURITY.md rather than opening a public issue.
• Other enquiries — email the author at samuel at samuellucas dot com (the site writes the address this way to avoid scraping; convert it to a normal address before sending).

The site also asks users to follow the project on GitHub to stay up to date, which is the practical way to hear about releases and fixes.

Practical notes before you rely on the project

A few details from the site affect how you use the source and builds:

• macOS packaging caveat. For macOS (x64 and ARM64), an upstream .NET SDK issue prevents the libsodium library from being bundled into the Kryptor executable. Until it is resolved, you must keep libsodium.dylib (inside the download ZIP) in the same directory as the kryptor file. The site notes the .NET team has not investigated this for over a year, so treat it as a long-term constraint rather than a temporary glitch.
• Install routes. Pre-built binaries exist for Windows (x64), Linux (x64 and ARM64), and macOS (x64 and ARM64), each with a Kryptor signature and SHA-256 digest. Package managers include Chocolatey and Scoop on Windows, AUR on Arch Linux (kryptor from source or kryptor-bin for the published binary), and nix-shell -p kryptor on NixOS. Homebrew on macOS is listed as "help wanted," so don't assume a Homebrew formula exists.
• Verification. The site directs you to its Installation page for instructions on verifying signatures and digests. If you are building from source or using a package manager, checking the signature and SHA-256 against the published values is the step that ties a download back to the project.
• Project scale. The author describes himself as a student and asks for donations (PayPal, Monero). That context is relevant to expectations about support responsiveness and long-term maintenance.

What this means for choosing Kryptor

If your priority is an auditable, simply scoped encryption and signing tool and you are comfortable with GPLv3 terms and GitHub-based support, the source, license, and contact paths above are all you need to get started. If you need a vendor with formal support contracts, or you require a drop-in GPG replacement, Kryptor's own documentation says it is not aiming for that role.

Kryptor is a file encryption and signing tool for Windows, Linux, and macOS that positions itself as a leaner, more user-friendly alternative to GPG, built to combine what its author sees as the strengths of age and Minisign. It is not a drop-in GPG replacement: the stated use case is protecting files for backups and sharing with a focus on limiting metadata, and the project deliberately avoids GPG's breadth in order to keep the codebase small enough for a single person to audit. If you need GPG's ecosystem, smartcard support, or broad protocol compatibility, Kryptor is not the tool for that job.

The comparison at a glance

The GPG, age, and Minisign columns describe each project's general role; the Kryptor column reflects the project's own documentation.

Where Kryptor sits between age, Minisign, and GPG

Kryptor's author describes the goal as being "better than a combination of age and Minisign in terms of security and usability." That framing tells you what to expect:

• Against age and Minisign: Kryptor covers both encryption and signing in one tool, rather than requiring one utility for each. The project's emphasis is on a lean, user-friendly interface and on limiting metadata.
• Against GPG: Kryptor explicitly does not attempt to be a complete replacement. The documentation notes that chasing GPG parity would reintroduce the same problems: considerable complexity and too much code for one person to audit.

So the practical split is: choose GPG when you need its full feature set and interoperability; choose age or Minisign when you want a single-purpose tool; consider Kryptor when you want encryption and signing together in a small, auditable package with a simpler interface.

What to check before adopting it

Platform and packaging. Pre-built binaries exist for Windows (x64), Linux (x64 and ARM64), and macOS (x64 and ARM64). Package manager options include Chocolatey and Scoop on Windows, AUR on Arch Linux (source or binary), and nix-shell -p kryptor on NixOS. Homebrew on macOS is listed as "help wanted," so do not assume a Homebrew formula is available.

A known macOS caveat. The documentation states that an upstream .NET SDK issue prevents the libsodium library from being bundled correctly into the Kryptor executable on macOS (x64/ARM64), and that this has gone uninvestigated for over a year. Until it is resolved, you must keep libsodium.dylib (from the download ZIP) in the same directory as the kryptor file. If you deploy on macOS, plan for this extra file.

Verification. Each binary is published with a Kryptor signature and a SHA-256 digest, and the Installation page covers how to verify them. Verify before first use, especially if you download binaries outside a package manager.

Licensing and support. Kryptor is licensed under GPLv3, which matters if you plan to redistribute or embed it. Bugs, feedback, and questions go through GitHub; vulnerabilities go through the SECURITY.md process.

A quick decision guide

• You need broad compatibility, key servers, or a mature ecosystem: stay with GPG.
• You only need to encrypt files, or only need to sign files: age or Minisign respectively keeps things minimal.
• You want encryption and signing in one small, auditable tool with a simpler interface, and you accept a narrower scope: Kryptor fits that description, with the macOS libsodium caveat noted above.
• You are on macOS and want zero extra setup: check the current state of the libsodium issue before committing, since the workaround requires keeping an additional file alongside the executable.

Kryptor's download page publishes a Kryptor signature and a SHA-256 digest next to every pre-built binary (Windows x64, Linux x64/ARM64, macOS x64/ARM64). To verify a download, compare the file's SHA-256 hash against the published digest, then check the .sig file against the binary using Kryptor itself. The official step-by-step instructions live on the project's Installation page, which the download page links to; the outline below follows that documented flow. Verification confirms two things: the file arrived intact, and it was signed by the project's key.

What you need before starting

• The binary you downloaded (for example, the Windows x64 ZIP) and its matching .sig signature file from the same download row.
• The published SHA-256 value shown on the download page for that exact file.
• A way to compute SHA-256 locally: certutil -hashfile <file> SHA256 on Windows, shasum -a 256 <file> on macOS, or sha256sum <file> on Linux.
• Kryptor itself, to run the signature check. On first use you are trusting the copy you just downloaded, so the digest check matters — do it first.

Step 1: Check the SHA-256 digest

1. Compute the hash of the downloaded file with the command for your OS above.
2. Compare the output character-for-character with the SHA-256 value published next to that file on the download page.
3. If they differ, stop: delete the file and download it again. A mismatch means the download is corrupted or was altered in transit.

This step is a pure integrity check — it does not prove who produced the file, only that it matches the published bytes.

Step 2: Verify the Kryptor signature

1. Keep the binary and its .sig file in the same folder.
2. Run Kryptor's signature verification against the binary and the .sig file, following the exact command syntax on the Installation page.
3. A valid result means the signature was created by the project's signing key and the file has not changed since signing.

If verification fails, do not run the binary. Re-download both the file and its signature, and if it still fails, report it through the project's GitHub page (the documented channel for bugs and support).

Platform notes that affect verification

• macOS (x64 and ARM64): the download page states there is an upstream .NET SDK issue that prevents libsodium from being bundled into the Kryptor executable, and it is unlikely to be fixed. Until then, you must keep libsodium.dylib (inside the download ZIP) in the same directory as the kryptor file. Verify the binary as downloaded; don't separate the files afterward.
• Package managers: if you install via Chocolatey (choco install kryptor), Scoop (scoop bucket add extras; scoop install kryptor), AUR (kryptor or kryptor-bin), or NixOS (nix-shell -p kryptor), you are relying on the package channel rather than the download-page digests. The page lists Homebrew for macOS as "help wanted," so no Homebrew package is currently offered.
• Source builds: the source is on GitHub under GPLv3; signature and digest checks apply to the pre-built binaries, not to a local build.

When verification is worth the extra minute

Do it whenever you will use the binary for backups or file sharing — the stated use case — or move it to another machine. For a quick trial run on a throwaway system, the digest check alone already catches corrupted downloads; the signature check is what ties the file to the project.