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Postio.co.uk VS https://open-gpt.app/

Compare Postio.co.uk VS https://open-gpt.app/ and see what are their differences

Postio.co.uk

UK address, email, and phone validation APIs. Sub-50ms p95. Pay-per-request, no tiers, no contracts.

Rating
0 reviews
Pricing
Paid Free trial £0.02 (Address 2.2p (searching is free), Email & Phone 1p)
Alternatives Is it good?
https://open-gpt.app/

Create ChatGPT Application in seconds

Rating
0 reviews
Alternatives Is it good?
MailReach.co
The #1 email warming service to improve your deliverability by generating realistic and meaningful engagement to your emails. Easy-to-use solution to help you land in the main inbox instead of the spam folder. sponsored
Note: These products don't have any matching categories. If you think this is a mistake, please edit the details of one of the products and suggest appropriate categories.

Base details

Website, pricing, platforms and company facts side by side.

Postio.co.uk
https://open-gpt.app/
Website postio.co.uk open-gpt.app
Pricing
Paid Free trial £0.02 (Address 2.2p (searching is free), Email & Phone 1p) Official pricing
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Platforms
REST API Web JavaScript Node JS Python Go PHP Ruby .Net Wordpress Zapier +8
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Company Startup from the United Kingdom · 1 - 9 employees —
Listed in
Address Finder Address Verification API Postcode API Email Verification API Phone Number Validation +2
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About Postio.co.uk and https://open-gpt.app/

In their own words, as submitted to SaaSHub.

Postio.co.uk
https://open-gpt.app/

Postio is a UK validation API for developers. Address search and postcode lookup run on Royal Mail PAF data under a direct licence; email validation covers syntax, typo, MX and deliverability; phone validation does a live HLR carrier lookup. All endpoints are GET and return the same JSON...

Read more about Postio.co.uk

No description of https://open-gpt.app/ yet.

Features and specs

What each product offers, as listed by its team.

Postio.co.uk 9 features
https://open-gpt.app/ 5 features
  • Address search
    UK address typeahead over Royal Mail PAF data, held under a direct licence
  • Postcode lookup
    Every PAF delivery point at a given postcode
  • UDPRN lookup
    Full address record by Royal Mail Unique Delivery Point Reference Number
  • Email validation
    Syntax, typo correction, MX, SMTP check and deliverability classification
  • Phone validation
    Parse and validate, plus live HLR lookup for carrier, ported status and reachability
  • Pricing model
    Pay per request — 2.2p per address, 1p per email, 1p per phone. No tiers, no contracts
  • Free tier
    100 lookups, no card required
  • API design
    All endpoints are GET and return the same JSON envelope. Public OpenAPI spec, CORS enabled
  • SDKs and integrations
    Official SDKs for JavaScript/Node, Python, Go, PHP, Ruby and .NET. Drop-in browser widget (~4 KB gzipped), MCP server for AI agentsOfficial SDKs for JavaScript/Node, Python, Go, PHP, Ruby and .NET. Drop-in browser widget (~4 KB gzipped), MCP server for AI agents
  • Accessible AI Chat Interface
    Provides a user-friendly web-based interface for interacting with GPT-based AI models without needing to set up API access or coding knowledge.
  • No Installation Required
    Being a web application, it can be used directly from a browser without downloading or installing any software.
  • Potentially Free or Low-Cost Access
    Many GPT wrapper sites like this offer free tiers or lower-cost access compared to official API pricing, making AI chat more accessible to casual users.
  • Quick Setup
    Users can typically start chatting almost immediately after visiting the site, with minimal account creation or configuration steps.
  • Cross-Platform Compatibility
    Since it runs in a browser, it can be accessed from various devices including desktops, tablets, and smartphones without platform-specific versions.

Possible disadvantages

  • Uncertain Reliability
    Third-party GPT wrapper websites often depend on underlying API access that can be unstable, rate-limited, or discontinued without notice, affecting consistent availability.
  • Data Privacy Concerns
    Using an unofficial third-party service to process conversations raises questions about how user data and conversation history are stored, used, or shared.
  • Limited Transparency
    It may be unclear which underlying AI model version is being used, how up-to-date it is, or what modifications have been made to the base model's behavior.
  • Potential Hidden Costs or Ads
    Free-to-use AI wrapper sites often monetize through ads, premium upsells, or data collection, which may not be clearly disclosed to users upfront.
  • Lack of Official Support
    Unlike official AI platforms, unofficial wrapper sites may lack dedicated customer support, regular updates, or accountability if issues arise.

Analysis

An editorial look at what each product does well and who it suits.

Postio.co.uk
https://open-gpt.app/

No analysis of Postio.co.uk yet.

Overall verdict

  • I don't have verified, up-to-date information about open-gpt.app, and I'm unable to browse the internet to check its current status, reputation, or legitimacy. I cannot confidently vouch for or against this specific product/service.

Why this product is good

  • I lack real-time access to verify this website's current content, reputation, or user reviews
  • Domain names and their associated services can change ownership and purpose over time
  • Without verification, I cannot confirm if this is a legitimate service, its features, or its safety
  • There are many similarly-named AI tools of varying quality and trustworthiness, making specific verification important

Recommended for

  • Before using this site, research current user reviews on trusted platforms
  • Check the site's SSL certificate, privacy policy, and terms of service
  • Look for verified information about the company or developers behind it
  • Consider well-established alternatives like ChatGPT (OpenAI), Claude (Anthropic), or Gemini (Google) if you need reliable AI assistance
  • Exercise caution with any site requesting payment or personal information without clear verification of legitimacy

Category popularity

How often each product is chosen within a category, 0–100% relative to the other.

Score bands 0–20 21–40 41–50 51–60 61–100
Postio.co.uk
https://open-gpt.app/
100% 100%
Address Verification API
0% 0%
100% 100%
Phone Number Validation
0% 0%
100% 100%
Address Finder
0% 0%
100% 100%
Postcode API
0% 0%

Questions & Answers

As answered by people managing Postio.co.uk and https://open-gpt.app/.

What makes your product unique?

Postio.co.uk's answer

Postio charges only when a lookup returns a result — searching is free. Address, email and phone validation sit behind one API with a single JSON response envelope, so you integrate once rather than stitching three vendors together. Address data comes from Royal Mail's Postcode Address File under a direct licence, not scraped or resold sources. There are no tiers, contracts or minimum spend, and the first 100 lookups need no card.

Which are the primary technologies used for building your product?

Postio.co.uk's answer

A REST API served from edge locations, with official SDKs for JavaScript/Node, Python, Go, PHP, Ruby and .NET, all open source on GitHub. The API is documented by a public OpenAPI specification.

Why should a person choose your product over its competitors?

Postio.co.uk's answer

Pricing is published and pay-as-you-go: 2.2p per address, 1p per email, 1p per phone, billed only on a result. No sales call, no annual contract, no minimum commitment. You can be live in a few minutes with 100 free lookups and no card, and the same API covers all three validation types. For UK addresses specifically, the data is licensed directly from Royal Mail rather than obtained second-hand — which matters after the 2025 High Court ruling on database rights in this market.

How would you describe the primary audience of your product?

Postio.co.uk's answer

Developers and technical teams building UK-facing forms — ecommerce checkouts, signup flows, CRM and logistics systems. Typically small to mid-sized product teams, agencies building for UK clients, and software vendors embedding address lookup in their own product. It suits anyone who wants a UK-accurate API without an enterprise procurement process.

What's the story behind your product?

Postio.co.uk's answer

Postio is a trading name of Onno Group Limited, registered in England & Wales (company no. 08622799). It was built to make Royal Mail PAF-accurate UK validation available on straightforward pay-as-you-go pricing, rather than the contracts and minimum commitments that have been standard in this market. Address, email and phone validation were brought together behind one consistent API so a team can solve all three at once.

Who are some of the biggest customers of your product?

Postio.co.uk's answer

Serving a huge range of customers across the world looking for a blazing fast UK Address AIP product. From bootsrapped entrepreuners to FTSE 250 companies. We serve them all.

User comments

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Alternatives to Postio.co.uk and https://open-gpt.app/

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