
OpenRouter
liteLLM
Portkey
Eden AI
APIPark
Fireworks AI
Helicone AI
A unified, OpenAI-compatible gateway to every major LLM provider. One endpoint, one key, one bill - with automatic routing and failover.

DocRaptor
PDF Generator API
MailMergic
Doczilla
wkhtmltopdf
CraftMyPDF
Anvil PDF Filling API
Fill PDF forms, generate PDFs and Word documents, and collect e-signatures with one API.

Which is more popular?
Based on our record, DocSpring seems to be more popular. It has been mentioned 5 times since March 2021.
Website, pricing, platforms and company facts side by side.
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| Website | boldrouter.com | docspring.com |
| Pricing | ||
| Platforms | — | |
| Company | Startup from Switzerland · 1 - 9 employees · 2026 | Startup from the United States · 1 - 9 employees · 2017 |
| Listed in |
In their own words, as submitted to SaaSHub.


Point your existing OpenAI client at one endpoint and reach OpenAI, Anthropic, and more. Switch models by changing a single string - with automatic routing, failover, and one prepaid bill. Today the gateway routes 85 models across 23 providers behind a single endpoint. Full privacy - developed...
DocSpring is an API for filling, generating and signing documents. Developers build it into their products to turn data into finished PDFs and Word files. Start from the document you already have, or design one: PDF forms: upload any PDF, fillable or flat. AI finds the fields, names them, picks...
What each product offers, as listed by its team.


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


As answered by people managing boldrouter and DocSpring.
boldrouter's answer
boldrouter is designed for teams that want simplicity without being locked into a single AI provider. Developers can keep using familiar OpenAI-compatible SDKs while accessing models from OpenAI, Anthropic, Google, xAI, DeepSeek, Perplexity, Mistral, Z.ai, and others. Centralized routing, failover, usage tracking, billing, and API-key management reduce the infrastructure that teams otherwise need to build and maintain themselves. Its Swiss-hosted infrastructure is also particularly attractive to European and privacy-conscious organizations.
DocSpring's answer:
One API covers PDF forms, Word documents, page designs and HTML templates, with the same JSON and the same e-signatures, so you don't need a second tool when a customer sends you a Word contract. Templates have typed fields and validation that catch bad data before a document is made. Test PDFs are free and unlimited, and the free plan has no time limit.
boldrouter's answer
boldrouter is primarily built for software developers, AI startups, SaaS companies, engineering teams, platform teams, and enterprises building applications with large language models. It is especially useful for organizations that use, test, or compare multiple AI providers and want one centralized API, billing system, routing layer, and usage dashboard instead of managing separate integrations for every provider.
DocSpring's answer:
Developers and product teams who build documents into their software: loan, insurance and rental applications, patient intake and consent forms, tax and government forms, contracts, invoices and certificates. That includes SaaS companies whose own customers set up templates in DocSpring's embedded editor.
boldrouter's answer
boldrouter was created by Swiss technology group Cybrient Technologies SA to simplify the increasingly fragmented LLM ecosystem. As companies began using models from multiple AI providers, managing separate APIs, credentials, billing systems, monitoring, and failover logic became increasingly complex. boldrouter was built as a unified layer between applications and AI providers, allowing developers to integrate once and then choose or switch between models as their requirements evolve. The platform officially launched its public beta on July 21, 2026 in Zürich, Switzerland.
DocSpring's answer:
I used to work at a payroll company (Gusto). We had built a similar in-house tool for filling out tax forms. I then built the first version of DocSpring (formerly named FormAPI) while I was living in Thailand. I built it to automate the filling out of visa application and visa extension forms, but realized that it could also be used for tax forms, real estate contracts, and any other kind of fillable PDF form.
boldrouter's answer
No major external customers have been publicly disclosed yet. boldrouter launched its public beta on July 21, 2026, so publicly announced customer references are still limited.
DocSpring's answer:
boldrouter's answer
The platform incorporates multi-model routing, automatic failover, token metering, scoped API-key management, usage analytics, centralized billing, and Swiss-hosted cloud infrastructure. The underlying programming languages and internal framework stack have not been publicly disclosed.
DocSpring's answer:
Ruby on Rails, React, Rust, Go, AWS
boldrouter's answer
boldrouter is a Swiss-hosted unified LLM gateway that gives developers and businesses access to leading AI models through a single API key and an OpenAI-compatible interface. Its distinctive combination of multi-provider access, smart routing, automatic failover, centralized billing, token-accurate metering, scoped API keys, usage analytics, and enterprise controls allows teams to use multiple AI providers without rebuilding their applications for each one.
DocSpring's answer:
DocSpring fills every kind of document from one API: PDF forms, Word documents, page designs and HTML templates. AI sets up the fields on any PDF, fillable or flat. The same template gives you a web form and e-signatures, and your customers can set up their own templates in our editor, embedded in your app. Your AI assistant can do all of this too, through our MCP server. DocSpring is SOC 2 Type II audited and HIPAA compliant, with US or EU hosting.
Share your experience with using boldrouter and DocSpring. For example, how are they different and which one is better?
Recommendations tracked on public social media and blogs since March 2021.


Tracking boldrouter since Aug 2026.
I'm still working on DocSpring [1], originally launched on Hacker News in October 2017 under the name "FormAPI." It's a PDF generation API with a template editor UI for setting up fields on PDF forms. It makes it easy to turn complex tax... - Source: Hacker News / over 1 year ago
For programmatic filling of PDFs, have a look at DocSpring: https://docspring.com. - Source: Hacker News / over 2 years ago
Great post. I've spend a lot of time reading through the PDF specification over the last ~5 years while building DocSpring [1], and I still feel like I've barely scratched the surface. Qpdf is a great tool. One of my other favorites is... - Source: Hacker News / about 3 years ago
When comparing boldrouter and DocSpring, you can also consider the following products.


As the only API powered by the Prince HTML-to-PDF engine, DocRaptor provides the best support for complex PDFs with powerful support for headers, page breaks, page numbers, flexbox, watermarks, accessible PDFs, and much more
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PDF generation API that turns your JSON data into documents from templates built with AI or a drag-and-drop editor, which your users can edit inside your app through a white-label embedded editor.
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Build production-grade & reliable AI apps with Portkey
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Effortless Mail Merge for PDFs — Generate, personalize, and send documents in minutes, not hours.
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